Life's a gas...

The global warming crisis ...and a new enemy

If one issue has dominated the environmental debate during the last decade it is global warming.

Most reliable sources now agree that failure to control the emission of greenhouses gases like carbon dioxide (CO2) will contribute to a temperature rise of 1.0-3.5 degrees Celsius by the year 2100.

The grave consequences of this rise are well known to many. They include a rise in sea levels, which will displace millions of people in low-lying delta areas and on island states, reduced agricultural production in the tropics and sub-tropics, where there is already widespread food deficiency, unpredictability in the supply of fresh water, the reintroduction of serious diseases like malaria to Europe and the wholesale loss of important ecosystems and biodiversity.

Disastrous consequences
In addition to these developments, there is little doubt that climatic change is a major contributory factor in making natural disasters nightly television news. The rising incidence and increased severity of windstorms, fires and floods seems to have its roots in disrupted weather patterns.

The UN estimates that three million people perished as a result of natural disasters in the last three decades. According to the Munich Reinsurance Company, global economic losses during 1997 and 1998 reached $120,000 million - eight times higher than the 1960s.

As a result of the UN-sponsored Kyoto Protocol, efforts are under way to slow down CO2 emissions - though there is little sign that these are sufficiently far-reaching to have any major impact on the problem. In 1996, CO2 emissions hit a record high of 23,900 million tonnes.

GEO-2000 concludes that meeting Kyoto targets "is a formidable challenge for some countries but only a first step in bringing under control what is generally agreed to be the most critical environmental issue the world faces. Even if all the targets agreed at Kyoto were met, this would have an insignificant effect on the stabilization levels of carbon dioxide in the atmosphere."

The New Nitrogen Threat
While the issues surrounding CO2 and global warming have been well-publicised, nitrogen has also emerged as a major concern for the coming century. If CO2 is the price paid for rapid industrial development, then nitrogen loading in the environment is the direct consequence of intensive agriculture and the cultivation of leguminous crops.

Human activities have doubled the amount of nitrogen available for uptake by plants (Vitousek and others 1997). Unfortunately, half of all nitrogen applied to plants in the form of fertilisers is lost to the air or dissolved in water. We are fertilising the Earth on a global scale and in a largely uncontrolled experiment.

While fertiliser consumption is stable in industrialised countries, it is on the increase in developing nations. The rising demand for food from an ever expanding global population makes it likely that fertiliser use will increase further in the coming century.

Controlling nitrogen emissions is critical for a number of reasons. For example, increased nitrogen levels in water supplies has meant the introduction of costly purification systems in countries like the US. Nitrogen-based gases are also a key contributor to air pollution.

Excess nitrogen levels also trigger unwanted plant growth in estuaries and coastal areas. A massive increase in algal blooms is leading to underwater oxygen starvation which, in turn, is responsible for significant fish kills in areas like the Black Sea, Baltic Sea and Chesapeake Bay.

Furthermore, nitrogen emissions already account for 6% of the enhanced greenhouse effect and current trends suggest this problem will get worse.

GEO-2000 observes that there is "growing consensus among researchers that the scale of disruption to the nitrogen cycle may have global implications comparable to those caused by disruption of the carbon cycle."

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