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Get ready for more extreme weather.
Reuters reports that Australia's Bureau of Meteorology says the climate models it monitors indicate a possible
return of the El Niño weather pattern in the second half of 2012. That means one thing: more heavy rainfall and more droughts. If what we saw 14 years ago is any guide, it’s going to be disastrous.
The last El Niño was in 1998 and that was a complete disaster. According National Geographic, it bore more energy than a million Hiroshima bombs. By the time it had run its course eight months later, the giant El Niño of 1997-98 had completely transformed weather patterns around the world, killing an estimated 2100 people, and causing at least $US33 billion ($A32.6 billion) in property damage.
The El Niño is totally transformative. It changes air pressure patterns and trade winds stop moving west across the Pacific. Without those winds, things get hotter and hotter until it hits a threshold for what meteorologists call “deep convection”. That’s the point at which the steamy surface air blasts into the upper atmosphere. When that happens, water in the upper atmosphere condenses and falls as torrential rain.
Scientists estimate that in the past 98 years, there have been 23 El Niños and 15 La Niñas. Of the century’s ten most powerful El Niños, the four strongest have occurred since 1980. Does climate change have anything to do with it? Some scientists are convinced it does.
”El Niño moves heat,” Tom Karl, one of NOAA’s veteran climate experts told National Geographic, “both in terms of water temperature and in atmospheric convection. This heat is transported out of the oceans and the tropics during the peak of El Niño as global temperatures increase. As the heat is released, the whole El Niño cycle begins again, with less cloudiness in the tropics and with the oceans absorbing more heat. With global warming there is more heat available. So the cycle may be shortened because the recharge time is shorter or because the release of heat is less efficient.”
According to the UK based Climate & Development Knowledge Network losses from weather-related disasters are doubling globally every 12 years. Its study found that 2011 was the costliest year on record for disasters, with estimated global losses of $U380 billion. The most expensive events included the Japan earthquake and tsunami, floods in Thailand which affected industrial areas. Extreme weather in the United States also had an impact. Average global economic disaster losses have risen by 200 per cent over the last 25 years adjusted for inflation, the study says.
That could be a taste of what’s ahead with El Niño. It will get worse.
As reported here, in Australia, strong El Niños can slash wheat crop output, threaten water supplies by cutting river flows, shrink city reservoirs and dry out forests, and trigger bush fires. Major El Niños occurred in 1982-82 and 1997-98. We had a weak El Niño in 2002-2003. That led to severe drought in Australia.
The only positive from the 1998 disaster is that climate scientists are now more prepared than ever before. At least we’ll be ready for it.