Climate change and extreme weather. Some say they are linked, others are not so sure. One extreme weather event seems to be definitely linked, and that is extreme heat waves.
A new, peer-reviewed report, “Explaining Extreme Events of 2013 From a Climate Perspective,” looked at 16 extreme weather events across four continents in 2013. 22 separate studies are included in the report from groups of scientists across the world.
This report points to a relationship between extreme heat waves and our role in climate change. It becomes a bit murkier when looking at other extreme weather events.
One example that was pointed out was the five days of heavy rain that impacted the area around Boulder, Colorado last September. The extreme rains killed ten people and caused more than $2 billion in damage. Climate change, right? The warmer atmosphere across the globe holds more water, and leads to more rain. Not so fast.
While the atmosphere on average is warmer across the world, it’s not in northeastern Colorado, according to a portion of the BAMS report by Martin Hoerling of NOAA’s Boulder lab. Hoerling and his colleagues used a climate model to look at rains during the preindustrial climate compared to today’s. No increase in extreme rain events were found. In fact, a similar heavy rain event impacted the area in the same month back in 1938.
Let’s go back to the heat waves. Nine studies looked at five heat waves that impacted parts of the world in 2013. Specifically, in Europe, China, Korea, Japan and Australia. Scientists found that in all five cases, “human-caused climate change – primarily through the burning of fossil fuels – was found to have clearly increased the severity and likelihood of those events.”
In Australia’s case, the heat waves and accompanying droughts were “virtually impossible without the influence of human-caused global warming.”
Prof David Karoly, a researcher with the University of Melbourne, said, “This research across four different papers goes well beyond that. If we were climate detectives then Australia’s hottest year on record in 2013 wasn’t just a smudged fingerprint at the scene of the crime, it was a clear and unequivocal handprint showing the impact of human caused global warming.”
Dr. Sarah Perkins, a researcher with the University of New South Wales, added, “If we continue to put carbon into our atmosphere at the currently accelerating rate, years like 2013 will quickly be considered normal and the impacts of future extremes will be well beyond anything modern society has experienced.”
Today’s report tells us the link between climate change and heat waves is clear. But, natural variability affects other extreme weather events including heavy rains. One thing is for sure, more studies will be conducted on various weather events as they happen.
Image: Location and type of weather event studied.