http://www.thedailygreen.com/environmental-news/latest/thunderstorms-climate-change-0713

More intense thunderstorms combined with damaging winds are expected to occur because of climate change, according to speakers at the seventh European Conference on Severe Storms being held in Helsinki, Finland.

But because thunderstorms are small in size on the scale of existing climate models it is not possible to tell whether they will also lead to more tornadoes and larger size hail - two of the most damaging problems associated with severe storms.

In a warmer world, increases in surface temperature and moisture create conditions for thunderstorms becoming more intense - and more frequent, researchers say.

Climate change also decreases the temperature difference between the poles and the equator. It is this temperature difference - when cold and warm air masses collide - that causes dangerous wind sheer, in turn producing the devastating tornadoes such as occurred recently in Oklahoma.

Due to the limitations of global models, scientists have so far been unable to say whether the risk of tornadoes increases as a result of these twin effects. Harold Brooks, a researcher into severe thunderstorms at the National Severe Storms Laboratory in the United States, is optimistic.

"According to latest research, the intensity of tornadoes will not increase, therefore incidents like in Oklahoma are not expected to be more frequent than today," Brooks said.

"However, most of the research on severe thunderstorms and tornadoes in climate change has focused on the United States and it is unclear how well the lessons learned there apply to the rest of the world."

While tornadoes are less of a problem outside the United States, heavy hail frequently causes severe crop losses and property damage in Central and Eastern Europe, across Bangladesh, India and other large land masses. Lightning and large hail also kills people caught out in storms.