Two studies, which have appeared in the journal Nature, have directly linked rising greenhouse gas levels to rising intensity of rain and snow in the Northern Hemisphere, and to the increased risk of flooding in the UK.
While there is a high degree of certainly that human activity is causing climate change, its implications for regional weather have not been clear. Localized weather extremes have been more difficult to link to climate change with any degree of reasonable certainty.
Gabriele Hegerl, a climate researcher from the University of Edinburgh, UK, is quoted as saying, “Climate models have improved a lot since ten years ago, when we basically couldn’t say anything about rainfall,” until now.
The researchers compared data from weather stations in the Northern Hemisphere with precipitation simulations from eight computer climate models. Hegel said,
“We can now say with some confidence that the increased rainfall intensity in the latter half of the twentieth century cannot be explained by our estimates of internal climate variability,”
It was found that extreme rains and floods had increased by 7 per cent in the second half of last century across the northern hemisphere.
The other study has linked climate change to a specific event, the damaging floods in England and Wales in 2000. The researchers ran thousands of seasonal forecast simulations with and without the effects of greenhouse gases. They found that climate change may have almost doubled the risk of extremely wet weather that caused the floods.
The implication from these studies is that Northern Hemisphere countries will need to be prepared for more of these severe weather events in the future.
Researchers have also pointed out that climate change may not always raise the risk of weather related damage. For instance, snow-melt floods may become less likely as the climate warms. The study also leaves a 10 percent chance that climate change has not affected the UK’s flood risk.
Nature reports that similar studies are underway for flood and drought risk in Europe, meltwater risk in the western US, and drought in southern Africa.
It has also been pointed out that more research is needed in order to conclusively lay blame on climate change for more extreme weather events.
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