Environment: Is it El Nino, or just another cold winter?

The weather phenomenon known as El Nino, which caused a devastating drought in South-east Asia and floods in east Africa, is also disrupting the climate of Europe, according to scientists at an environment conference in Japan. Richard Lloyd Parry in Kyoto assesses the evidence.

New research suggests that summer floods in Germany, and even this week's snow in Britain, have both been influenced by the El Nino effect which is likely to generate a wet, relatively warm winter in England, especially in the South-west.

The phenomenon is the subject of much discussion at the United Nations conference on climate change being held in Kyoto. The aim of the gathering, attended by delegates from more than 160 countries, is to reach a global agreement on quotas for the reduction of greenhouse gases, which are believed to cause global warming.

Despite circumstantial evidence, there is no scientific consensus yet on whether the gases, principally carbon dioxide, have exacerbated El Nino. But the research offers striking examples of the effect seemingly small variations in temperature can have on the weather of places thousands of miles apart, an alarming foreshadowing of the potential effects of global warming.

The climatological "event" known as El Nino is a periodic rise in the temperature of the eastern Pacific, around Peru and the Galapagos Islands. There was a strong El Nino in 1982 and 1983, and a lesser version of the phenomenon was observed throughout the late 1990s. This summer, however, saw the most powerful El Nino on record, resulting in heavy rain in the eastern Pacific, and unusual dryness in southern Africa and Central and South America.

In South-east Asia, there was a severe drought causing serious food shortages in New Guinea and contributing to forest fires in Indonesia which enveloped the whole region in a choking smog. A subsequent warming of the Indian Ocean has led to devastating floods in Somalia and southern Ethiopia. But far from being confined to the tropics, El Nino has also had pronounced effects in Europe, according to unpublished work circulating among scientists at the Kyoto conference.

Scientists at the European Centre for Medium Range Weather Forecasting in Reading have produced computer models which attempt to iron out random weather variations to isolate the specific effects of El Nino. Compared to North America, Asia and Oceania, the impact of the phenomenon on Europe has in the past been considered mild. But the strength of this year's event has made it easier to distinguish between the genuine El Nino "signal" and the run-of-the-mill fluctuations in weather known to meteorologists as "background noise".

Projections for previous months have been shown by subsequent weather to be accurate; for December, January and February, the computer model suggests that El Nino will contribute to unusually warm, wet weather in the southern part of Britain, especially in Cornwall.

The remarkable range of the effects of El Nino have long been known, but until now scientists have been uncertain about its effects on Europe. According to Dr Anver Ghazi, head of the European Commission's Climate and Natural Hazards Unit, which is funding the research, the effects of El Nino appear also to have contributed to the rain which caused devastating floods in central Europe this summer.