More of everything?

More of everything?

• Parts of Europe and Asia including China will see more acidification in their environment in the coming years.
•Agricultural land will expand from approximately 37 per cent of the total land area presently to around 50 per cent by 2050. The highest increases are projected to take place in Africa and West Asia.
•The total global water demand will grow substantially from 3,000 km 3 in 1990 to 4,300 km 3 in 2050.
•Life expectancy is expected to reach a global average of just over 70 years by 2050 compared with 75 years or more today in developed countries.
•The future years could foresee a population that is on average wealthier and in better health, but living in a world with scarcer resources.
•With the world economy increasing maybe five-fold and the need to reduce environmental pressures by at least by a factor of two for many problems, the efficiency of resource use should be increased ten-fold globally in the coming half-century.

these are the shocking results of a recent draft of a model-based study of the state of global environment. The world environment has undergone a major change ever since industrialisation began to feature as an important cornerstone of national economic policies. In their quest to become rich, countries turned a blind eye towards the environment. It was only in the past few decades that a green sense enveloped nations and an ecological perspective began to surface as a serious global concern. The Rio summit in 1992 resulted in the formation of Agenda 21, the global action plan for promoting sustainable development.

In response to Agenda 21, the un Environment Programme (unep) initiated a new biennial reporting series called the Global Environmental Outlook (geo). The geos are aimed at supporting the implementation of Agenda 21 by monitoring its progress, assessing the state of the environment, identifying emerging issues and giving support to priority issues for international action. As a contribution to the first geo report, rivm or the Dutch National Institute of Public Health and Environment, one of unep's collaborating centres has made a model-based assessment of future global environment according to a 'Conventional Development' (cd) scenario (see box: As is where is), developed by the Stockholm Environment Institute (sei). This scenario with a time frame up to ad 2050, is based on an extension of historical developments and trends, assuming no major social, political, technical or natural surprises or disruptions. On the basis of the modelling tools available, the assessment of the future state of the global environment focused on two important areas of interaction between socio-economic developments and the environment, namely, (a) global and regional cycles of carbon and sulphur emissions and (b) the use of land and water resources.

The geo assessments project a not-so-green future for the world. Major findings indicate that environmental pressures will build up accompanied by a change in climate; acidification will become a serious problem in some developing regions; freshwater scarcity will aggravate; and, with agricultural land expanding, the natural habitat for preserving biodiversity will shrink. Acid rain: first-degree burns on nature
The problem of acidification arises when two key conditions are met: first, a region has a high level of economic activity with intensive use of fossil fuels leading to large atmospheric emissions of acidifying pollutants. These emissions must be large enough to be transported through the atmosphere for long distances in significant quantities. The second condition is that soil, forest and aquatic ecosystems in a region are susceptible to these acidifying pollutants. Recent assessments have identified the northern and central parts of Europe, the eastern part of China and the southern parts of Asia as regions at the greatest risk of damage as a result of acidification. In the case of Asia, even with the partial controls assumed in the cd scenario, the critical loads for sulphur deposition are still expected to be exceeded substantially. Consequently, woodlands in some of these developing areas could deteriorate more rapidly, endangering agricultural production and the supplies of fuelwood and other products. The acid deposition can lead to the release of toxic metals to ground and surface water, further contaminating drinking water supplies. Clearly, if there are no controls the negative effects of acidification in Asia would be much worse.

A change for the worse
Up to now, most impact assessments of climate change have centred on industrialised countries at medium and high latitudes. This is partly because computer models predict that the largest temperature changes are likely to occur at these latitudes, but also since most research focuses on those regions where more research funds are available. Nevertheless, models also indicate that developing countries in low latitudes may experience important changes in climate, including crucial rainfall patterns.

Acidification and climate change have the same root cause, namely a high level of economic activity that results in emissions of huge amounts of polluting substances into the atmosphere. Many of these pollutants stem from the same source - burning of fossil fuels. In 1990, this accounted for over 80 per cent of the global emissions of carbon dioxide and about 94 per cent of the European emissions of sulphur dioxide (so₂) the main cause for acidification of Europe's environment. The two environmental issues are not only related with respect to their causes, but also with respect to their impacts. Recently, a better understanding has emerged as to how these two problems interact. The emissions of acidifying pollutants, especially so₂, lead to accumulation of particles in the upper atmosphere which partly mask the global warming caused by greenhouse gases (ghgs). If the level of particles in the atmosphere is assumed to remain constant at their 1990 marks, the growth in ghgs would increase the global average surface temperature by about 1.5 c from 1990 to 2050 (see graph: A hotter world). If however, global emissions of so₂ increase proportionately with the use of fossil fuels in developing countries, then the mass of particles in the atmosphere will also increase and will moderate this warming trend. The consequence of this is that if the emissions of acidifying gases were reduced, decreasing aerosol concentrations would 'unveil' the warming caused by the increase in ghg concentrations.

Food harvest
Today, the world produces enough food to feed all people sufficiently. However, in many parts of the world malnutrition is widely prevalent due to insufficient access to food because of poverty, social upheaval or war. Global human food consumption figures show that while the daily average world per capita caloric intake of 2,700 kilocalories (kcal) is substantially above the critical level (1,900 kcal/capita), there is a major difference in caloric intake between developing (2,470 kcal/capita) and the industrialised regions (3,490 kcal/capita).

In the cd scenario, per capita food intake continues to grow in most developing regions (from 2,470 kcal/capita) to 2,930 kcal/capita by 2050), while it stabilises in the industrialised regions. Global food supply increases in the scenario faster than population because of the assumed shift in diets towards luxury food products, especially the consumption of animal products. The total agricultural commodity supply for 2025 and 2050 is given for the world as well as for both developing and developed regions (see table: How much we need).

According to calculations, agricultural land will expand from approximately 37 per cent of the total land area presently (of which one-third is arable land) to 46 per cent by 2015 and to around 50 per cent by 2050. The largest increases are projected to take place in Africa and West Asia (about 50 per cent by 2015 and 90 per cent by 2050 compared to 1990). This increase of cultivated land in these areas results from a very sharp rise in demand; in particular, the assumed continuation and expansion of traditional animal husbandry and farming systems requires a lot of additional grazing land.

Parched terra firma
Of the huge freshwater resources available on earth only a small amount is technically and economically accessible to humans. Presently, agriculture accounts for about 70 per cent of global freshwater withdrawals, industrial use for about 22 per cent and domestic water consumption for the rest. According to the cd scenario, total global water demand will grow substantially from 3,000 km 3 in 1990 to 4,300 km 3 in 2050 (see graph: Draining the earth). Compared to developed nations, the developing regions account for most of the growth in freshwater withdrawals. This is mainly due to population growth as per capita use of water is assumed to actually decrease due to more water efficient systems.

A healthier world
Over the last four decades, there has been an enormous and continuing improvement in health worldwide, although there are poignant regional exceptions. In the past, developed regions have shown a health transition, formed by both demographic as well as epidemiological transitions. In developing regions, life expectancy has increased substantially over the last few decades. This has led to a sharp increase in population, despite declining birth rates in many countries.

In the cd scenario, it is assumed that health transition will continue to unfold in future in interaction with socio-economic developments. Life expectancy is expected to reach a global average of just over 70 years by 2050 compared with 75 years or more today in developed countries. This discrepancy is due mainly to remaining large differences in income levels.

Taking stock: assessing the results
It appears that cd may well lead to a future with a population that is on the average wealthier and in better health, but living in a world with scarcer and more degraded natural resources. A selection of input assumptions in the cd scenario and findings of the model-based assessment (out put) is given in the graph Higher we go. The cd scenario results in economic, social and environmental achievements. However, these are at risk if the assumed socio-economic developments are not realised, while a range of environmental and social problems are expected to persist in any case. Clearly, the cd scenario does not lead to sustainable development as many sustainability goals, as stated in Agenda 21, would not be reached.

The geo assessment leaves out issues like depletion of minerals, non-terrestrial stocks (fish) and more local environmental problems like waste, air pollution, toxification, poor drinking water quality. Likewise, the modelling tools available do not yet enable a quantitative feedback of results from the assessment of the food and freshwater availability into the assessment of the future state of health. Notwithstanding the limitations, we believe the what if assessment already offers useful insights putting forth global and regional policy priorities and effective strategies for sustainable development. As for policy options to overcome the tide, here are a few suggestions:

• The interlinkages between different environmental problems have to be taken into consideration. Our analysis, for example, demonstrates how issues of food security, climate change and biodiversity are closely connected, for instance, through land use and land cover implications. Therefore, integrated policies have to be designed in addition to policies that address only one issue at a time. This implies a balanced attention to economic, social and environment issues so the interconnectedness of the various complex socio-economic and environmental issues is recognised.

• It is crucial to take into account regional differences and priorities as our analysis clearly shows that the environmental impacts of socio-economic developments are very different across regions. In the industrialised temperate and boreal zones in the northern hemisphere the mitigation of environmental pressures through the excessive use of materials and energy deserve high priority. Anticipatory action is also required as largescale environmental changes can lead to (adverse) impacts with considerable delay.

• Finally, for decreasing environmental pressure under conditions of rapid growth of population and production and consumption, rapid but sustainable increases in the intensity of resource use are essential components of any sustainable development policy portfolio. The cd scenario assumes that total environmental pressure (emissions, land conversions) continues to build up. It has been suggested that, with a world economy increasing maybe five-fold and the need to reduce environmental pressures by at least by a factor of two for many problems, the efficiency of resource use generally should be increased ten-fold globally in the coming half-century. This can be achieved not only by technological developments, but also by dematerialisation of lifestyles.

The article is an edited version of a paper prepared by the authors The authors are responsible for methodology, scenario and policy options at the Dutch National Institute of Public Health and Environment (RIVM), Bilthoven, The Netherlands