2.2.2 Acidification

a key concern in developing countries is the potential impact of acidification on agricultural crops

Acidification, the process by which soils and surface waters are depleted of bases and consequently suffer an increase in acidity, results in damage to terrestrial and aquatic ecosystems. Thousands of lakes and small streams have become acidified during this century in Europe and North America, and the flora and fauna in these lakes have changed drastically. Many surface waters are entirely devoid of fish, amphibians and other creatures. There has also been significant damage to forests in Europe and North America.

Emissions of sulphur dioxide, nitrogen oxides and ammonia give rise to acidifying depositions after chemical transformation and transport in the atmosphere. Sulphur and nitrogen oxides are mainly formed during the combustion of fossil fuels in the power and transport sectors. This is the energy-acidification nexus.

Recognition of this linkage has led to a Sulphur Protocol under the Convention on Long-Range Transboundary Air Pollution in Europe requiring significant reductions of sulphur emissions. However, even if the requirements of the protocol were fulfilled, large areas will have acid depositions well above critical levels.

The prognosis indicates that there is potential for serious damage in many parts of the world that have not experienced this type of pollution problem before. Technologies exist to abate these emissions, but they are costly and need to be put in place on a widespread scale.

In many developing countries emissions are increasing to serious levels. A key concern in these countries is the potential impact on agricultural crops. Whereas in industrialised countries farmers can lime the soils if they become acidified, it is unlikely that poor farmers in the developing world can afford to do so. Acidic deposition is likely to become an important regional issue, particularly in Asia, but also in parts of South and Central America and in Southern Africa.