Extreme weather and climate change connections

Thomas Karl :  How climate change will be felt by you and impact your neighbors is probably going to be through extreme weather and climate events.

Thomas Karl is director of the U.S National Climatic Data Center, the world’s largest active archive of weather data. Karl was a lead author of a 2008 report that found an increase in extreme weather and climate events happening now in the United States.

Thomas Karl:   Extreme events are a manifestation of climate change, and probably one of the more significant aspects of global climate change.

For example, said Dr. Karl, as average temperatures across North America rise, what was once a rare, extreme heat wave becomes more common.

Thomas Karl :  We’ve got data going back, in some instances, to the early part of the 20th century. This index looks at extremes of temperature – hot extremes, cold extremes – extremes of precipitation –  wet extremes and drought.  It looks at one-day very local heavy precipitation events, like flash floods.  And it looks at the number of consecutive dry days,  a stretch of very dry weather, short-term droughts.  It looks at hurricanes, in terms of their frequency and intensity. If we take a look at all those factors and integrate them together, we see a very clear signal of an increase in the number of extremes.

Karl said extreme weather events may sneak up on us…

Thomas Karl : We may be fine for many years, and all of a sudden, one particular season, one particular year, the extremes are far worse than we’ve ever seen before.  Unless we’re prepared to adapt, or begin to try and mitigate the amount of greenhouse gases into the atmosphere, we’re likely to be put into a situation we won’t be looking forward to.