'Warming could unleash more violent storms'

Global warming could unleash more violent thunderstorms, flash floods and forest fires in the coming years, according to an Israeli researcher.

The Tel Aviv University (TAU) researcher has predicted that for every one degree Celsius of warming, there will be approximately a 10 per cent increase in lightning activity.

This could have negative consequences in the form of flash floods, wild fires, or damage to power lines and other infrastructure, says Colin Price, TAU professor and head of geophysics, atmospheric and planetary Sciences.

Under an ongoing project on the impact of climate change on lightning and thunderstorm patterns, he and his colleagues have run computer climate models and studied real life examples of climate change, such as the El Nino cycle in Indonesia and Southeast Asia, to determine how changing weather conditions impact storms, the Journal of Geophysical Research and Atmospheric Research reports.

An increase in lightning activity will have particular impact in areas that become warmer and drier as global warming progresses, including the Mediterranean and the southern United States, according to the 2007 United Nations report on climate change, a TAU statement said.

When running their state-of-the-art computer models, Price and fellow researchers assess climate conditions in a variety of real environments. First, the models are run with current atmospheric conditions to see how accurately they are able to depict the frequency and severity of thunderstorms and lightning in today’s environment.

Then, the researchers input changes to the model atmosphere, including the amount of carbon dioxide in the atmosphere (a major cause of global warming) to see how storms are impacted.

Price compared their results with vastly differing real world climates, such as dry Africa and the wet Amazon, and regions where climate change occurs naturally, such as Indonesia and Southeast Asia, where El Nino causes the air to become warmer and drier.

“During El Nino years, which occur in the Pacific Ocean or Basin, Southeast Asia gets warmer and drier. There are fewer thunderstorms, but we found 50 per cent more lightning activity,” says Mr. Price.

Typically, he says, we would expect drier conditions to produce less lightning. However, researchers also found that while there were fewer thunderstorms, the ones that did occur were more intense.

These findings have been presented at the International Conference on Lightning Protection.