The scenarios point to both risks and
opportunities in the future. Of particular
significance are the risks of crossing
thresholds, the potential of reaching turning
points in the relationship between people
and the environment, and the need to
account for interlinkages in pursuing a
more sustainable path.

Chapter 9: The Future Today - Towards 2015 and Beyond

Main messages

This chapter builds on previous chapters by exploring how current social, economic and environmental trends may unfold along divergent development paths in the future, and what this might mean for the environment, development and human well-being. It presents four scenarios to the year 2050, using narrative storylines and quantitative data to explore different policy approaches and societal choices at both global and regional levels. The main messages of the scenarios – Markets First, Policy First, Security First and Sustainability First – are:

There is a need to address interlinkages among numerous environmental issues, such as air and water pollution, land degradation, climate change, and biodiversity loss. There is also a need to link environment with development issues, such as extreme poverty and hunger, implementation of the MDGs, and addressing human vulnerability and well- being. This addresses one of the statements in Our Common Future, which says “the ability to choose policy paths that are sustainable requires that the ecological dimensions of policy be considered at the same time as the economic, trade, energy, agricultural, industrial and other dimensions – on the same agendas and in the same national and international institutions.”

For a range of indicators, the rate of global environmental change slows or even reverses towards the middle of the century. In all scenarios, the rates of cropland expansion and forest loss steadily decline over the scenario period. The rate of water withdrawals eventually decreases in all scenarios, except Security First. Some scenarios also show a slackening in the tempo of species loss, greenhouse gas build- up, and temperature increase. The slowing down of these global indicators is due to the expected completion of the demographic transition, the saturation of material consumption, and technological advances. This slowing down is important because it gives us hope that the society and nature can more successfully catch up to the pace of change and adjust to it before experiencing many negative consequences.

Despite a possible slowing down of global environmental change, the peak rate and end point of change differs strongly among scenarios. The higher the rate of change, the greater the risk that thresholds in the Earth system will be exceeded in the coming decades, resulting in sudden, abrupt or accelerating changes, which could be irreversible. Differing rates of change lead to very different end points for the scenarios. Under Markets First, 13 per cent of all original species are lost between 2000 and 2050 as compared to 8 per cent under Sustainability First. The range in 2050 for atmospheric CO₂ concentration is over 560 ppm in Markets First as compared to about 475 ppm under Sustainability First. It is expected that the risk of exceeding thresholds increases with a higher level of change, and that this change could be sudden rather than gradual. For example, the GEO-4 scenarios showing the fastest rate of increase in fish catches are also accompanied by a significant decline in marine biodiversity, leading to a higher risk of fisheries collapse by mid-century.

Investing in environmental and social sustainability does not impair economic development. Scenarios, including increased investment in health, education, and environmentally benign technologies result in equally large and more equitably distributed economic growth on a per capita basis in most regions as those that do not. The levels of GDP per capita are particularly higher in Sustainability First and Policy First than Markets First and Security First in nearly all of the currently less developed regions.

Relying on the market alone is unlikely to achieve key environmental and human well-being goals. The extreme emphasis on markets in Markets First results in significant increases in environmental pressures and only slow down advances in achieving social targets. Alternatively, the increased levels of investments in health, education and the environment, along with increased development assistance and new approaches to lending in Policy First and Sustainability First make for significantly faster progress, without sacrificing economic development in most regions.

Greater integration of policies across levels, sectors and time, strengthening local rights, and building capacity help achieve most environmental and human well-being goals. Additional action under Sustainability First – integrating governance across levels, sectors and time, strengthening local rights, and building capacity – lead to greater improvements and slower degradation than in Policy First. Much of this is related to the increased ownership of the issues by the broader public, and the greater legitimacy of policies. Interaction between global and regional processes suggests that concentrating environmental governance at one scale is unlikely to result in appropriate responses to environmental problems with their feedbacks.

Both trade-offs and synergies exist in the efforts to achieve key environmental and human well-being goals. Competition for land is likely as a result of competing goals: the production of biofuels to achieve climate goals, the production of food to achieve food security, and designation of areas for biodiversity. Competition can be expected for water use between the provision of adequate supplies for human activities and the maintenance of adequate in-stream flows for the integrity of aquatic ecosystems. Furthermore, achieving these goals may require the acceptance of rates of economic growth, as presently measured, in the currently highly-developed countries that, while still significant, are lower than would be the case otherwise. Key synergies result from policies that address the drivers of many of the problems. These include investments in health and education, particularly of females, which directly achieve key human well-being goals, and help to address current and future environmental goals by improving environmental management and reducing population growth.

The diversity and multiplicity of trade-offs and opportunities for synergy increases complexity for decision-makers, requiring new and adaptive approaches. This complexity should not be ignored. It, however, points to the need for innovative approaches for exploring the options for action to address the intertwined environmental and developmental challenges the world faces.

Introduction

What lies ahead? Which of the current environmental, social and economic trends will continue, and which will see dramatic shifts? What will this mean for the environment and human well-being, particularly the most vulnerable ecosystems and groups in society? What will this mean for individual sub-regions and regions, and, collectively, at the global level? Finally, what role can society play today in shaping and sustaining our common future?

It is unlikely that most trends would continue unabated for decades without changing course. (Credit: Munyaradzi Chenje)

To imagine what might happen over the next half- year, much less the next half-century is daunting. To imagine the future across national, sub-regional, regional and global levels is even more complex. Given that many processes are already in motion as a result of past decisions, it may be relatively easy to visualize certain trends continuing in the short-term. Still, history shows that much can change, expectedly or unexpectedly, over short periods, and it is unlikely that most trends would continue unabated for decades without changing course. History also shows that some policy decisions take many decades to unfold, for example, sustainable development and mainstreaming the environment. Both have been on the international and national agenda for the 20 years since the report of the World Commission on Environment and Development, Our Common Future, was published, but increasing their uptake remains as urgent today as it did then.

Choices made today on issues of environment for development may only begin to reveal their effects after decades. A major challenge is, therefore, to present stories that make sense in both the short- and long-term. This includes keeping one eye on the status of upcoming milestones. For example, the 2010 Convention on Biological Diversity target to significantly reduce the current rate of biodiversity loss at the global, regional and national levels, and the 2015 internationally agreed targets of the Millennium Declaration, such as those on water and sanitation. At the same time, it is necessary to look further ahead in time to more distant goals, such as stabilizing the levels of greenhouse gas concentrations in the atmosphere.

Based on both regional and global consultations and processes involving many stakeholders, including governments and other organizations, this chapter explores these and other issues by considering the future through the lens of environment for development. The four scenarios consider the priority and cross-cutting issues discussed in the preceding chapters.

They focus on the implications of various actions, approaches and societal choices at regional and global levels for the future of the environment and human well-being. Each scenario outlines a pathway into the future up to the year 2050, shaped by divergent assumptions about these actions, approaches, and choices. Each looks at who is making the key decisions (the dominant actors), how these decisions are made (the dominant approaches to governance) and why these decisions are made (the dominant priorities). The nature and the names of the scenarios are characterized by the theme that dominates the particular future envisioned, that is what comes first. Briefly, the scenarios assume the following:

• Markets First: the private sector, with active government support, pursues maximum economic growth as the best path to improve the environment and human well-being. Lip service is paid to the ideals of the Brundtland Commission, Agenda 21 and other major policy decisions on sustainable development. There is a narrow focus on the sustainability of markets rather than on the broader human-environment system. Technological fixes to environmental challenges are emphasized at the expense of other policy interventions and some tried-and-tested solutions.

• Policy First: government, with active private and civil sector support, initiates and implements strong policies to improve the environment and human well-being, while still emphasizing economic development. Policy First introduces some measures aimed at promoting sustainable development, but the tensions between environment and economic policies are biased towards social and economic considerations. Still, it brings the idealism of the Brundtland Commission to overhauling the environmental policy process at different levels, including efforts to implement the recommendations and agreements of the Rio Earth Summit, the World Summit on Sustainable Development (WSSD), and the Millennium Summit. The emphasis is on more top-down approaches, due in part to desires to make rapid progress on key targets.

• Security First: government and private sector compete for control in efforts to improve, or at least maintain, human well-being for mainly the rich and powerful in society. Security First, which could also be described as Me First, has as its focus a minority: rich, national and regional. It emphasizes sustainable development only in the context of maximizing access to and use of the environment by the powerful. Contrary to the Brundtland doctrine of interconnected crises, responses under Security First reinforce the silos of management, and the UN role is viewed with suspicion, particularly by some rich and powerful segments of society.

• Sustainability First: government, civil society and the private sector work collaboratively to improve the environment and human well-being, with a strong emphasis on equity. Equal weight is given to environmental and socio-economic policies, and accountability, transparency and legitimacy are stressed across all actors. As in Policy First, it brings the idealism of the Brundtland Commission to overhauling the environmental policy process at different levels, including strong efforts to implement the recommendations and agreements of the Rio Earth Summit, WSSD, and the Millennium Summit. Emphasis is placed on developing effective public-private sector partnerships not only in the context of projects but also that of governance, ensuring that stakeholders across the spectrum of the environment-development discourse provide strategic input to policy making and implementation. There is an acknowledgement that these processes take time, and that their impacts are likely to be more long- term than short-term.

Each scenario outlines a pathway into the future up to the year 2050, shaped by divergent assumptions about actions, approaches, and choices. (Credit: Munyaradzi Chenje)

As is the case for most scenarios, these four are caricatures in that the real future will include elements of all four and many others. Furthermore, scenarios are not predictions, nor should they be taken as the most likely of the myriad of possible futures. At most, they paint pictures of a limited number of plausible futures, based upon a coherent and internally consistent set of assumptions about choices by key actors, the progression of other social processes, and underlying system relationships ^[2]. Finally, in any scenario exercise, there are inherent uncertainties related to both the current state and the behaviour of human and ecological systems. Thus, individual scenarios represent conditional projections based upon assumptions about the underlying human and ecological systems, as well as the actions, approaches, and choices noted above ^[3].

Despite these challenges, the scenarios presented here provide valuable insights for decision making today. The narratives and numerical elements complement each other, reflecting the approach of most recent scenario exercises ^[4]. The Technical Annex at the end of this chapter briefly reviews how the scenarios were developed.

Fundamental Assumption behind the Scenarios

Scenario development is traditionally characterized by identifying key drivers and critical uncertainties surrounding their future evolution, making assumptions about how these critical uncertainties will evolve, and exploring the broader implications of these developments. In the GEO-4 conceptual framework, the key drivers of environmental change include: institutional and socio-political frameworks, demographics, economic demand, markets and trade, scientific and technological innovation, and value systems. This list is much the same as used in GEO-3, as well as in the Millennium Ecosystem Assessment ^[5] and other recent scenario activities.

Behind these different drivers are the decisions by key actors, such as whether to act reactively or proactively with respect to environmental change. In addition, assumptions are made about key system relationships, such as the precise sensitivity of the climate system to increased concentrations of greenhouse gases (GHGs), or the exact effect of a reduction of crop yields on the health of some groups. From this perspective, the evolution of many of the drivers, as well as the pressures, state and impacts, are themselves part of the unfolding of the scenarios and not a priori assumptions. As such, this presentation of the assumptions underpinning the GEO-4 scenarios differs somewhat from similar exercises.

Fig 9.1 Strength of investments in opportunities to reduce vulnerability in human-environment systems and improving human well being.

Figure 9.1 and Table 9.1 summarize the assumptions underpinning and distinguishing the four scenarios. Table 9.1 considers a series of questions grouped by the key drivers in the GEO-4 conceptual framework. Using the set of opportunities for reducing vulnerability in human-environment systems and improving human well-being presented in Chapter 7, Figure 9.1 illustrates the strength of the investments targeted to these opportunities. Together, these provide more specific information, building on the assumptions provided in the Introduction. They highlight the general character of the scenarios; differences will certainly exist across regions and over time in any given future, just as they do today.

Table 9.1 Key questions related to scenario assumptions.

Table 9.1 Key questions related to scenario assumptions, continued.

Other than for trade, technology and resource access, investments are assumed to be lower in Markets First than in either Policy First or Sustainability First. Sustainability First is distinguished from Policy First by the added emphasis placed on equity and shared governance, particularly at the local level. Not surprisingly, the overall level of investments in these opportunities is assumed to be the lowest in Security First, although this does not rule out significant efforts by particular groups. Each scenario provides challenges and opportunities in the way society addresses environmental issues.

With respect to assumptions about other aspects of the current state and the behaviour of human and ecological systems, key system relationships, such as the levels of environmental robustness and the physical availability of natural resources, are held constant across the scenarios. While it is clear that there is significant uncertainty about many of these factors, varying them across the scenarios would complicate efforts to understand the impacts of the different assumptions about individual and societal choices, which is the primary focus of this exercise.

Snapshots of Four Futures

Looking back to 1987, it is clear that many dramatic changes have occurred in the world. Not surprisingly, it is possible to see developments and trends during this period that support each of the four pathways to the future, as well as other possible futures.

To some, increased international cooperation on climate change issues is an example of the benefits that high-level policy actions can offer for environmental protection. The entry into force of the Kyoto Protocol, the development of global regulations enabling carbon capture technologies and emissions trading, the implementation of national strategies to reduce GHG emissions, and the adoption of various multilateral environmental agreements to address a diversity of challenges, all point to the success of negotiated agreements. The establishment of biodiversity targets for 2010 under the Convention on Biological Diversity provides another example of international agreement on common goals. Recent policy reforms at the regional level have also seen greater integration of policies, sectors and standards across groups of countries, for example, with respect to water management and agricultural practices in the enlarged European Union.

Others are encouraged by what they see as a continued shift in favour of a stronger social and environmental agenda among both governments and citizens. Concerted efforts to promote universal primary and secondary education, and mainstreaming of environmental and social adjustments to GDP figures represent two movements in this direction. The adoption of internationally agreed targets of the Millennium Declaration reflects commitment across the world to address sustainable development challenges. At the local level, a growing level of grassroots and civil society engagement directs energy and attention towards livelihood issues with both local and global relevance, including fair trade.

Less encouragingly, some see an unsettling pattern of conflict and entrenched interests playing out both in and between nations in today’s world, characterized by increasing inequality and social isolation. Heightened security measures that restrict human movement and increase military expenditure lend weight to this view of the world. Instability and conflict have a critical effect on quality of life for millions. Certain international trade policies protect the existing balance of power through increased tariffs and protectionism, while local enclaves can be seen in the form of highly-secure housing developments in cities.

The market economy is seen as the dominant paradigm for fostering growth and human well-being, with diverging opinions about its success. Proponents see the continued rise in oil consumption and prices as fuel for considerable growth, while skeptics focus on its negative social and environmental consequences. Some argue that the role of governments is tilted in favour of economic objectives, even while it may be shrinking overall in the face of increasing corporate influence in policy decisions and trade agreements.

These varied aspects of the recent and today’s world exert very different pressures on human decisions and actions, with implications for the environment and human well-being. A continuation or change in any of these patterns could have a pivotal influence on major issues at local, regional and global levels. Government leadership, market incentives, protectionist motives or unconventional approaches could mean the difference between marked improvement and steady decline on such prevailing environmental concerns as freshwater quality and availability, land degradation, biodiversity conservation, and energy use with its associated GHG emissions and climate change effects. Socially, these different approaches could translate into radically different situations regarding equity and distribution of wealth, peace and conflict, access to resources and health services, and opportunities for political and economic engagement.

Which of these trends will be the most dominant over the next decades? This is open to debate. In the end, the answer will likely differ across regions and over time. This section presents snapshots of the four futures considered in this chapter.

Markets First

The dominant characteristic of this scenario is the tremendous faith placed in the market to deliver not only economic advances, but also social and environmental improvements. This takes several forms: an increased role of the private sector in areas that were previously dominated by governments, a continued movement towards freer trade, and the commoditization of nature. A key question it poses is: how risky is it to put the markets first?

Most regions see a significant increase in the privatization of education, health and other social services, extending even to the military, as governments seek to achieve economic efficiency and reduce their financial burden. Research and development becomes increasingly dominated by private organizations. Assistance to developing countries moves even further in the direction of direct investment and private donations, with little change in official development assistance.

International trade accelerates as the World Trade Organization grows. Although no global free trade zone is achieved, pre-existing regional free trade agreements are strengthened and new ones emerge, for example, in South Asia (SAFTA). In addition international economic cooperation grows, both within and among regions. Growing South-South cooperation, such as between Asia and the Pacific, Africa, and Latin America and the Caribbean, stands out in this regard.

Efforts to increase privatization and trade are accompanied by an increase in measures to put prices on ecosystem services and turn them into commodities. Although this forces people to better recognize the value of these services, it is not the primary intent of these efforts, which are driven more by ideological aims. The commoditization and economic exchange of goods such as water, genetic material, and traditional knowledge and culture, dramatically increases. With these changes, the size of the “commons,” both globally and locally, shrinks significantly.

Formal environmental protection progresses slowly, as it competes against efforts to increase economic investment and expand trade. The Kyoto Protocol is only ineffectively enforced and there is no significant international follow-up after its expiry in 2012. Multilateral environmental agreements generally defer to trade and other economic agreements when they come into conflict.

The effects of these choices are seen in many aspects of society and the environment. The growing economy, with its seemingly insatiable demand for energy, the continued dominance of fossil fuels, and the limited efforts to reduce emissions result in continued rapid growth in equivalent CO₂ emissions for the world as a whole.

In terms of regional air pollutants, the pattern varies by region as increasing incomes bring calls for greater controls. In regions such as North America and Western Europe, reductions continue, although these slow somewhat over time. Regions where economic growth reaches sufficient levels see increases followed by declines, particularly for those pollutants most detrimental to human health, such as particulates and SO₂. Other regions, such as parts of Latin America and the Caribbean, Africa and Central Asia continue to see rises in pollutant levels.

A number of forces, most notably the increased demand for food, freer trade, the phasing out of agricultural subsidies, technological advances, the growth of cities, and increased demand for biofuels affect land use in quite different ways across the world. Globally, there is actually a slight decline in land devoted to food crops, but a rise in grazing land. The total forest area declines, but starts to recover later in the period, albeit with a continued slight decline in mature forests. All regions see an intensification of agriculture, bringing increased worries about soil degradation. In Latin America and the Caribbean, and Africa, where the intensification is not accompanied by a net reduction in cropland, these concerns are severe.

The privatization of water and improvements in technology lead to increases in water use efficiency in most regions, but the emphasis is primarily on the augmentation of supply. At the same time, the decline in subsidies in most regions affects those less able to pay, be they agricultural, industrial or domestic users. Still, with growing populations, particularly in regions where demand reaches a point of saturation or where climate change results in reduced precipitation, the number of people living in river basins with severe water stress grows significantly. Even though the percentage of wastewater treated grows, the total volume of untreated wastewater continues to increase rapidly.

Terrestrial and marine biodiversity pay a high price. There is a continued decrease in mean species abundance globally, with the largest losses in sub-Saharan Africa, parts of South America, and some areas in Asia and the Pacific. The poor quality of the management of some protected areas, the opening up of others, and the introduction of alien invasives and genetically modified species all contribute to this decline. Although agriculture, through its effect on land use, historically played the dominant role in the reductions in terrestrial biodiversity, its share of changes is eclipsed by climate change and the growth of infrastructure. In fact, except for Africa, and Latin America and the Caribbean, shifts in land-use patterns reduce the pressure that agriculture puts on terrestrial biodiversity. The continued growth in landings from marine fisheries in many regions belies the increasing loss of marine biodiversity.

Policy First

The dominant characteristic of this scenario is the highly centralized approach to balancing strong economic growth with a lessening of the potential environmental and social impacts. A key question is whether the slow and incremental nature of this approach will be adequate.

The first decades of the 21st century see concerted efforts by governments to solve the pressing problems facing the world as it entered the new millennium. Many of these, for example the HIV/AIDS crisis and the lack of access to safe water in many parts of the world, were already evident. Others, such as climate change, make their presence felt, portending much more serious consequences in the future if action is not taken. The pattern of responses to the environmental challenges is characterized by a move towards a more “holistic” approach to governance, particularly in the management of the economy. Economic growth, while seen to be necessary, is no longer pursued without significant consideration of its social and environmental impacts. More specifically, uncontrolled markets are recognized as being limited in their ability to provide many of the public goods-and-services societies hold dear, including the maintenance of key ecosystem services and the stewardship of non-renewable resources. New theories point to the importance of these goods-and-services to longer-term economic sustainability, nationally and internationally. These help to lend support to the increased public investments in, among others, health, education (particularly of women), R&D and environmental protection, even when this requires increased government expenditures. It is also reflected in the richer nations ultimately meeting targets for foreign aid to poorer countries set in the previous century.

National governments and international institutions, including the United Nations and regional organizations, lead in these efforts. In fact, the increasing economic and political integration in the regions is one of the hallmarks of the changes. Previously existing institutions, such as the European Union, expand, while new ones such the Asia Pacific Community for Environment and Development, are formed. For the most part, the private and civil sectors follow and support the efforts of governments.

Although specific actions taken related to environmental governance vary across and within regions, there are common elements, due in large part to the increased coupling of national institutional arrangements to international agreements. “Perverse” subsidies, which encourage the overexploitation of resources, ranging from fossil fuels to water to agricultural land to marine fisheries, are gradually reduced, if not eliminated. Public investments in science and technology grow, and increasingly emphasize environmental concerns, particularly those of the most vulnerable groups. The designation of both terrestrial and marine protected areas increases, and efforts are broadly, albeit not uniformly, effective in terms of preventing land-use change in these areas.

The effects of these choices are seen in many aspects of society and the environment. Climate change and its associated impacts remain a primary concern. A series of international agreements, the removal of subsidies and investments in R&D motivate concerted efforts to increase energy efficiency and move to more low-carbon and renewable sources, including biofuels. Still, total energy consumption continues to increase. Furthermore, in spite of significant growth in renewable sources of energy, oil and gas continue to dominate fuel supplies.

The increased demand for biofuels and food, even in the presence of technological advances and the phasing out of most agricultural subsidies, results in a significant increase in land devoted to pasture, even as land for crops falls slightly after reaching a peak. Much of this increase comes at the expense of forest land.

Strong investments to increase supply and reduce demand, particularly through efficiency improvements, help to alleviate concerns over freshwater availability in much of the world. Still, growing populations and economic activity continue to strain resources, particularly in the developing regions. Globally, the population living under severe water stress continues to rise, with almost all of this increase occurring in those regions exhibiting continued population growth. Social and political institutions, with efforts to better manage shared resources, help to limit the impacts of this stress in most regions.

The increased demand also places a strain on the quality of water resources. While treatment of wastewater expands in all regions, it trails the requirements. The total global volume of untreated wastewater continues to grow, even as the percentage treated increases.

Climate change has a dramatic effect on terrestrial biodiversity. Agriculture is the other significant contributor to these losses. The most severely affected areas are in Central Africa, parts of Latin America and the Caribbean, and parts of Central Asia, because these regions see the greatest changes in land use as biodiversity protection has to compete with food production and the harvesting of biofuels.

The demand for food extends to the world’s oceans, with most parts experiencing an increase in landings. However, in most cases this also involves fishing further down the food chain. The two areas experiencing the most improvement in diversity of the catch – the northwest Atlantic and the south Pacific around Antarctica – do so in part by reducing their landings.

Security First

The dominant characteristic of this scenario is the emphasis on security, which consistently overshadows other values. It is a fairly narrow notion of security, implying increased limits on how people live, both physically and psychologically. Whether people reside behind actual walls or outside, their movements are not nearly as free as might have been imagined looking from the start of the century. Where increased restrictions on migration have reduced the movement of people, the continuation and extension of trade barriers limit the movement of goods across borders. Much of this is driven by continued conflict in many parts of the world, government mandate and lack of resources for many individuals. Thus, at the same time that the world becomes more crowded as population grows, it feels even smaller by many of the choices made by society. A key question is: what might be the broader implications of security first?

Expenditures on security, both public and private, grow at the expense of investments on other priorities, including in R&D in science and technology. Many governments hand over the provision of public services to private interests to improve efficiency and save costs. Both official development assistance (ODA) and foreign direct investment (FDI) contract overall, or become more focused and subject to greater conditionality. International trade follows similar patterns. Internationally, the more unsavoury aspects of the ideas championed by many anti-globalization campaigners in the past prevail. Domestically, broad-based social safety nets either do not develop or deteriorate.

Governments, particularly those that retain strong control at the national level, continue to play a strong role in decision making, but they are increasingly influenced by multinational corporations and other private interests. Very little progress is achieved in reducing corruption in official circles. International institutions, both at the regional and global levels, see their authority decline. Public participation and the role of the civil sector, both domestically and internationally, are increasingly marginalized.

Not surprisingly, environmental governance suffers as a result of these wider changes; where it is “successful,” this is usually to the benefit of particular sectors of society. Most new technologies pay little regard to environmental impacts, and there is a degree of regression in practices, such as the use of inorganic fertilizers. There are various patterns in terms of formal incentives and disincentives related to resource use, but the logic behind these is rarely from an environmental perspective. Globally, there is no expansion of the terrestrial or marine protected area network, and an overall decrease is seen in the level of protection from exploitation of existing protected areas. Also, key environmental services are increasingly the focus of competition and conflict.

The effects of these choices are seen in many aspects of society and the environment. Total energy use increases significantly, reflecting a very slow rate of improvements in energy efficiency. Furthermore, after slow growth in the early decades of the century, there is a dramatic resurgence in the use of coal to the point where it is rapidly approaching the levels of use of natural gas and oil. The net result of these and other forces is a strong rise in the level of atmospheric CO₂, with no sign of a slowing of the rate of increase. The planet continues to warm, with little hint of a slowing down of the rate of increase.

Total SO_x emissions change little. Reductions in Europe, North America and West Asia have been balanced by increases elsewhere. NO_x emissions climb in every region. The health effects of these emissions, particularly in the increasingly crowded urban areas, are felt across the globe.

With the changing climate, the extent of forest in the Arctic increases as species spread north. Europe also sees some increase in its forest area, as does North America, although much of the increase in the latter is not considered mature forest. These patterns are the exception though, as most regions and the world as a whole witness loss of forests, which are converted to food crops and especially to grazing land. Africa, and Latin America and the Caribbean stand out in this regard. The slow growth in income and continued concentration of land ownership in these regions, to a certain extent, slow these trends. The downside to this is seen in the accompanying slow growth in food availability, which is also reflected in continuing high levels of childhood malnutrition in these regions.

The changing climate also combines with growing populations and greater economic activity to further strain freshwater resources around the globe. The slow advances in water use efficiency are not able to prevent dramatic increases in water stress. Globally, there is a dramatic rise in the number of people living in river basins facing severe water stress. The number in Africa alone is nearly as many people as lived in the entire region at the start of the century. Conflicts are witnessed over shared resources, both within and between countries.

Equally concerning is the quality of water. The volume of wastewater produced vastly exceeds the increases in treatment capacity; the net result is a dramatic rise in the amount of untreated wastewater. Again, the poorer regions of the world face the greatest impact, with the increases being significantly higher in places such as West Asia and Africa. The resulting effects in the form of water-borne diseases are significant.

In the absence of concerted efforts, climate change, general population growth, urbanization, and the growth in demand for food and traditional biofuels have significant impacts on terrestrial biodiversity. The expansion of agriculture is eclipsed by increased infrastructure and the changing climate as the primary drivers of biodiversity loss. The loss of species abundance is widespread but certain areas, for example sub-Saharan Africa, parts of Latin America and the Caribbean, and parts of Asia and the Pacific, see greater losses. In addition to these broad patterns of change, some localized areas experience staggering losses as a result of armed conflict.

The pressure on the world’s oceans increases dramatically, particularly in the first few decades of the century. Fish catches increase in most areas, but with a decline in the quality of the catch in most cases. There is some decline in the catch in the later years with the changes in quality varying by area. At the same time, efforts to expand aquaculture and mariculture in many regions increase at the expense of critical ecosystems, including mangrove forests and coral reefs.

Sustainability First

The dominant characteristic of this scenario is the assumption that actors at all levels – local, national, regional and international, and from all sectors, including government, private and civil – actually follow through on the pledges made to date to address environmental and social concerns. This implies behaviour that honours not only the letter, but also the spirit of these promises.

The start of the 21st century sees strong calls on governments at all levels to address the myriad of problems facing the world, reflected by national and international responses such as the Millennium Declaration. At the same time, groups from the private and civil sectors under such rubrics as corporate social responsibility, environmental justice, fair trade, socially responsible investment, and organic and slow food, as well as key individuals with significant personal resources, do not wait for governments to act. They gain momentum and increase influence as their numbers of adherents pass key thresholds.

Reforms take place in both national and international institutions, opening these up to more balanced participation. The rules governing international trade are gradually reformed over time to address broader issues than just economic efficiency. The nature and amount of ODA and FDI evolve to make these more beneficial to all parties. The world witnesses a significant increase in the allocation of public resources to social and environmental concerns, and less towards the military. Underpinning much of this is an underlying but not always explicit compact between the richer and the poorer nations to more seriously address the needs of the latter.

Governments play an important role through actions taken to address social and environmental concerns, particularly in integrating these into all aspects of decision making. The biggest impacts, however, result from their willingness to create the space for, and learn from, actions in the private and civil sectors. The more open and partnership-based approaches result in higher levels of cooperation and compliance, stemming from the increased relevance and legitimacy of government actions. The stage is set for different actors to more easily play their appropriate roles in addressing issues of common concern, drawing on the strengths and minimizing the weaknesses of each.

The evolution of environmental governance reflects both the complementarities and competition between social and environmental goals. In areas such as energy and water provision, efforts are made to balance the desire to reduce overall resource use with the need to address issues such as fuel, poverty and water stress. Increased public and private investments in water infrastructure and energy resources and technologies emphasize meeting these and other challenges in more environmentally friendly ways. Choices have to be made with respect to land use in balancing biodiversity protection and food security, not to mention the increased demand for biofuels. There is an increase in the number of terrestrial and marine areas designated for protection; however, the designations emphasize sustainable use and ecosystem services maintenance, rather than simply species conservation.

The effects of these choices are seen in many aspects of society and the environment. Climate change continues to remain a persistent problem. Through significant efforts, the growth in the level of atmospheric CO₂ is limited, but it will still be a few decades before stabilization is reached. After rising, the rate of change in global temperature falls and continues to decline. Still, it is not possible to avoid potentially significant warming and sea-level rise. At the same time, hope is seen in the transformations in the energy sector. Total energy use increases, but the mix of fuels changes significantly. Oil use peaks, and the use of coal declines to the point that more energy is produced by solar and wind. Both modern biofuels and the latter make up a significant fraction of total energy supply, with natural gas as the overall dominant source of energy.

With respect to more local air pollutants, marked declines are seen in NO_x and SO_x emissions. North America and Europe were already seeing reductions at the start of the century, but all regions follow their lead and at a rapid rate.

With climate change, the extent of forest in the Arctic increases as species spread north. Efforts to address climate change also have an effect on land use, with significant amounts of land devoted to the growth of biofuels. Increased area devoted to food crops in Africa, and Latin America and the Caribbean, even in the light of improved yields, is offset by land taken out of production elsewhere. The expansion of grazing land primarily comes at the expense of forests. The increase in food availability is fundamental in reducing hunger, however. Furthermore, the loss of forest land slows significantly over time.

The widespread adoption of integrated water management strategies with a strong emphasis on demand management and conservation helps to reduce the growth in water stress. Still, in part due to the varying patterns of population growth and shifting patterns of precipitation as part of the changing climate, increases are seen in water stress in some regions, notably Africa, Asia and the Pacific, and West Asia. In almost all regions, though, programmes have been put in place to help people deal with this concern.

The efforts to reduce the growth in water demand also play a role in maintaining and improving water quality around the world. Treatment capacity keeps pace with the increasing amounts of wastewater, such that the total volume of untreated wastewater changes very little. However, the story differs among regions. Some, such as North America almost completely eliminate untreated wastewater while others, such as Latin America and the Caribbean, see small increases in volume even as the percentage treated rises.

Efforts to turn the tide on biodiversity loss are significant, but these face strong challenges due to competing demands for food and fuel, and, most importantly, climate change. The latter becomes, by far, the most important driver of species loss. Parts of Africa, Asia and the Pacific, and Latin America and the Caribbean, also face increased stress due to agricultural expansion, resulting in more significant losses in these areas.

Driven by increased food demand, many parts of the oceans experience increased pressure from fishing, but some experience decreased pressure. Significantly, the mean trophic level of the fish caught stays the same or increases in many parts of the ocean. Designated marine sanctuaries play a key role in these cases. In addition, efforts are made to reduce the potential impacts of aquaculture and mariculture on vulnerable coastal ecosystems.

Implications of the Scenarios

The previous section has provided glimpses of how the future might play out under the assumptions of each of the four scenarios. What are the implications in each case for the environment and human well-being? Following the structure of this report, this section will look in turn at the atmosphere, land, water and biodiversity, and then human well-being and vulnerability. Since they drive many of the results, it begins with a brief look at some overall demographic and economic developments in the different scenarios.

Demographic and economic change

Fig 9.2 Population trends. (Note: IFs modeling results.)

Global population continues to grow in each of the scenarios (see Figure 9.2). It reaches its highest level, around 9.7 billion, by 2050 in Security First. In Sustainability First, there are just under 8 billion people at this time, and very little further growth is expected. Policy First and Markets First see global population reach about 8.6 and 9.2 billion people, respectively. In comparison, the latest UN projections ^[6] are 7.79, 9.19, and 10.76 billion people by 2050 for the low, medium and high variants, respectively. These differences reflect a number of factors, including differences in female education, population policies and income growth in the different scenarios. The largest absolute growth occurs in Asia and the Pacific, but in terms of percentage growth, it is much larger in Africa and West Asia. Europe is the only region that experiences absolute declines during this period, although these are quite small, particularly in Sustainability First.

Fig 9.3 Gross domestic products. (Note: IFs modeling results.)

Global economic activity grows significantly over the scenario period, particularly in Markets First and Policy First, both of which see an approximate fivefold increase in global GDP (see Figure 9.3). Even in Security First, there is nearly a tripling of economic activity. For a comparison, the latest Global Economic Prospects ^[7] describes three scenarios with average annual growth ranging from 2.8–3.7 per cent between 2005 and 2030 (using market exchange rates); the scenarios presented here have growth rates ranging from 2.6–3.9 per cent over the same period (also using market exchange rates). As shown in Figure 9.4, this growth is accompanied by significant increases in global trade, most notably in Markets First. Due in part to their more rapid population growth, the absolute size of the economies in Africa and West Asia grow at about the same rate as the Asia and the Pacific economy in Markets First, Policy First and Sustainability First and somewhat faster in Security First.

Fig 9.4 Total global exports. (Note: IFs modeling results.)

Given its somewhat lower population growth and similar economic growth, Policy First sees faster growth than Markets First in global average GDP per capita, with an increase of nearly 3.5 times over the period of the scenarios (see Figure 9.5). Slightly slower growth occurs in Sustainability First, but global average GDP per capita still more than triples; Security First sees less than a doubling. The most rapid growth occurs in Asia and the Pacific in all scenarios. As with the other currently less well-off regions, somewhat greater growth is seen in Policy First and Sustainability First than Markets First, with Security First having the lowest growth in all regions and the least convergence across regions.

Fig 9.5 GDP per capita. (Note: IFs modeling results.)

Fig 9.6 Global GINI index of income across states and households. (Note: IFs modeling results.)

Fig 9.7 Ratio of GDP per capita – top 10 per cent of population over bottom 10 percent of population. (Note: IFs modeling results.)

Atmosphere

Chapter 2 highlighted the key issues related to the atmosphere. Beginning with energy use, a key pressure, the scenarios illustrate dramatically different possible futures for the atmosphere.

Energy Use

Fig 9.8 Total primary energy use. (Note: IMAGE modeling results.)

Globally, world energy use is expected to increase in all scenarios, driven mostly by increasing energy use in low-income countries (see Figure 9.8). However, per capita energy use in high-income countries remains at a much higher level than in low-income countries (see Figure 9.9). Primary energy use in Policy First and Security First increases from about 400 EJ in 2000 to 600–700 EJ in 2030 and around 800–900 EJ in 2050. This trajectory is consistent with mid-range scenarios in literature^[8]. In relative terms, population growth is a more important factor in growth in Security First, while income growth plays a more important role in Policy First. The trajectory in Markets First lies substantially above the other two scenarios, driven by rapid income growth and more material-intensive lifestyles. In contrast, Sustainability First follows a lower trajectory. Here, a less material-intensive orientation and considerably higher efficiency – partly induced by global climate policy – contributes to the lower energy use.

Fig 9.9 Per capita primary energy use. (Note: IMAGE modeling results.)

Fig 9.10 Global primary energy use by fuel. (Note: IMAGE modeling results.)

In terms of the energy mix, fossil fuels continue to dominate energy supply in all four scenarios (see Figure 9.10). Nevertheless, important differences exist across the scenarios. In Markets First, relaxation of current tensions in international energy markets allow for rapid growth of oil and natural gas use worldwide. In Policy First, moderate climate policies reduce growth of oil demand, bring down coal use, and stimulate the use of bioenergy and zero-carbon options, such as wind, solar and nuclear power. Some of the remaining fossil fuel use in the power sector is combined with carbon capture and storage. In Security First, a totally different picture emerges. Here, growth of oil and natural gas is reduced due to remaining tensions in international energy markets. This is replaced by an increase in coal use. Finally, in Sustainability First a similar picture emerges as in Policy First, but trends are much stronger. Here, as a result of stringent climate policy not only is coal use reduced, but so is oil use. Oil is partly replaced by a strong increase in bioenergy use. While natural gas use increases, its consumption in the power sector is, after 2020, mostly combined with carbon capture and storage.

Emissions of regional air pollutants and greenhouse gases

Fig 9.11 Global anthropogenic SO_x by sector. (Note: IMAGE modeling results.)

At the global level, energy use dominates the anthropogenic emissions of both regional air pollutants, using SO_x emissions as a general indicator, (see Figure 9.11) and GHGs (see Figure 9.12). The relationship between total energy use and emissions is strongly influenced by a variety of other factors, particularly government policies directed at emission controls.

Fig 9.12 Global total equivalent carbon emissions from anthropogenic sources by sector. (Note: IMAGE modeling results.)

The total emissions of regional air pollutants decline in all scenarios other than Security First. This is a clear consequence of the lack of emissions controls in that scenario. The dramatic declines in Policy First and Sustainability First reflect a combination of strong policy efforts to reduce emissions per unit energy use as well as relatively slower overall growth in energy use and moves towards cleaner fuels. Markets First exhibits an overall decline, but the overall increase in economic activity keeps it from matching the reductions in Policy First and Sustainability First.

Fig 9.13 Per capita equivalent carbon emissions from energy and industry by region. (Note: IMAGE modeling results.)

The largest increase in GHG emissions over the scenario horizon, more than a doubling, occurs under Markets First, reflecting its increase in energy use and the lack of effective mitigation policies, highlighted by a lack of progress in reducing per capita emissions (see Figure 9.13). For similar reasons, Security First also shows a large increase, although this is somewhat smaller, because of more moderate economic growth. In comparison, emissions under Policy First and Sustainability First peak and subsequently decline during the scenario period. This is mainly driven by the implementation of policies to reduce GHG emissions. In the early years, however, Policy First actually has the highest emission of all scenarios due to higher levels of emissions from land-use changes. These emission levels are all within the range of projections considered in the latest IPCC reports ^[9]. (For further detail on comparing the climate related projections in the scenarios with those presented in the IPCC, see Box 9.1)

Atmospheric CO₂ concentration and global mean surface temperature

Fig 9.14 Atmospheric concentration of CO₂. (Note: IMAGE modeling results.)

The trend in global CO₂ concentration reflects the trends in emissions and the uptake of atmospheric CO₂ by the ocean and biosphere. The highest CO₂ concentration is reached in Markets First, exceeding 550 ppm in 2050 (see Figure 9.14). Policy First and Security First result in about the same concentration, around 540 ppm in 2050, despite having distinctly different pathways over the period. In case of Security First, the increases in CO₂ Policy First actually has the highest increases in CO₂ concentration at the start of the scenario period, but the rate of increase slows significantly by the end of the period. Sustainability First results in the lowest concentration by a significant margin, about 475ppm in 2050, and is also the only scenario where the concentration has approached stabilization. concentration are lower in the beginning of the scenario period because of the lower emissions, but they continue to increase at an accelerating rate.

Fig 9.15 Global mean temperature deviation trends since industrial times. (Note: IMAGE modeling results.)

All scenarios show a distinct increase of the global mean temperature, ranging from about 1.7°C above pre-industrial levels in 2050 in Sustainability First to about 2.2°C in Markets First, with Policy First and Security First reaching about 2.0°C (see Figure 9.15). These represent the actual changes in temperature in 2050; due to inertia in the climate system, additional warming would be expected in all of the scenarios irrespective of emissions that might occur after 2050.

Sea-level rise

Fig 9.16 Sea-level rise due to climate change. (Note: IMAGE modeling results.)

The processes governing sea-level rise as a result of climate change, for example thermal expansion of oceans and melting of ice, have long response times. Hence, sea-level responds slowly to the changes in temperature. The computed sea-level rise in all of the scenarios is about 30 centimetres in 2050 relative to the pre-industrial era, with only the smallest of differences between them (see Figure 9.16). This magnitude of sea-level rise implies increasing risk of coastal flooding during storm surge events, accelerating beach erosion, another changes to the world’s coastal zones. As with the global mean surface temperatures, the sea level continues to rise far beyond the time horizon of these scenarios, which is indicated by the steady rate of increase observed at the end of the scenario period.

Land

One of the major environmental challenges is the conservation of land to maintain its ability to supply ecosystem goods-and-services (see Chapter 3). The growth of population, economic wealth and consumption leads to an increase in the overall pressure on land use in each scenario, as well as increased competition between different uses.

Land for agriculture, biofuels and forests

Fig 9.17 Cropland and pasture by region. (Note: IMAGE modeling results.)

Fig 9.18 Modern biofuel plantations as percentage of total land cover by region. (Note: IMAGE modeling results.)

Fig 9.19 Forest land by region. (Note: IMAGE modeling results.)

In all scenarios, the use of land for traditional agricultural purposes – food crops and pasture and fodder – increases the most in regions where arable land is still available, notably Africa, and Latin America and the Caribbean (see Figure 9.17). These shifts also imply differences among regions in terms of the reliance on land expansion versus aggressive improvements in yields for agricultural growth. In Security First, agricultural land expansion is the smallest, since low economic growth keeps the increase of human demands for land within limits. Markets First and Sustainability First show comparable results but for different reasons. In Markets First, the growth in demand for land is partially compensated by technological developments, whereas in Sustainability First, such improvements are counterbalanced by greater concern for food availability. In Policy First, the total area is highest, due to the similar concerns and higher population levels than in Sustainability First. In Policy First and Sustainability First, which include strong targets for the mitigation of GHGs, there is an added demand on land for the production of biofuel crops (see Figure 9.18). The effect of these demands for agriculture and biofuels is reflected in the changes in forest land (see Figure 9.19). Latin America and the Caribbean, and Africa see significant declines in forest land in all scenarios, most notably in Policy First, where nearly all of Africa’s forests are lost. Meanwhile, Europe and North America see small increases, particularly in Markets First.

Land degradation

Fig 9.20 Global extent of soils with high water erosion risk. (Note: IMAGE modeling results.)

The continuation of food production from agricultural land is threatened in different ways. First, rainfall erosion increases, due to increases in precipitation because of climate change. Precipitation increase is strongest under Markets First, although the differences among scenarios are still small in 2050, because of the inertia in the climate system. Water erosion is greatest in agricultural areas, independent of the soil and climatic conditions.

Combining trends in climate and land-use change and the erodibility index allows a calculation of the water erosion risk index. Compared with the present situation, the area with a high water erosion risk increases by almost 50 per cent in all scenarios (see Figure 9.20). Differences among the scenarios up to 2050 are relatively small. The risks under Sustainability First and Markets First are somewhat less than under the other scenarios, although there is a period during which they rise in the former as more biofuel crops are introduced. The increases are largest under Policy First, mainly due to larger food demand, combined with an increased demand for biofuel crops.

Desertification

Another threat to crop production is desertification. It has been identified as a major social, economic and environmental problem for many countries around the world. Just like land degradation, desertification results from natural factors (such as change in precipitation) and human causes (such as land clearance and excessive land use) or a combination of both.

Changes in arid areas (as a result of climate change) are relatively small. This follows from the fact that climate change results in increasing precipitation, but also increasing evaporation (as a result of temperature increase). For desertification, however, the increase in arid areas is less important than the pressure on these areas. Therefore, the combination of agricultural land expansion in arid areas leads to an increased vulnerability to climatic shocks.

Yields and food availability

Fig 9.21 Cereal yield by region. (Note: IMAGE modeling results.)

The changes in land use and quality, as well as advances in technology and general economic developments, such as trade, are reflected in the changes in agricultural yields and food availability. All regions experience increasing cereal yields per unit area in all scenarios, but these are significantly lower in Security First, reflecting slower developments in technology and poorer land management practices (see Figure 9.21). The increasing demands for food, along with greater investments in technology, result in the largest increases in Markets First and Policy First, with some differences among regions. Sustainability First shows slightly lower growth, but this is counterbalanced by a lower overall population.

Fig 9.22 Per capita food availability. (Note: IMAGE modeling results.)

Figure 9.22 highlights the projected changes in per capita food availability. Overall food production increases in all four scenarios, but per capita food availability is also influenced by the different rates in the growth of the population. Significant increases are seen in Markets First, Policy First and Sustainability First, with the latter achieving global levels 10 per cent and 5 per cent higher than the first two, respectively. In Security First, food production barely keeps up with population growth after 2020, and the beginnings of a decline are seen around 2040, with that in Africa happening much sooner. By 2050, there is more than a 30 per cent difference in per capita food availability between Security First and Sustainability First globally, and a 70 per cent difference in Africa.

Water

As discussed in Chapter 4, water – both its quantity and quality – is fundamental to the environment and human well-being. The scenarios show that very different futures for water are plausible depending on our choices in the near future.

Water use

Fig 9.23 Global water withdraws by sector. (Note: WaterGAP modeling results.)

One of the consequences of the rapid push for better material standard of living in Markets First is a rapid growth in water use in all socio-economic sectors, resulting in a large increase in withdrawals from surface and groundwaters (see Figure 9.23). Trends differ greatly from country to country; in many industrialized countries water use reaches a saturation point during the scenario period, whereas the growing incomes in developing countries lead to an increasing demand for modern water services. In Markets First, the privatization of water services and improvements in technology lead to a moderate but steady increase in the efficiency of water use in most regions. Nevertheless, the water sector emphasizes the expansion of water supply rather than water conservation. Under Policy First, a change in water-use behaviour in households and industries, together with rapid improvements in the efficiency of water use in all sectors, leads to a decrease in water withdrawals in many industrialized countries, and a slower growth elsewhere. Under Security First, a growing population and neglect of water conservation tends to push water withdrawals upwards. Yet, slower economic growth tends to slow the increase. Sustainability First assumes widespread adoption of integrated water management strategies, with strong emphasis on demand management and conservation. These developments, together with slower population growth rates, lead to slower increases in overall water use.

Persons living in areas with severe water stress

The extent of severe water stress will be complicated by the effect of climate change on the future water supply in all scenarios. Increasing precipitation will increase the annual availability of water in most river basins, but warmer temperatures and decreasing precipitation will decrease annual water availability in some arid regions, such as West Asia, southern parts of Europe, and northeastern parts of Latin America and the Caribbean. Changes in climate could also lead to more frequent periods of high and low run-off (not shown). By 2050, the occurrence of droughts could become more common in already arid areas, such as Australia, southern India and Southern Africa. Meanwhile, increasing precipitation could cause more frequent high run-off events in parts of Asia and the Pacific, Latin America and the Caribbean, and North America.

Fig 9.24 Populations living in river basins facing severe water stress. (Note: WaterGAP modeling results.)

These factors combine with the increases in demand and population growth to determine the number of people living in river basins with severe water stress (see Box 9.2 and Figure 9.24). In Markets First, the affected population grows from around 2.5 billion people in 2000 to nearly 4.3 billion people in 2050. In Policy First, actions to slow the growth in water use help alleviate concerns about freshwater availability in much of the world. Nevertheless, growing populations and economic activity continue to put a strain on resources in some places, particularly in the developing regions. The global population living under severe water stress rises by 40 per cent to nearly 3.9 billion people. The net effect of high population and increased demand in Security First is that the population living in river basins under severe water stress in 2050 exceeds 5.1 billion people. The number living with water scarce conditions in Africa approaches 800 million, nearly as many people as lived in that region at the start of the century. The developments under Sustainability First with respect to water use, together with slower population growth rates, lead to significant reductions in water stress in many river basins. Still, in part due to the varying patterns of population growth and shifting patterns of precipitation as part of the changing climate, there are increases in some regions, notably Africa, Asia and the Pacific, and West Asia. The number of people living in river basins with severe water stress increases by more than 1.1 billion globally. In both Sustainability First and Policy First, it is expected that many actions will be taken to help people in river basins facing stress to better cope with water scarcity. These include programmes to reduce water wastage in the distribution of water and highly efficient programmes to manage surface- and groundwater.

Wastewater treatment

Fig 9.25 Untreated domestic and municipal wastewater by region. (Note: WaterGAP modeling results.)

A consequence of the rapid increase in water withdrawals in Markets First is a similarly rapid growth in the production of wastewater. Although treatment plant capacity expands, it cannot keep up with the increase in volume of wastewater. Hence, the total worldwide volume of untreated wastewater from the domestic and manufacturing sectors doubles between 2000 and 2050 (see Figure 9.25). Since most of this wastewater is discharged into inland surface waters, the world experiences a serious spread of water pollution problems and health risks. In Policy First, the level of wastewater treatment increases from around 50 to about 80 per cent between 2000 and 2050, but because of growing population, the total volume of untreated wastewater still increases by about 25 per cent during this time (see Figure 9.25). Yet, the global average hides significant disparities among regions. While the total volume of untreated wastewater shrinks by more than half in Europe, it nearly doubles in LAC. Since the coverage of communities with wastewater treatment plants is also relatively low under Security First, the volume of untreated wastewater increases by more than a factor of three between 2000 and 2050. The discharge of these large volumes of untreated wastewater to surface waters causes widespread water contamination, worsening health risks and degrading aquatic ecosystems. Under Sustainability First, efforts to reduce the growth in water demand also contribute to maintaining and improving water quality around the world. Treatment capacity manages to keep pace with the increasing amounts of wastewater, such that the total volume of untreated wastewater has changed very little since the turn of the century (see Figure 9.25). This, however, masks large differences among regions. In North America, the volume of wastewater is drastically reduced, while in Latin America and the Caribbean the volume increases by a small amount.

Biodiversity

Across the scenarios and regions, global biodiversity continues to be threatened, with strong implications for ecosystem services and human well-being as described in Chapter 5. This is the case for both terrestrial and marine biodiversity. However, there are clear differences among the scenarios in the magnitude and location of change.

Terrestrial biodiversity

Fig 9.26 Mean species abundance and trends, 2000 and 2050.

All regions continue to experience declines in terrestrial biodiversity in each of the scenarios. Figure 9.26 shows the levels of Mean Species Abundance as of 2000 and the changes in each of the scenarios from 2000 to 2050; Figures 9.27–9.28 summarize these changes by region and contribution. The greatest losses are seen in Markets First, followed by Security First, Policy First and Sustainability First for most regions. Africa, and Latin America and the Caribbean experience the greatest losses of terrestrial biodiversity by 2050 in all four scenarios, followed by Asia and the Pacific. The differences among the regions are largely a result of the broad-scale land-use changes already described, especially increases in pastureland and areas dedicated to biofuel production. The overall changes in terrestrial biodiversity though, are influenced by a number of other factors, including infrastructure development, pollution and climate change, as well as public policy and conflict.

Agriculture, including crop and livestock production, has greater overall biodiversity impacts in Policy First and Sustainability First than in the other scenarios, both because food security is highly valued in these worlds, and because there is a greater uptake of biofuels based on agricultural products. Tropical forests continue to be particularly vulnerable to conversion.

Fig 9.27 Change in mean original species abundance (MSA) from 2000 by region. (Note: GLOBIO modeling results.)

On a global scale, much more biodiversity loss is seen in Markets First than in any other scenario, with infrastructure development playing a major role. In Markets First, global population growth is more limited, and road construction and urban development are more regulated than in Security First. However, the drivers of development are stronger in Markets First: international markets for goods are strengthened, infrastructure is developed to promote access to natural resources, and wealth creation is valued more highly than conservation. In Markets First and Security First, the biodiversity loss continues to accelerate as the scenario progresses, but within Policy First and Sustainability First, the global rate of loss stabilizes by 2050.

Fig 9.28 Contribution to historical decline in mean original species abundance (MSA) to 2000 and to 2050-Global. (Note: GLOBIO modeling results.)

The impacts of climate change are modelled as being similar in each scenario, but in reality, these will be moderated by the ability of species and ecosystems to adapt and migrate. Resilient, well-connected ecosystems suffer fewer ill effects from climate change than fragmented, overexploited ecosystems, such as those seen in Security First and Markets First. The rate at which the global temperature continues to rise has a profound influence on the survival chances of many of the worlds’ species until 2050 and beyond.

Under Policy First and Sustainability First, the protected area network is expanded to create ecologically representative national and regional systems of protected areas. A minor expansion is seen in Markets First, and virtually none in Security First; the investment dedicated to and effectiveness of protected area management within the different scenarios follows the same pattern. While the new protected areas do not limit the overall amount of wildland converted to agricultural use, they protect some of the most critical remaining habitat, including that inhabited by endangered species with restricted ranges. This effect is