By Ania Lichtarowicz of BBC Science (Sunday, 9 January, 2000)

Climate change events could soon be much easier to predict thanks to a newly compiled set of climate data. Scientists from the American space agency Nasa have put together the first global set of rainfall figures for each month in the last 20 years. Meteorologists hope it will lead to a better understanding of climate change and help predict when extreme phenomena might occur.

El Nino and La Nina are complementary climate events. El Nino occurs every few years and causes warming of the Pacific Ocean near South America, while La Nina keeps the water cool and is considered to be the normal climatic condition. Global rainfall

When it occurs, El Nino can have severe and often detrimental effects on rainfall around the world.

These changes in rainfall may lead to food scarcities for animals or cause deadly diseases like meningitis to spread to new parts of the globe.

Nasa scientists have now compiled data from a number of different satellites, as well as space missions and rain gauge information, to give an analysis of global rainfall each month over a period of 20 years.

They hope that by creating more accurate computer models of global atmospheric changes they will be able to understand better certain climate events and predict where the amount of rainfall will change.