Future choices.

We are at a crossroads with the future in our hands. The decisions taken today and tomorrow will define the kind of environment this and future generations will enjoy. GEO-3 outlines four policy approaches leading to different outcomes over the next 30 years. It highlights two of the most contrasting scenarios: Markets First and Sustainability First. One envisions a future driven by market forces, the other by far-reaching changes in values and lifestyles, firm policies and cooperation between all sectors of society.

* Land. By 2032, nearly 3 per cent of the Earth's surface has been built on under a "Markets First" future. The extent of cities and other built-up areas, at over 5 per cent, is highest in Asia and the Pacific region under this scenario. It is lowest in Europe, at around 2 per cent. There are also big rises in Africa and West Asia. While the actual percentage may appear small, the increase in roads, power lines, airports and other infrastructure developments has much wider impacts on wildlife.

Under a "Sustainability First" scenario, the area of built-up land continues to rise but falls slightly in North America and Europe, below 2 per cent, as policies lead to more compact cities and better planning.

* Freshwater. The number of people living in areas with severe water stress both in absolute and relative terms increases in virtually all parts of the globe under the Markets First scenario. An estimated 55 per cent of the global population is affected, up from over 40 per cent in 2002. The highest proportions are in West Asia, with over 95 per cent, and in Asia and the Pacific, with over 65 per cent.

Under a Sustainability First future, most regions see the area under water stress remaining more or less constant or even falling as more efficient management of water reduces water withdrawals, especially for irrigation. In West Asia, the number living in areas of severe water stress is kept at around 90 per cent of the population. In the United States, the figure halves to around a fifth of the population and in Europe, it drops from around a third to just over 10 per cent by 2032.

* Forests and biodiversity. The rapid expansion of infrastructure foreseen in the Markets First future is likely to lead to ever-increasing destruction, fragmentation and disturbance of...