Robust Paths to Global Stability:   Tough but Feasible *

H. Benking (a), G.W. Brauer (b), T.M. Fliedner(c), C. Greiner (a), P. Malaska(d), K. Morath (e), R. Pestel (f),  F.J. Radermacher(a)*

1995

Abstract I  - The Global Challenge II - Scenarios, Perspectives Summary References Appendix (text for omitted diagrams) Authors' Organizations Presentation history and current Internet links

 

 ABSTRACT

     The vision of an enduring, environmentally-sustainable development process is challenging politics, economics, and society in general with a new understanding of global welfare. It poses the question as to whether, and how, it will be possible, on a global basis, to change direction towards an enhanced world-wide stability and long-term sustainable welfare for all. Above all, the vision requires that ecological constraints be reflected in the way natural resources are exploited, and that an end be put to the world's population explosion.
     This text provides an overview of the problem we face, and outlines a path to a possible solution. It concerns itself with the characteristics, and the fundamental achievability, of 'robust paths' leading to a long-term and environmentally-sustainable development process. Besides providing a direction and some ideas, the proposed path serves as a yard-stick, by reference to which the performance of actual policy options can be evaluated. At the same time, it demonstrates that, if we act quickly, it may be possible to buy time; time which could permit future generations a broad range of options for action, instead of being forced into a perpetual situation of crisis management. Precisely because the concept of sustainable development takes into consideration the long-term consequences of today's actions, this text argues, it is absolutely imperative to avoid taking a 'wait-and-see' attitude.

     The paper describes the conditions required for the proposed robust paths, and suggests some possible ways in which they might be structured. Some of the elements contained in these paths have, for some time and in various combinations, been the subjects of much public discussion, including such ideas as the reduction of material resources used in particular products or services (dematerialization) and global ecological taxation. On the other hand, they also incorporate elements which have, thus far at least, not played much of a role in the public debate about sustainability. Especially noteworthy here are ideas involving economic incentives and world-wide social security systems to stimulate a reduction in the world's population and to prevent the rebound effects usually associated with technological progress.
     Applied individually, all of the above mentioned elements will not in and of themselves stabilize the global situation; however, it may be possible to combine them in such a way that they are seen as necessary and sufficient, as well as mutually-strengthening and complementary, elements of the solutions which are referred to
herein as robust paths to sustainability. The ideas and conclusions proposed are, in part, supported with basic calculations and computer model simulations (not presented here in detail; see the Appendix for an overview of the model used). This approach has the advantage of yielding unambiguous, if provisional, parameter sets for the proposed paths or solutions.
 
 

 I. THE GLOBAL CHALLENGE

 The inability to sustain the present global situation can be characterized by three critical trends:

• overpopulation and continuing population growth, especially in the developing countries;
• over consumption and accelerating resource exploitation, primarily in the developed countries, but increasingly also in various countries in transition to a higher state of development;
• social disintegration, caused by an increase in the (by now, excessive) speed of innovation processes in all areas; processes which are being driven by technological and economical dynamics, but which are not being societally controlled, and which are leading to growing unemployment, social unrest and corresponding threats to social security systems.

 The above trends are to some extent caused by highly developed (and generally encouraged) national and international systems designed to promote innovation, by the world economic order, and (in part) by extreme national and international social differentiation. Unless alleviated, they will in turn bring about social destabilization, an excessively rapid exploitation of exhaustible or only partially renewable resources, as well as an overloading of the environment as a dump for toxic waste materials [35, 36].

 While the need for such steps as a turnaround in the world's population growth or a reduction in world-wide resource exploitation have been discussed for a long time, feasible strategies to achieve those ends, let alone the necessary practical political steps, have never been clearly identified. And time is now pressing. If concrete changes and change-inducing processes, which clearly demonstrate that sustainable development is possible world-wide, do not soon become evident, say within about 20 years, then it can be anticipated that policy alternatives of quite a different (and far less benign) sort will show up on the political agenda.

 If currently available analyses are correct, humankind is moving rapidly, in ecological, economic, as well as political terms, towards a watershed. First, ecological and economic situations will become increasingly more critical the longer we avoid making those changes in direction which will ultimately happen anyway. In addition, the longer these ecological emergencies and social dislocations are allowed to proliferate and worsen, the more unmanageable the situation will become politically. Therefore, it must be clear that the undesirable, yet ultimately inevitable, alternative to timely rational action now, is the management of global catastrophes and the concomitant conflicts later.

 While failure to master the global situation within the coming decades will, of course, be extremely costly for all nations, it will be especially disruptive in the developed countries, and might even lead to the collapse of civilized society as we know it. Given that the unequivocally-disastrous consequences of conducting 'business as usual' on this planet are by now pretty obvious, the goal of avoiding them should mobilize responsible individuals and accountable organizations of all social and political persuasions. Efforts to address the problems and undertake the necessary measures can no longer be postponed.

 Specifically to be undertaken, and this preferably on the basis of global consensus, is the large-scale abandonment of the developmental pattern set, up to now, by the industrialized nations. However, developing countries can be expected, understandably, to resist such a reorientation (that is to say, restriction) of their
 developmental options. Unless of course the industrialized countries were prepared, by way of innovative mechanisms, to institute a world-wide redistribution, at their expense, of opportunities for development. The only hope is that developing countries might be convinced to endorse a program of development which aims at
 ultimate equity and fairness with regard to living conditions, health and quality of life, and opportunities for advancement everywhere on earth.

 To this end a globally-negotiated solution, consisting of two key elements, should be sought:

 - The industrialized countries must support the developing countries in all steps which will help to end the population explosion. This can be achieved, above all, by the creation of global old age security systems, by the development of educational systems, by the transfer of knowledge from the developed to the developing world via appropriate information technology, and by the betterment of the social position of women, etc. By bringing about a minimum level of social standards world-wide and by enhancing the chances for a global implementation of human rights, this step will have a major impact on health and the quality of life, especially in developing countries.

 - The above measures must be accompanied by a verifiable and enforceable global system for the husbanding of scarce resources and the control of pollution; certainly, this system would include an economic instrumentarium for eliminating the destruction of forests and for limiting the emission of climate-threatening gases. Such an approach will, in particular, facilitate the setting of minimum levels of ecological standards world-wide.

 What must be made especially clear is that the issue is not one of charity, where the richer countries generously offer to help the poorer countries. Rather, it is more a question of enlightened self-interest: how can all countries, and especially those who are presently well situated, best and most quickly contribute to securing their own present and future chances of survival and standards of living.

 The next twenty years will be decisive. As the simulations described in the second part of this paper suggest, this window of opportunity has an additional significance: all delays during this important time period will significantly worsen the long-term achievable environmental quality. The inevitable, if delayed, expenditures to pay for the results of having neglected a path of sustainable development, will accordingly be many times higher than preventive outlays would be, if the latter are made within the next twenty years. The later the turnaround in thinking is achieved and, thus, the longer the journey in the wrong direction, the more difficult and costly (and the more unlikely) it will be to achieve global stabilization via sustainable development.

 Expectations of robust developmental pathways

 A robust path, of the kind described here, should have as its key goal the achievement of a comparable quality of life, especially with regard to health and old age security, for the people of all countries. This is necessary because, especially in poorer countries, excessively large gradients in health and prosperity have been shown to foster a willingness to accept ecological degradation and other disadvantages in exchange for even a small (often temporary) increase in economic and personal well-being. Exploitation of workers, child labour, the export of garbage, etc. are the predictable consequences of such inequity. Such conditions, in the long run, disrupt social stability and peace, and erode any chances for global stability. Besides, it is only too understandable, and even legitimate, for those countries who are (relatively) less privileged to take all possible opportunities and make all necessary efforts in order to change the present asymmetries more in their favour, thus further accelerating the destructive competition for resource consumption.

 Real and enduring global solutions must be based on consensus. In such a short period of time as twenty years, change will be possible only by joint efforts and with the consensus of a wide variety of people and institutions [26]. This is true, in particular, for the large religious communities and political parties who will, with respect to many issues, not deviate much in the short term from their traditional positions. The needed adaptations in generally-held belief systems are unlikely to happen, if they happen at all, unless embedded in a universally-fair concept of development. Certainly, it will make little sense to propose solutions that are diametrically opposed to prevailing values and trends.

 Similarly, although this paper focuses on the ecologic, economic, and demographic aspects of sustainable development, it must be emphasized that the health and quality of life of human individuals, families and communities, must be at the heart of all notions of sustainable development on this planet. It is herewith noted that
 the very purpose of sustainable development, and the ultimate goal of the robust paths being proposed, is the full realization of the health and well-being potential of the human being. That a healthy environment and thriving natural ecosystems all over the globe are a sine qua non for this, is obvious.

 If the main approach to a global solution consists only of appeals for the abolition of cars or the reduction of leisure-time activities, for family planning strategies that go against prevailing mores, or for social equality and better education of women in developing countries, then these - in isolation - are probably doomed to failure -
 either because they take too much time, or because they are likely to encounter heavy social or religious resistance. This is true, although any of the measures mentioned are, or may be, indispensable as part of a multi-factorial solution - especially as the examples of India and China have taught us that compulsory measures
(e.g. in family planning) have only limited effectiveness.

 This applies also to 'solutions' which demand that (only) developing countries reduce their population numbers, or exercise restraint in energy utilization. Such demands will be ignored unless they are accompanied by forms of substantial compensating contributions from the developed regions. Such a balance might be struck if those in developing countries feel that they have a realistic expectation of an immediate and steady improvement in their economic situation and, at the same time, equal or more severe demands are being made of the people in developed nations. Similarly, any demands that would, in both poor and rich countries, result in a noticeable lowering of the quality of life which people have already achieved, are also not promising.

 Solutions assume institutions

 With enlightened self-interest on the part of the developed countries, it is conceivable that the formation of international agreements along the lines of the globally-negotiated solutions proposed herein could be achieved, even if they involve substantial contributions by the developed countries to the developing ones. Enforcement and monitoring of such agreements presuppose the existence of suitable regulations and appropriate institutions (in this regard see also the discussion of related questions in [8]).

 Once reached, a globally-negotiated solution still faces many obstacles. While respect for national self-determination motivates the search for solutions whose components are maximally decentralized, some form of supranational institutions for monitoring and enforcement will probably be necessary. To be acceptable, they
 must be lean and have transparent policy-making and regulatory structures which work reliably in crisis situations, when their ability to function will be essential. The difficulties which such institutions will have to deal with become clear when one considers issues such as the separatist movement in northern Italy, the co-ordination difficulties of the EU, the problems encountered by the UN in Somalia, Bosnia and elsewhere, etc. And there will be other obstacles: Subordinate units often consider their interests to be inadequately appreciated by the central institution, while national self-esteem will repeatedly (and predictably) call into question the agreed-upon consensus.
 Accordingly, the success of a globally-negotiated solution will depend on the success of these supranational institutions; that is, they must be given adequate authority. These institutions should first of all see to it that adequate frameworks for policy formulation and analysis are put in place, and be less concerned with the
 generation of actual solutions. The trick will lie in the institutions' ability to maximize initiative, at both the inter- and intra-state level of action, while preserving freedom, self-determination, and equity.

 Robust solutions assume the implementation of workable sanctions and the existence of effective stimulation mechanisms. In spite of their recognizing the necessity of global measures against problems such as the population explosion, the excessive exploitation of natural resources, or the impending climatic catastrophe, not all states will be willing (at least in the beginning) to participate actively in their solutions. On the contrary, there may even be big incentives to remain distanced from the acceptance of a common solution. Such behaviour might especially be expected from some countries which, upon joining in a globally-negotiated solution, would become donors (especially if their non-participation does not jeopardize the implementation of a solution). What we are talking about here is the typical 'free-ride' problem: If a majority of states undertake measures, for instance, to curb the overpopulation problem or reduce atmospheric pollution, then those states which do not contribute will also benefit, i.e. "get a free ride". The need to avoid this situation has consequences for the necessary characteristics of sought-for solutions:

      Unilateral optimization options cannot be allowed. Whoever wants to take part in a globally-negotiated solution must do this under conditions which apply to all. All characteristics of a globally-negotiated solution should if possible be determined at the time of the agreement, and should be valid for the total duration (i.e. years or even decades) both of overall, as well as of corresponding specific, agreements.

      There must be no incentives for a 'free ride'. Those who wish not to associate with the solution should not be allowed to benefit at the expense of those participating in the solution. In so far as such third parties profit from the solution (e.g. by being beneficiaries of the result of environmental improvements), there must be mechanisms to transfer the unearned benefit back to the problem solvers. The foundation for this could be provided by elements of an environmentally-oriented world-trade agreement; for instance, by levying special duties or resource taxes on all international trade transactions in which those countries who are not taking part in the desired globally- negotiated solution wish to participate. This means that an initial coalition for the solutions proposed here need, in the beginning, not include all states, but should be strong enough to modify GATT/WTO regulations.

      It will require a globally-constituted regulatory or policy-making structure, the decisions of which are binding under international law, to guarantee these characteristics, also in so far as it may be necessary to impose sanctions on non-compliant signatories of the globally-negotiated solution.

 To summarize: Solutions which are expected to provide substantial opportunities for securing the future must be acceptable under currently existing systems and conditions, and as much possible should not disadvantage anyone. Furthermore, they should demonstrate a way in which everyone will, in the foreseeable future, be visibly better off. At the same time, in order to reach broad acceptance, robust global solutions should reduce, continuously and consistently, the pollution of nature all over the world. The basic thoughts underlying such solutions must be intellectually comprehensible in and of themselves, they must be amenable to a broad
understanding and acceptance, and it must be demonstrably clear to everyone that, over the years, this path will lead to a substantial, permanent and world-wide improvement in the conditions of humankind and nature. The core of such a path should be able to be accepted, regardless of political or religious orientation, as a correct way into the future. In this way, such paths will acquire the characteristic of a 'solution-attractor' and lead directly to further solutions.

 The core elements of a solution

 Robust paths to an enduring, environmentally-just development should lead to globally-comparable prospects for living conditions and prosperity and should permit the achievement of a substantial lowering of environmental pollution. They should not require anyone to accept a lowering of their present quality of life, but should rather make possible a steady and visible improvement in the living conditions of all people. They must furthermore be able to coexist with today's most important world views, and must therefore avoid direct conflict with the mainstream of present-day political, ethical or religious convictions.

 From a system theory point of view, proposals of such solutions, within simulation models, are likely to incorporate at least the following three elements [26]:

 1. a substantial reduction in the human population in all countries achieved by appropriate, especially economic
 and social systems of incentives, and the substantial support of the less developed countries by the richer states
 (made politically more acceptable by population reduction).

 2. a dramatic reduction in the relative use of material and energy, i.e. the amount of material and energy
 consumed for a unit of service, product or functionality due to technological and organizational progress
 (dematerialization).

 3. a noticeable decrease, on a global scale, in the total amount of material and energy consumed by goods,
 services, and functionality, i.e. a noticeable decrease on a global scale in all forms of exploitation of the
 environment. This has to be accelerated and facilitated by suitable conditions and policies (e.g. global
 "taxation-at-source" of non-renewable resources), e.g. within the political framework of a global,
 socio-ecological market economy. Such frameworks should, in particular, function in such a way as to slow
 technological innovation and avoid rebound effects.

 Systemic incentives for population reduction

 It is likely that, over the next fifty years, humankind will nearly double in size to about 10 billion [4, 5, 7, 15, 25, 26, 31]. Economic incentives must be used to slow this growth as much and as soon as possible. Admittedly, economic factors are by no means the only (or even the most important) determinants of the number of children in a family; yet, it is likely that substantial economic incentives would be effective, especially in extremely poor populations, who might, for the first time ever, see the possibility of a better future for themselves and their children.

 It will, of course, be necessary to think carefully about how economic incentives might work with respect to achieving smaller families. For instance, the development of Germany between 1880 and 1980, during which time the population more than doubled, has shown that increasing prosperity, including the introduction of old age pensions, does not necessarily lead to a reduction in the number of offspring. It would therefore appear to be especially important, initially, to provide economic incentives (perhaps in the form of pensions, educational opportunities, and/or health care) exclusively to families with few children. It is to be hoped that those families in developing countries who opt for such lifestyles will quickly become role models for social improvement and, in no more than 30 to 40 years, will pull the rest of the population with them (see also Part II of this paper).

 For reasons of balance and acceptability (in terms of fairness), the population numbers in the developed countries must shrink in a manner comparable to the reduction in the developing countries. One possible goal might be to reduce, in about 300 years, the world's population from a peak of 10 billion in 2050 (which is probably unavoidable) to a total global population of one tenth of that size, that is to 1 billion people. A population reduction of this order of magnitude would allow the realization of a higher quality of life for everybody than we can achieve today, even in the G7 countries. That improvement would, furthermore, be achieved with sustainable economics (based for the most part only on the use of renewable raw materials), and it would furthermore ensure a high likelihood of persistence (robustness) of this condition. For the developed world (essentially the G7 countries), which today encompasses about 1.2 billion people, the foregoing proposal implies a targeted (long-term) reduction of the population to about 250 million people. In the developing countries, which will nearly exclusively be responsible for bringing the world's population to 10 billion, this would mean a reduction to about 850 million people by the year 2300. At the end of this adaptation process, the size relationship between the populations of the developed countries and those of the developing countries of the world would be roughly what it is today, albeit reduced at that time by a factor of 5.

 A reduction in the world's population by a factor of 10 (from a peak of 10 billion in 2050) in about eight generations, calls for the achievement of an average fertility rate of 1.5 children per adult female; in Germany this figure is at present already lower, and in Italy it is only 1.2. The experience in Germany is that such shrinkage
 causes political problems as well, but for a multi-generation transition phase of a global stabilization process this is probably acceptable. Given the alternatives, it is probably the most humane way in which to accommodate necessity in an already unbalanced global situation.

 The world-wide lowering of the rate of human reproduction, surely the most challenging of the aims discussed here, is to be achieved through extensive educational efforts and massive investment in social systems. At first these investments are best focused largely on families with few children, and in such a way as to represent an alternative to the traditional function of children as security against old age and other risks. All of the proposed measures rely on voluntary decisions on the part of individuals, without putting undue pressure on families which may still prefer to have more children. This point is of crucial importance with respect to any attempt at reaching a broad societal consensus. For example, the proposed approach is designed to be compatible with the Catholic Church's concept of ”responsible parenthood”. Also, additional financial aid should flow immediately into programs which would benefit all families, regardless of size. These would include education and vocational training, special training opportunities for women and other improvements in their social status, health care. The most important starting point, however, is still the establishment of pension schemes which are initially to be offered only to families which elect to have a small number of offspring.

 A global consensus with regard to a reduction in population will only be achieved if, at the same time, the richer nations are willing to accept a commensurate shrinking of their own numbers. This will further enhance the environmental benefit, as resource consumption and the resulting environmental pollution are by far the most extensive in the richer countries. Ongoing technological progress and the increasing automation of production processes will, in spite of a reduction in numbers, permit a high level of production in the industrialized countries.
If necessary, it may even allow a modest amount of economic growth, from which, given their shrinking population, a politically-mandated flexibility could ensure that a reasonable share of these benefits would flow to the developing nations as well. In this sense, the funds liberated in this manner could be used by the respective
 developed country as its contribution to the transformation process, without having to reduce the per capita income of its own citizens.

 A particularly promising method by which these contributions could be raised involve coupling this with a method to limit global resource exploitation. Because, in order to achieve the latter by way of economic measures, it will be necessary first to price resources in a manner which better reflects their scarcity and/or non-renewability. On the other side of higher costs of resource exploitation are the corresponding revenues raised on the use of
particular resources by global 'taxation at source'. These taxes would at first be paid primarily by the developed countries, as these will likely, and for the immediate future, have a relatively high rate of resource exploitation. Incidentally, the need, and resulting pressure, to raise these funds has some positive effects as well. Besides the dampening effect on resource exploitation and the lowered production of toxic effluents, there will also be a permanent deceleration, or at least more societal control, of technological innovation. In a world, which will by then be less influenced by social gradients and inequities, this is highly desirable, given the run-away acceleration which has characterized these processes to-date. The raising of these funds in the framework of a globally-negotiated solution is thus, for the developed countries, a cost-effective and reasonable method with which to counter the threat of a potential catastrophe. Actually, this might be the only realistic long-term stable route to maintain, or even enhance, their own high standards of living.

 Global at-source taxation and alternative financing options

 The notion of first making it more expensive, globally, to exploit scarce or non-renewable resources, to pollute the air, soil or water, or to create hazardous materials, and then to use the resulting funds to finance the above described measures, represents a deliberate linking of the world's population problem to the world's resource and development problem [2, 3, 18, 19, 28, 29, 32, 33, 34]. If successful, a reduction in population growth would directly facilitate efforts at limiting resource exploitation. Conversely, if the use of economic levers manages to reduce the exploitation of specific resources, this will reduce, somewhat, the pressure for demographic change.

 Due to the higher degree of economic activity in the developed countries, the higher cost of resources will be felt primarily by these countries. These higher prices are to be established so that absolute limits on the use of certain resources, as well as on the creation of hazardous materials, can be enforced world-wide. In the long run, resource exploitation should progressively decrease until it reaches levels consistent with long-term sustainability.
This kind of pricing will have the effect of increasing performance efficiency, and bringing about equal or better service quality with lower resource expenditures. This point will be discussed in more detail below.
An international scheme of at-source taxation would yield resource prices which reflect both the scarcity of  resources as well as the pollution created by their utilization, and is one way in which to reduce resource exploitation. But the number of financing options is by no means limited to such measures. All arrangements which  meet one of two basic requirements will suffice:

   1.Transfer of resources (of appreciable size) into countries which have no comprehensive social security
      systems and correspondingly high reproduction rates; in which case the transfer should flow into the
      creation of social security systems. The aim being to provide individual citizens with a legally documented
      entitlement to an income in old age and to thus make it economically attractive for a family to forego a large
      number of offspring.

   2.Scarcity-prices on what has up until now been considered "free" goods from the environment; The resulting
      process could be seen as a way of enforcing absolute limits on the exploitation of those resources whose
      exploitation has an international impact, or for those exhaustible resources which (like rain forests) should
      count as part of the global heritage.

 One possible disadvantage of global at-source taxation lies in its (possible) reliance on the institution of a supranational, possibly distributed, revenue service. Supranational taxation is confounded by two fundamental difficulties. The first is concerned with the definition and enforcement of a global (i.e. supranational) right to levy taxes. This may not be easily or quickly achievable, as it may require the creation of a global electorate. The latter step may have many advantages, and has, in the meantime, become recognized by many as being not only necessary, but well overdue. The second problem consists of the fact that monstrously large sums would, or at least might, accumulate in the planned funds. These funds, the use of which is at least in part subject to majority vote decisions, are always at risk of being secretly diverted from their intended use. It may not be easy to construct these institutions so that they are permanently protected against self-serving individuals or political or administrative coalitions. Yet, the credibility of the promise to provide old age security rests upon the long-term continuity and unassailable integrity of these institutions. Here one might consider using a consortium of competing service providers from the private sector to jointly manage the accumulated contributions as part of the model for financing the proposed pension schemes.

 The above-named basic requirements can also be realized by means of an international 'emission certificate' system, according to which tradable rights to the utilization of resources can be defined and allocated to the countries (again comp. w. [8]). The rights could, for instance, relate to the emission of hazardous materials, to population growth, and be coupled to the condition that all participating states set up an old age security system, which guarantees that those covered will receive an old age pension of a certain (nationally or culturally appropriate) minimum standard.

 All of the significant characteristics of an adequate globally-negotiated solution are thus achievable. As the developing countries will initially report levels of resource exploitation which are clearly lower than those of the industrialized countries, a trade in these certificates will ensue which will see the richer, industrialized states as
 payers and the poorer, developing countries as receivers of funds. According to this system, the income needed by developing countries for the maintenance of an old age security system could thus be achieved via a trade in emission certificates, instead of via at-source taxation.

 Because a certificate-based solution would place the responsibility for the establishment of social security systems at the level of the nation-state, this approach may be more readily accepted by them than would be a supranational solution based on at-source taxation. It could also be advantageous that these transfer payments
are made directly to the recipient states, rather than having first to be entrusted to the above-mentioned supranational institution. Although the misuse of funds is not thus excluded, this approach would reduce the risk, at the supranational level, of having funds illegitimately diverted to other uses; it would also facilitate the building
up of trust on the part of the recipient countries. Last but not least, the certificate solution would immediately allow a country to invest the funds to which it is entitled in beneficial development projects. This could, if accompanied by rational procedures, have a further dampening effect on population growth and, above all, it would play a decisive role in the catch-up process.

 Problems could, of course, develop due to considerable differentiation among countries in terms of cultural and human values, population size, resource status, existence of large CO2-sinks, etc. Such variability could also impede the implementation of further programs such as the world-wide provision of funds for the protection of forests, the financing of reforestation measures, or the transfer of technology in the framework of joint implementation measures. Here it would be feasible to think again of equalization solutions (discussed earlier) which work directly via global measures, rather than via a trade in certificates.

 Lowering material intensity

 Under the slogan of 'reducing material intensity' [28], advanced information and communication technologies (data highways, information super-highways, tele-services, etc.) and other technological developments are currently contributing to a reduction of the amount of energy and material resources (MIPS) consumed in the process of producing goods, services, and information (MIPS = material intensity per service-unit).

 It is hoped to lower material intensity (as measured relative to the most sophisticated techniques currently available) by a factor of 10 within the next 100 years. If such a reduction in material intensity is achieved by way of technological progress, it could lead to qualitative improvements in prosperity and economic growth; especially if it is combined with a total resource exploitation, which will by that time, hopefully, already be limited and falling [2, 3, 13, 26, 27, 29, 32, 33]. Telecommunication technologies could play a significant role in this, not only by replacing physical movement of people and goods (telework, teleshopping, telemedicine, etc.) but also by way of improving the management of what physical movement remains necessary (traffic management, road pricing,
 etc.).

 The lowering of material intensity is, in and of itself, not a new idea, but rather a classical by-product of technological progress. This process is dramatically noticeable as one follows the year-to-year changes in the fields of computer and communication technologies. Up until now, though, the leeway created through
 technological progress has as a rule been taken up, often even exceeded, by a compensating increase in activities called 'rebound effect' [16, 22]. Thus, the 150 million personal computers in world-wide use today represent
 10,000 times as many computer systems as there previously were mainframe computers, and the number of mainframes has climbed as well. At the same time, the performance of the modern personal computers has exceeded that of the original mainframes, and is smaller in size (unfortunately not in material intensity) by a factor
 of maybe 1,000. Precisely the latter has facilitated its proliferation and has caused a multiplicity of problematic consequences (more critical production processes, packaging and transportation expenditures, power consumption, etc.).

 If the rebound effect were to prevail over the whole technological spectrum, it would contradict one goal of sustainability: a substantial reduction in the consumption of non-renewable resources. It is therefore crucial that the reduction in material intensity be linked to the enforcement of an absolute requirement that total, world-wide resource consumption be lowered, either directly through global at-source taxation, or indirectly through husbanding resource use by means of the certificate solution described above. In this environment, the lowering of material intensity will, in spite of an ongoing reduction in resource exploitation, be a particularly effective vehicle to foster renewed growth (albeit in a different qualitative manifestation) in the total volume of goods, services, and
information. This, in turn, is a prerequisite for any realistic expectation that the population - and politicians - in the richer countries might give their approval to the proposed globally-negotiated solutions. If the latter do not require any per capita reduction in personal prosperity, they might produce substantial benefit for the populations in the developing countries, while at the same time protecting the environment.

The central role of information technology and the increasing economic pressure to find a globally-negotiated solution

 A particularly indispensable component of the kind of solution proposed are the information technologies [26]. Modern information technology, under the economic status quo, seems to be necessary for the lowering of material intensity, e.g. when it comes to replacing physical transport with the transportation of information.
 However, information technology is also a central element in global communication about existing necessities, the world-wide implementation of new ideas and solutions, the delivery of educational and medical services, as well as for individual contracting for global pension benefits.

 Thanks to information technology, there are today for the first time, globally comparable opportunities in view for individuals to participate in many fields of endeavour, at comparatively low costs. To put it more clearly: Never has it been less expensive than today to bridge the gap between rich and poor. International funding sources, such as the World Bank, should therefore be called upon to invest more extensively in the field of information technology. It must become our goal to establish a world-wide, satellite-based, communication network, to make multimedia workstations available world-wide, and to offer basic training courses everywhere, so that every community on earth has access to information, education and the telemarketplace. Courage and vision will be needed if these breakthroughs are to be realized and fundamental changes made in the world situation. Much of what has, thus far, been impossible (even inconceivable), is now within reach!

 Indeed, over and above establishing global access to information in the manner proposed, the above process will have the added effect of strengthening local capacity for self-help. With the help of these technologies, nearly all kinds of competence can be marketed world-wide at low transaction costs. While, on the one hand, this approach provides the conditions for the local generation of prosperity, on the other, it also creates world-wide economic pressure to arrive at globally-negotiated solutions. Were this NOT to happen, wage-depressing competition might first weaken, then attack and take over economically-attractive sectors and value-adding activities in the richer countries. The resulting, unregulated flow of wealth from the richer countries to the developing countries might well be much higher than the transfer of wealth which would have resulted from the more controlled and benign measures proposed herein.

 Economic pressures and market forces have always been the most effective forces for change. This also applies here. Actually, the more developed nations are already experiencing how the dynamic, fast developing countries are pressing them hard in the market place, and they increasingly recognize that many of these countries want to adopt those models of living and of economic activity which the more developed countries have long been enjoying. However, it is obvious to all parties that the lifestyles prevalent in the richer countries (based as they are on consumption and environmental destruction) cannot be exported to the developing world without destroying the world in the process.

 II. SCENARIOS, PERSPECTIVES, FINANCIAL ORDERS OF MAGNITUDE

 The scenario analysis presented below is intended to convey a sense of what the sought-for robust paths into a sustainable future might look like. It will also describe some concrete possibilities for parameters regarding the behaviour, under specific development scenario assumptions, of gross national product (GNP), population dynamics, and the utilization of material and energy resources. This is based on a simple systems analysis approach which has been applied to similar issues by others [1, 9, 17, 18, 19, 20, 23, 24]. The investigation here is into how the constraints described might be implemented in the form of concrete attempts at solutions, as well as into the extent to which the envisaged goals are attainable. The latter will be done, in part, by means of what
 has been referred to as 'optimistic modeling' [11, 12].

 The developed world

 The investigation assumes that, for instance via the appropriate pricing of resources or through taxes levied on the creation of waste, the annual growth of GNP in the developed countries can be limited to 0.75% until 2050 and to 0% thereafter. At the same time the per capita consumption should remain constant. All surpluses resulting from the 0.75% growth in GNP and the continuing reduction in population in the developed countries - to be more precise: from the reduction in total consumption, given a constant per capita consumption and a shrinking population - is to be transferred to the developing countries, until such time as the average of the global equivalent of the GNP is at the level of that in the MDRs. From that point in time per capita consumption in the MDRs and the LDRs will rise at the same rate, although this rate will be limited to 0.2% p.a., so as to achieve, over time, a reduction in resource exploitation to one tenth of that of today.

 In the event that, for political reasons, some per capita economic growth on the part of the developed countries is  desired or necessary, this can only be entertained, in the context of the model analyses completed, by means of a still more rapid shrinking of the population than the levels assumed above. Otherwise it will be at the expense of a slower pace of equalization in regional consumption opportunities, together with higher levels of resource
 consumption. A fertility rate of 1.8, defined in terms of children per adult female, has been assumed for the developed world. This will lead, by 2300, to a reduction in the number of people in the MDRs to 250 million. On account of the age structure in the MDRs, this reproduction rate will in the short term, that is until 2010, still result in a small increase in these populations. It should be mentioned, that in some countries, e.g. Germany, the reproduction rate has already sunk to 1.4 [35]. Thus, in the context of the strategy proposed herein, there exists a limited potential to tolerate a degree of migration into the MDRs.

 Less developed regions

 The model further assumes that, by means of appropriate pricing, or taxation, of resources and other accompanying measures, a self-generated average growth of GNP in the LDRs by 1% will be achieved annually until 2050, and will be reduced to 0.0% thereafter. Growth in these countries is augmented by a continuous
 income (transfer payments) from the MDRs. It will furthermore be assumed that the LDRs will invest a reasonable fraction of the funds received in this way, so that a positive "return-on-transfers" can be targeted in the form of an additional increase in the GNP of the LDRs. For the purpose of the model calculations, we have
 assumed a return-on-transfer of 0.1.

 Concerning the population dynamics for the LDRs, we essentially make use of the median variant of the United Nations Population Division [31]. This is already a relatively optimistic variant, which, in particular, assumes that by 2025 the world-wide fertility rate will have declined to replacement level (this represents a reproduction rate of about 2.06). This projection is combined with the further optimistic assumption that, via the establishment of internationally-guaranteed social security systems financed (in part) by transfer payments, a growing percentage of the population in the LDRs will successfully have been won over to the idea of accepting an internationally-guaranteed pension if they agree to limit the number of their offspring. For these populations, we have assumed a median reproduction rate of 1.5. The proportion of the population accepting such offers should grow over time. The model assumes, among other things, that, by the year 2050, 50% of young couples will have accepted this scheme.

 One should take note of the fact that, based on the assumptions underlying the projections of the United Nations, a constant reproduction rate of 2.0 will by this time have been reached world-wide anyway. The point is, therefore, that a part of the population is hopefully willing, given appropriate economic advantages, to accept distinctly fewer offspring. (The targeted low reproduction rate is still larger than the rate presently experienced in Germany). Figure 1 describes the resulting population development for the less developed countries. One can see that, due to the present-day demographic situation, there is an unavoidable increase in population, up to a maximum of about 7.5 billion people in the LDRs by 2050. Subsequently, however, given the assumptions made
 in the model, there is a steady decrease in this number, to about 850 million people in 2300.

 Figure 1: Population size in the more developed regions (MDRs) and in the less developed regions (LDRs)

 The total population will peak at approximately 8.5 billion around the year 2050. That is, the assumptions underlying the model imply a definite improvement, even relative to the median population projection made by the United Nations. This should be a strong motivation to proceed according to the scheme proposed here. Figure 1 demonstrates vividly that, even with the optimistic assumptions being made here, it will still take 100 years before the present population of 5.5 billion will again be reached. By the year 2170, three billion will have been reached, and finally, by 2300, the targeted figure of one billion.

 Figure 2: GNP and consumption per capita in the more developed regions (MDRs) and in the less developed regions (LDRs)

 A very important touchstone for the approach suggested here is the question of the development of per capita GNP in the poorer countries. Figure 2 shows that it is indeed possible to satisfy the requirement of a steady improvement in these countries, although the initial years, during which the population of the LDRs is expected to increase dramatically, will be especially critical. Only by means of a substantial investment, such as could be raised, for instance, from at-source taxation as described above, will it be possible to avoid a noticeable reduction in the living standards in the developing countries. After about twenty years, the GNP and supply of goods in the developing countries will begin to grow rapidly, although, to begin with, the difference between this and the constant consumption per capita in the richer countries will still be large.

 What is occurring here is the effect, in the early years, of the need to supply 7.5 billion people in the developing countries with an adequate income. The situation will rapidly get better as soon as this population begins to decline significantly. Around 2070 the relationship between the consumption levels of goods in the developing to that in the richer countries is already greater than two-thirds. This relationship will then already be more favourable than the spread which exists today both within and between individual G7 countries, and which is generally accepted as being socially tolerable. One generation later, then, given that the respective assumptions have been met, the per capita supply of goods in all regions of the world will be comparable. The, by then very compelling, reduction of the global population will, by 2125, have led to a doubling, in the richer (and thus all) countries, of the per capita GNP when compared with that in the G7 countries today.

 Material intensity and energy use

 The model assumes throughout (as a first approximation) that a linear relationship exists between the consumption of material and energy (as an approximation to MIPS) and GNP. This means that an expansion of GNP on the basis of today's technologies would be accompanied by a corresponding and proportional increase in consumption of material and energy. Moreover, it is assumed that due to technological progress a higher efficiency in resource utilization will be achieved over time. The assumed functional expression of this gain in efficiency is shown in Figure 3. It is assumed that a factor 10 reduction in material intensity will be achieved by 2100; in addition, it is assumed that already by 2030 we will have achieved a doubling in efficiency when compared with the situation today. The yardstick for this is Japan which, with regard to resource use/energy efficiency, outperforms the average developed country by a factor of 2.

 Figure 3: Material intensity or energy efficiency

 For MDRs, therefore, a long-term reduction in MIPS by a factor of 20 is assumed. As mentioned above,  appropriate pricing mechanisms (e.g. at-source taxation of resource use or the trading of emission rights certificates) are expected to ensure that rebound effects are avoided; i.e. that this technological progress is not
 translated into higher production and/or activity rates, or higher consumption on the basis of a higher resource  utilization, and therefore not into higher GNP. Quite to the contrary, it is expected that this technological progress will be combined, through the conscious decision of the world community, with moderate economic growth,  which will, from 2050 up to that point, have been in full retreat. According to the proposed scenario,  technological progress will function primarily to reduce material intensity, and not to raise GNP. Following  completion of the catch-up process, it is further assumed that the leeway made possible by the reduction in  population will only partly be used to increase the per capita GNP, but that it will predominantly be used to  further reduce energy utilization and resource consumption.

 Figure 4: Material use or energy consumption

 Figure 4 describes how, given the economic and demographic developments identified, the reduction in MIPS (as  per Fig. 3) suppresses material, that is to say, energy utilization. Also shown is how, thanks to increases in resource efficiency, the richer regions will after 2010 see a continuous lowering of resource exploitation; although, following 2110, this will be due solely to the reduction in total GNP (admittedly with a continuation of the slowly growing per capita GNP). It should be noted, as a particularly positive finding, that the approach chosen will not result in the developed countries experiencing a substantially increased resource exploitation, as was, for instance, feared by the German Bundestag's commission of enquiry "Protection of the Earth's Atmosphere"[6]. For the LDRs, the situation is similar. This is so in spite of the strong increase in the number of people until 2050, and the increase (though slow in the beginning) in per capita income, which is due on the one hand to a self-induced growth in GNP and on the other to the transfer from the MDRs. Here as well, an increased efficiency in resource
 use will, after 2030, overcompensate for all of these effects. Incidentally, from this point onward, the major part of global resource use will be occasioned by the (today) less developed countries.

 From 2090, if the assumptions hold, the utilization of material and resources will again increase slightly for a period of approximately 70 years. During this time period the GNP in the LDRs will still be growing, while resource efficiency (under the modeling assumptions made) will remain practically constant. The end of this
period marks the point in time at which the developing countries will have caught up with the MDRs with respect to the per capita GNP and from which the global leeway in terms of growth will predominantly be used to reduce resource exploitation. By 2240 resource exploitation will have been reduced to about one eighth of what it is today.

 As well, the requirement will have been met of a reduction, by 2050, in resource exploitation to one half of today's values, as was, for instance, formulated by the commission of enquiry ("Protection of the Earth's Atmosphere"[6]). According to what we know today, this reduction will be sufficient to prevent a global climatic catastrophe.

 Utilization of transfers in LDRs

 Sensitivity analyses carried out on the model shows a close correlation among several factors: the manner in which financial assistance is used in the LDRs (e.g. whether it is invested, with a resulting further increase in GNP, as opposed to being consumed completely), the length of time during which this assistance is required, the magnitude of the help (e.g. measured as a fraction of GNP in the MDRs), as well as the world-wide utilization of energy and resources.

 This rests primarily on the fact that the means used to raise the GNP in LDRs will shorten the catch-up process.
 Due to the mechanics of the model this has decisive consequences: Until such time as the per capita utilization in the LDRs has reached that of the MDRs, every increase in per capita GNP in the MDRs will lead to an increase in the differential between production and the (assumed constant) level of utilization. Such a per capita increase in GNP will be realized year after year because of the growth in GNP (by 2050) and the reduction in population (from ca. 2015). Because the difference between per capita GNP and per capita utilization will be skimmed off in the form of taxation on resource exploitation, or the purchase of 'environmental certificates', and ultimately made available to the LDRs, the assistance for developing countries and their GNP will grow year after year, until per capita income in the LDRs reaches the per capita utilization in the MDRs.

 In order to give an estimate of the extreme situation: If transfers should not generally contribute to the growth of GNP in the LDRs, then the catch-up process regarding the per capita utilization will require about 200 years, and the portion of funds to be raised by the MDRs will reach nearly three quarters of their GNP (see Fig. 5). This is obviously not a realistic scenario - it is limited to being a thought experiment.

 But it does make clear that the developed regions have every reason to press the developing countries to adopt a viable, investment-oriented use of the financial help received. With as little as a 10% yield on the transfer payments (that is, an increase in the level of the GNP by one tenth of the transfers received), the catch-up
 process will be reduced to about 80 years, and the maximum fraction of the MDR GNP needed for transfer stays under 50%. Assuming a yield of 25% on transfers (which is not unrealistic), would mean that the catch-up
 process would be completed in about 60 years, whereby the transfers will at no time exceed 40% of the GNP of the MDRs.

 Figure 5: Yield in transfer payments and required extent of transfers

 As much as a strategy calling for as rapid a catch-up rate as possible may be advantageous for the LDRs, so much so would it prove to be disadvantageous for the global energy and material resource balance. Because the faster the LDRs catch up, the higher will be their GNP, already during the critical phase in which their populations are still growing (exceeding even their current levels) and their MIPS are still high. The level of resource exploitation will also be correspondingly high during this time, although, in the long term, it is only minimally dependent upon the catch-up rate. Nonetheless, there is a conflict of interest, between protecting the environment and equalizing the living standards in the developing and developed countries, which can only be resolved by global negotiations and a balance of interests.

 Overall assessment

 Given the assumptions described, an analysis of the long-term scenario shows that it may be possible to reach a balance among all factors (i.e. a 'robust path'); and in such a way as to satisfy both the key requirements discussed in Part I and the corresponding specifications for robust paths.

 In the medium term, this path leads to a world-wide standard of living which is even higher that that currently enjoyed by the richer countries. While it also, at all times and in all regions, ensures that the prevailing relative standards of living are maintained, most people will see a clear improvement in their situation. Finally, it offers a readily visible reduction in the burden on the environment, e.g. primarily in terms of a decrease in material intensity.

If these positive developments are to be realized, a very critical transition period will have to be mastered over the next half century. This critical phase can largely be traced to the, now unavoidable, massive population growth in the LDRs to at least 7.5 billion people. It will be a major challenge to ensure that the living standards of this large fraction of the world's population do not decline and that, over and above this, a vision is offered which holds out the realistic hope that over time the chasm between the rich and the poor countries will disappear.  Without such a vision it will hardly be possible to engage the developing countries as partners in reaching the globally-negotiated solutions proposed herein.

 The model shows that, in combination with the other goals, this goal can best be reached if, for some time, the developed countries do not permit a further increase in their per capita consumption. The economic capacity of these countries is to be used, on the one hand, to ensure a constant per capita level in the provision of goods, and on the other, to support the less developed countries. This applies as well to the surplus expected to be generated by virtue of the falling population numbers in these countries. This surplus can be predicated on further automation of production processes, something which is technically possible and which, on account of the reduction in population, suggests itself in any case. The reduction in population numbers is, in this respect, not a problem, as already today we recognize that higher levels of production can, in fact must, be reached with a lower number of workplaces. This is one of the reasons for the growing unemployment that we see today in the G7 countries. The non-improvement in living conditions in the richer countries will, according to the scenario presented, be
 maintained until the year 2070, by which time the gap to the less developed countries will have been eliminated.

 Of critical importance to the approach being suggested here, is the requirement that a higher material intensity per service unit be also translated into a clearly more efficient and limited total resource utilization. The target is an increase in efficiency, by 2100, by a factor of 10 relative to the present state of energy efficiency in Japan, or by a factor of 20 relative to the average energy efficiency we have today in the G7 countries. If this factor of 10 increase in efficiency is achieved, then by 2300 a world population of about 1 billion could enjoy a standard of living twice as high as that enjoyed today by those living in the richer countries, and this with a level of resource exploitation which is less than one tenth of that today. This situation can, of course, only be reached if appropriate
political steps are taken in the direction described. This means especially that it is of great importance that future technological progress not be translated immediately into higher production, increased consumption, and more activity, but, on the contrary, that it be aimed strictly at a lowering of our demand for resources.

Highly stable adaptation, but: Why further growth in the MDRs would be a problem

Sensitivity analyses of the model show that the described developmental pathways reveal a high degree of stability; for instance, with regard to a lowering of the fertility rates in the LDRs, or to an improvement in resource use efficiency. The same goes for the assumptions made with respect to GNP, as long as the core elements of the proposed solution are maintained and followed. Included in these core elements is a restriction on the consumption of goods in the developed countries. Genuine growth in per capita consumption in the richer countries would be a big problem if it were not accompanied by a dramatic reduction in their birth-rates. As pointed out above, the reason for this is the fact that a higher per capita income in the richer countries ultimately induces still higher resource use. This would be a problem, in that the catching-up of the poor countries would be prolonged to reach this higher level of wealth, and would therefore result in yet higher total resource use. In spite of the assumed achievability of a high resource use efficiency, it could be that ultimately total resource exploitation might be reduced by only a factor of 2 (compared with today's rate), rather than by the hoped-for factor of 10; or even, that the rate could possibly increase again, which could precipitate a global crisis with a multiplicity of unpredictable consequences. This could ultimately lead to a chaotic disintegration of the world community.

The analysis suggests that, particularly within the next 20 years, we will be confronted with the task of balancing a complex burden of constraints and needs. If the correct solutions are not translated into political action, we might see the mutual amplification of dangerous trends in two directions: A clear growth of GNP and energy/resource use in the MDRs, and, simultaneously, a further strong increase in the number of people in the poorer countries.
 Together, these two situations could ratchet each other into crises and conflicts which would permanently exclude the kind of solutions being envisioned here.

The situation can, however, be managed if the right things are done in terms of policies, regulatory frameworks, etc. Where the developed countries must accept and enforce limits on resource use, the less developed regions must cope with the transition to small family sizes. In this way, global stability and comparable world-wide living conditions for all people, realized within a framework of sustainable development, appears to be achievable. The practical implementation of such a model solution demands many innovative systemic solutions, such as, for instance, the world-wide construction of pension and other social security plans.

 This analysis reveals that, following a difficult initial phase, during which the world's population will nearly double (by 2050), a process could be started which, over a 250-year period, would culminate in a factor 10 reduction in the global population, i.e. to about 1 billion. To this end, it will be important to create, with political means, the appropriate preconditions and incentive systems. The hoped-for reduction in population will depend essentially on how quickly the people in the developing countries can be motivated to accept a decidedly lower reproduction rate than heretofore. For this to occur will require the quick and accurate deployment of appropriate financial incentives and regulatory frameworks. Furthermore, it will be important to achieve a factor 10 reduction in material intensity, using technological progress, together with the enforcement of absolute (over time increasingly restrictive) limits on resource exploitation. In terms of this approach, it will be possible to achieve a world-wide reduction in resource exploitation, again by a factor of 10 - and if desired, even by a factor of 20. In spite of this, the approximately one billion people who would inhabit the earth in 2300 would be able to avail themselves of a standard of living decidedly higher than that attainable today in the G7 countries.

 A target population of one billion humans was chosen because a population of this size is compatible with the concept of a long-term, robust, and environmentally-sustainable development. A world population of this size could limit its material and energy needs almost completely to the exploitation of renewable resources. An economic system based on the strategies proposed herein would not only achieve stability and robustness, but would also justify the hope that the stability achieved could be maintained indefinitely. This would then give humankind sufficient time and breathing space during which to consider, without undue pressure, in which direction to proceed.

 The ideas proposed herein do not represent an actual path into the future, even if (for instance, in the context of EXPO 2000) a corresponding program of action for the 21st century were to be endorsed by the world community - ongoing developments will always lead to new opportunities, and to approaches which are, today, unimaginable.

 What is intended here, instead, is to portray, as a reference point, a scenario describing one possible robust pathway into the future; a path against which any purportedly better solution must demonstrate its superiority. It is also certain that pursuit of the path described here would at least lead to a stricter control over technological progress and further innovation, if only due to the fact that the global differentials in terms of social status would be smaller, and the resulting vested interest in the maintenance of the status quo, larger. In addition, this slowing down would itself increase stability, and allow future generations more time for reconsideration.

 Compared to the situation today, furthermore, a complete reversal of conditions would take place. It would only take a few decades before all significant indicators and trends point in another direction. These would include world population, resource exploitation, environmental pollution, climatic deterioration, overall consumption, and individual consumption. Following this path, a point would be reached in about 30-60 years when all relevant indicators would show improvement in a continuous and noticeable way. Simultaneously, a greater degree of control over technological progress, in the presence of an increasingly tolerable (i.e. smaller) differential in terms of social status, would manifest itself. One could well imagine that, under such conditions, human reflection and energy would be more and more concentrated on organizational and social innovations, for which there are no conceivable limits. There would also continue to be room for (socially-driven) scientific research and discoveries. At the same time, the per capita situation in all regions would see a permanent improvement, and the global situation would be more durable.

 Participation in the development of such a path into the future by means of a globally-negotiated solution should appear to be interesting and attractive for almost everyone. At the same time, it should be feasible simply to continue to pursue such a strategy until such time as a better alternative is found. The proposed robust path has the particular attraction of promising opportunities over a long time period, while also opening up immediate advantages. At the same time, it would develop as a point of reference for future (still better) possibilities, which could present themselves over the succeeding years and decades, especially when the time and space needed for reflection on solutions are made available by this path.

 The robustness of the path implies that minor variation of parameters, e.g. with regard to reproduction rate, may modify the time-frames but not its principal behaviour, thus leaving intact the chance for a relatively rapid  transition to a situation in which all parameters would become progressively better. The non-threatening variability
 implicit in such robustness would create the room necessary for political consensus-finding and trade-offs.

 Summary

 Towards the close of the second millennium, a critical and, as some think, uncontrollable situation has been reached which is related, particularly, to global overpopulation and environmental pollution; these being probably the most important consequences of technological 'progress'. At the same time, the effects of new technological  innovations, such as information processing, information superhighways, and multimedia, as well as the  deliberations and findings of important international conferences (e.g. Rio, Cairo, Copenhagen and Berlin) have been to create new options for action and to increase insight into the necessity for such action. Furthermore, we  have today a much better understanding of how such complicated transition processes might be managed socially [10, 20, 21, 23, 24, 25]. This will involve institutionalized top-down approaches and an appropriate synchronization of voluntary action, self-determination, equality, and a realization of the principle of subsidiarity on all local, regional, state and global levels. In addition, all this must be viewed against the backdrop of the theory of complex systems, in which the element of emergent systems behaviour, and the theoretical and empirical understanding thereof, will play a large role [14].

 This paper is intended to demonstrate, in the context of world problems and using a systems approach, that it may be possible to cope, in a peaceful and equitable manner, with the global challenges facing us as we enter the 21st century. It demonstrates that a permanent improvement for all people can be achieved by way of globally negotiated solutions. Besides appropriate measures to ensure accountability and enforcement, these will also require the careful combination of many different elements, some of which have been openly discussed, and some of which are, as yet, nearly taboo. The latter include, for instance, the use of economic incentives for lowering the world's population, global taxation on resource exploitation, processes of joint (global) implementation, efforts to avoid rebound effects due to technological progress, i.e. to bring about a global reduction in total material use, etc.

 The solution proposed is, of course, not offered as a definitive, future pathway, rather, it is intended to act as a practical reference point for possible future developmental directions. The corresponding measures will require substantial initial contributions from the developed countries; as much in the taking of positions with regard to critical questions - say, incentives for population reduction - as in the provision of the means for the world-wide financing and implementation of social security systems. It is suggested herein that the latter might be done on the basis of global at-source taxation on resource exploitation, and/or certificates to control environmental pollution.
All this can, cost-wise at least, and on the level of these orders of magnitude, be coped with; especially for the richer countries, this approach probably represents by far the most affordable way in which to sustain, in the long run perhaps even to improve, the quality of life of their own citizens. Beyond this, the proposed path opens into a future which provides greater fairness with regard to the world-wide distribution of opportunities for survival and prosperity, which creates fewer ongoing necessities for change, and which protects nature and the environment. This path could really lead to a more humane world, and support a generally-climbing quality of life.

REFERENCES

   1.Arnaszus, H., W.B. Clapham and R. Pestel: On the Scenario Approach to Simulation Modeling of
      Complex Policy Assessment and Design. IIASA RR, Laxenburg, 1980.
   2.Brown, L.R. et al.: Saving the Planet - How to Shape an Environmentally Sustainable Economy. W.W.
      Norton & Company, New York, 1991.
   3.Dieren, W. van (ed.): Mit der Natur rechnen: Der neue Club-of-Rome-Bericht: vom Bruttosozialprodukt
      zum Ökosozialprodukt. Birkhäuser, Basel-Boston-Berlin, 1995.
   4.Ehrlich, P.R.: Population Bomb, new re. ed. (Orig.), Ballantine Books, Incorporated, 1975.
   5.Ehrlich, P.R. and Ehrlich A.: The Population Explosion, Touchstone Bks., Simon & Schuster Trade, 1991.
   6.Enquetekommission "Schutz der Erdatmosphäre" des Deutschen Bundestages (ed.): Mehr Zukunft für die
      Erde. Nachhaltige Energiepolitik für dauerhaften Klimaschutz, Bonn, 1995.
   7.Eriksson, A.W. (ed.): Population Structure and Genetic Disorders. Proc. of the 7th Sigfred Juselius
      Foundation Symposia, LC 80-40143, Academic Press, 1981.
   8.Ewers, H.-J. and C. Hassel: Dauerhaft umweltgerechtes Wirtschaften: Entwurf für die künftige Ordnung
      von Wirtschaft und Gesellschaft. In "Welt im Wandel - Herausforderungen an Wissenschaft, Wirtschaft
      und Politik" (K. Morath, ed.), Frankfurter Institut - Stiftung Marktwirtschaft und Politik, Bad Homburg,
      59-87, 1996.
   9.Forrester, J.W.: World Dynamics. Wright-Allen Press, Cambridge, USA, 1971.
  10.Gabor, D. and U. Colombo: Beyond the Age of Waste. Report to the Club of Rome. DVA, Stuttgart,
      1976.
  11.Greiner, C. and F.J. Radermacher: Reliable Data Concerning Factors of Critical Significance to the Living
      Conditions of Human Beings - An "Optimistic" Modeling Approach. In: Cybernetics and Systems 94 (R.
      Trappl, ed.), pp. 919-926, World Scientific, Singapore, 1994.
  12.Greiner, C., F.J. Radermacher, J. Edrich and T.M. Fliedner: Monotonic Structures as Basis for Reliable
      Predictions Concerning Factors of the Human Habitat. In: Informatik für den Umweltschutz (L.M. Hilty et
      al., eds.), pp. 435-442, Metropolis-Verlag, Marburg, 1994.
  13.Hauff, V.: Unsere gemeinsame Zukunft. Der Bericht der Brundtland-Kommission, München, 1987.
  14.Kelly, K.: Out of Control. Addison-Wesley, Reading, Mass., 1994.
  15.Kommission für Humanökologie 2 (ed.): Die Bevölkerungsentwicklung und ihre Auswirkungen auf die
      Umwelt. Austrian Academy of Sciences, 1990.
  16.Lem, S.: Summa Technicae. Suhrkamp, Frankfurt a.M., 1981.
  17.Meadows, D.L. et al.: The Limits to Growth. Universe Books, New York, 1972.
  18.Meadows, D.L. et al.: Beyond the Limits: Confronting Global Collapse, Envisioning a Sustainable Future.
      Earthscan, 1992.
  19.Mesarovic, M. and E. Pestel: Mankind at the Turning Point. Hutchinson, London, 1974.
  20.Mesarovic, M., E. Pestel and R. Pestel: An interactive decision stratum for the multilevel world model.
      Futures, 357-366, August 1973.
  21.Müller, N.: Civilization Dynamics. Vol. I and II. Athenaeum Press, Newcastle upon Tyne, 1991.
  22.Neirynck, J.: Der göttliche Ingenieur, Expert Verlag, Renningen, 1994.
  23.Pestel, E. et al: Deutschland-Modell. Fischer, Frankfurt a.M., 1980.
  24.Pestel, E.: Beyond the Limits to Growth. Report to the Club of Rome. Universe Books, New York, 1989.
  25.Radermacher, F.J.: Menschenbild und Überbevölkerung. In: Wissensverarbeitung und Gesellschaft, Band
      4, Universitätverlag Ulm, 1992.
  26.Radermacher, F.J.: Und sie bewegt sich noch - Die Welt im Jahr 2050. Keynote speech on the occasion
      of the Rotary District Conference in Ulm, May 27, 1995; DER ROTARIER Heft 4, 21-33, 1996
  27.Renn, O.: Ein regionales Konzept qualitativen Wachstums: Pilotstudie für das Land Baden-Württemberg.
      Akademie für Technikfolgenabschätzung in Baden-Württemberg, Stuttgart, Technical Report No. 3, 1994.
  28.Schmidt-Bleek, F.: Wieviel Umwelt braucht der Mensch?, in: MIPS - Das Maß für ökologisches
      Wirtschaften. Birkhäuser, Berlin, 1994.
  29.Stähler, F.: Some Reflections on Multilateral Environmental Agreements. Kiel Working Paper No. 647,
      Kiel, 1994.
  30.UNDP: Human Development Report 1994. Oxford University Press, New York, 1994.
  31.United Nations Population Division: Long-Range World Population Projections: Two Centuries of
      Population Growth, 1950-2150. UN, New York, forthcoming, executive summary, 1995.
  32.Weizsäcker, E.U. von: Erdpolitik: ökologische Realpolitik an der Schwelle zum Jahrhundert der Umwelt.
      Wiss. Buchges., Darmstadt, 1990.
  33.Weizsäcker, E.U. von und J. Jesinghaus: Ecological Tax Reform. Policy Proposal for Sustainable
      Development. Zed Books, London, 1992.
  34.Weizsäcker, E.U. von, A.B. Lovins und L.H. Lovins: Faktor vier. Droemer Knaur, München, 1995.
  35.World Bank: World Development Report 1993. Oxford University Press, New York, 1993.
  36.World Resource Institute: World Resources 1992-3. Oxford University Press, New York, 1992.

 APPENDIX: MODEL OVERVIEW

 Assumptions and Initialization Data

 The following overview of the model considers population dynamics, resource and energy use, etc., under certain
 modelling and scenario assumptions.

 As indicated above, the model makes a distinction between the more developed regions (MDRs) of the world
 and the less developed regions (LDRs). The time horizon of time t for the simulations is limited . The following
 data are used for the analyses:
 

 Human Development Report, 1994,      MDRs     LDRs    Units
 UNDP

 GNP per capita                         14,920     880 US-$
 Population                                  1.2     4.2 billions
 Fertility rate                                2.0     3.8 children per adult female
 Energy consump. per capita               4840     550 kg oil equivalents
   

Demographic Sub-model

 Population Growth

 A females-only model, taking into account population age composition, is used. The population is divided into n
 + 1 age groups, each of length k. The number in age group at time t is and the vector

 (1)  specifies the age structure; (default values: k = 10, n = 8). expresses the number of babies born in the 
        interval,  which equals k years. The discrete model of demographic growth closed to migration is as follow:

 (2)  whereby denotes the average number of female babies born to a woman in age group and is the probability
        to survive from age group to .

 This discrete model of demographic growth can also be expressed more compactly in matrix form X(t+1)= P  X(t), where

 (3)  denotes the total number of females living in a specific region at time t. This model was adapted to two
        regions:  MDR and LDR, whereby the population vectors are denoted X(t) for MDR, Y(t) for LDR.
       Although the patterns of the age specific fertility rates where assumed to be similar, the total fertility rates
       were assumed to be different.

 Migration and small family sizes

 In the scenario, the region MDR is closed to migration. However, there is a shift in the fertility rates from 2.1 to
 1.8 in LDR depending upon the proportion of people in LDR who end up following the "robust path" of family
 size reduction.

 A logistic curve is used to describe the assumed relationship of the acceptance level over time and the further
 shrinking of the family sizes.

 (4)  The parameters a,b,c were fitted in order to satisfy the following conditions:

 (5)  Denoting the fertility rates of the stable path with a modification of equation (2) for the developing countries
        results as follows:

 Figure 1 illustrates the result of a simulation run for the population size for MDR and for LDR.

 Economic Growth

 For economic considerations, the world was divided into 2 regions, MDRs and LDRs. Let be the GNP growth
 rate in the MDRs and the GNP growth rate in the LDRs.

 (6) The evolution of the GNP for both regions is described by:

 (7) is a measure of the yield of the transfer payments received. Figure 5 shows the relation of this parameter to
       the extent of required transfers over time. As an indicator of well-being, a domestic use (D) is introduced that
       includes the regions' consumption, investment, and governmental consumption levels.

 (8)  The transfer is calculated so that the given domestic use per capita does not decrease, hence

 (9)  Figure 2 shows the evolution of these entities.

 Energy Consumption

 It is assumed that the energy consumption e(t) as described in Fig. 4 for a region is proportional to its GNP, and
 that this is reduced over time by an efficiency coefficient eff (t):

 (10)  To describe the increase in energy efficiency a sigmoidal growth model is used, which is not symmetrical
         about the point of inflection. At the beginning the increase is linear, at the end logarithmic. The following
         ordinary differential equation describes these assumptions:

 (11)  Integrating 11 gives:

 (12)  The parameters were fitted in such a way that the following efficiency coefficients hold: eff(2000) = 1,
         eff(2030)  = 0.5, and eff(2100) = 0.05 (see also Fig. 3).
 

* Authors' Organizations

(a) FAW - Research Institute for Applied Knowledge Processing, Ulm, Germany
(b) School of Health Information Science, University of Victoria, Canada
(c) WHO - Chairman of the Global Advisory Committee on Health Research (ACHR) -
                  Institute for Occupational and Social Medicine, University of Ulm, Germany
(d) Turku School of Economics and Business Administration, Finland Futures Research Centre, Turku, Finland
(e) Frankfurt Institute for Economic and Public Policy Research (Frankfurter Institut), Bad Homburg, Germany
(f) European Commission, Brussels, Belgium
 

* Presentation History and Current Internet Links (Summer 1998)

   Paper presented by Heiner Benking on the XIV World Conference of World Futures Studies Federation (WFSF), 25-30 July 1995, Nairobi, Kenya. This work can be seen in the context of the conference "Welt im Wandel", Frankfurter Institute, 25-26 July 1995, Frankfurt, Germany, where a paper with similar scope and  content was presented by Prof. Dr. Dr. Radermacher the day after the Nairobi presentation in the German/European environment, and in view of the EXPO 2000 activities and  scope. The theme of "Welt im Wandel" was borrowed from an exhibition called "GLOBAL CHANGE - Welt im Wandel, Challenges to Sciences and Politics", May  1990 in the German Chancellery in co-operation with the White House Conference on Global Change. The author (Heiner Benking) had helped with the design and production of some posters and elements for the GLOBAL CHANGE exhibition (see some poster boards and the exponat "Blackbox Nature"- a documentation on the WWW web is in preparation) and see the work of constructing a steering or "cybernetes" - cyber decision space,  as a digital decision room and as a continuation of the work to embody and visualise complex issues, share and start the dialogue about the complexity, proportions and consequences of decision processes. See http://newciv.org/cob/members/benking/sitspace.html
    This paper in the Economy and Futures, Section IV of the WFSF, Nairobi, needs to be seen in the context of the second presentation at the WFSF, in the Eco-Philosophy and Environmental Ethics, Section III , titled "THE OPTICS OF ETHICS", by Heiner Benking. Unfortunately the conference president of the WFSF, Nairobi and president of the World Philosophical Society H. Odeera Oruka was killed shortly after the conference. In the resulting turmoil, problems occurred in documenting this most extraordinary event organised by the WFSF President Penttii Malaska. Unfortunately only the "ROBUST PATHS" paper was published, and not the perhaps even more central and critical paper (in the view of the author): "THE OPTICS OF ETHICS - how to communicate complex issues, how to share common frames of references and understanding across cultures and domains-".
    It is made available at http://newciv.org/cob/members/benking/opto.html and is presently updated in conjunction with a paper presented by the author at the conference organised by Principle Responsibility - philosopher Hans Jonas. The loss of Odera Oruka is a loss to humankind - he was not only specially gifted but able to include traditional ethical viewpoints. In his rememberance I strongly recommend the book Philosophy, Humanity and Ecology - Philosophy of Nature and Environmental Ethics, ISBN 9966-41-086-4
    For details, the author also recommends: CAPACITY TO GOVERN - Six summary points as developed with Yehezkel Dror Club of Rome ceptualinstitute.com/genre/benking/governance.htm#UN and the key-note on hehalf of the Director of UNEP-RONA Dr. Noel Brown "Proposing a Conceptual  Superstructure", FIG XX, Melbourne, March 5-12, 1994, see: ceptualinstitute.com/genre/benking/melbourne.htm for a review of the AGENDA 21 process and how technical perspectives could help to communicate Global Issues. In this respect the work of a colleague and friend of the author should be mentioned, Anthony Judge, UIA. He was involved and proposed to design the AGENDA 21 back in 1992 as a systemic document ! Which means that issues are not listed and in this way presented out of context, but in a framework, which is deep and coherent. See recent work of Judge in the INFO 2000 programme to display issues or problems with virtual displays, which helps to map and wrap "checks and balances" onto a solid tensegrity body. See http://www.uia.org/uiademo/vrml/vrmldemo.htm
 
    A revised  version of the ROBUST PATHS paper also appeared in: Malaska, P. (ed.): People and Work,  Research Reports 8 "Work in the Information Society", Finnish Institute of  Occupational Health, Helsinki, Finland, 20-22 May 1996