Scientists help explain extreme weather

Edinburgh scientists have contributed to a study that sheds light on the causes of extreme weather.

Researchers from the UK and the US investigated 12 extreme weather events, such as Hurricane Sandy.

They found that man-made climate change played a part in half of the events.

Weather factors

Some 18 research teams from around the world contributed to the study, which examined extreme events on five continents and in the Arctic.

Scientists say the research will help them better understand the complexities of natural and human factors that contribute to extreme weather and climate events.

In addition, understanding the range of influences on extreme events helps scientists to better understand why extremes are changing.

Heatwaves and storms

Among their findings, the report says spring and summer heatwaves in the United States can be mainly explained by natural atmospheric dynamics.

However, man-made climate change was a significant factor, contributing approximately 35 per cent to the extreme warmth between March and May.

They say storms with a similar impact to Sandy are likely to occur more frequently, with the same damage produced by storms of less severity, as sea levels continue to rise from both natural and human-induced factors.

Researchers also found that very low Arctic sea ice extent in summer 2012 is extremely unlikely to have occurred because of solely natural climate variability.

The study will be published in a supplement to the Bulletin of the American Meteorological Society.

We found no evidence that the recent wet summers in Scotland and North-West Europe were caused by changes in Arctic sea ice; they are likely a natural event though it is possible that human influences had some role.

Professor Simon TettSchool of GeoSciences