New El Niño Likely to Have Major Impacts

A new ‘El Niño’ is intensifying, and whilst it may have lead forecasters to a perhaps premature prediction of a ‘barbecue summer’, it is likely to have major impacts on global weather systems over the coming year. Forecasters say this El Niño could be the second-strongest on record.

El Niño is a periodic warming of the normally cold waters of the eastern tropical Pacific. It occurs every two to seven years, and is defined as occurring when ocean surface temperatures in the region rise by more than 0.5C above average. Since the Pacific is a heat reservoir which drives wind patterns around the world, this change can dramatically affect global weather systems. The last El Niño was in 2006-07 and, at its peak, sea surface temperatures averaged about 0.9 degrees above normal. This time, sea surface temperatures are already +0.5 to +1.5C above average across much of the equatorial Pacific Ocean.

The very strong El Niño of 1997-98 made 1998 the world’s hottest year on record, and caused major droughts and catastrophic forest fires in South-east Asia which sent a pall of smoke right across the region. At present, forecasters do not expect this El Niño to equal that of 1998, but it may be the second-strongest, leading to increased drought in Africa, India and Australia, heavier rainfall in South America and increased extremes in Britain. 2010 could again be one of the hottest years on record, and the ecological impacts could be significant. Given the effect that short-term weather patterns have on public attitudes about climate change, it will be interesting to see if there is an uptick in public concern around the time of the Copenhagen Climate Change Conference in December.

For further details, please see The Independent.