At this week’s annual meeting of the American Association for the Advancement of Science
(AAAS) researchers served notice that episodes of extreme weather like Superstorm Sandy
and the extended severe drought in Texas are the new normal as human-driven climate change makes such events more intense and more frequent.
Just a few days after President Obama made reference to Superstorm Sandy and other wild weather events in his State of the Union address
, researchers meeting at the AAAS, while echoing the President’s remarks that single events don’t constitute a trend, pointed to a number of factors highlighting why we seem to be experiencing ever more severe meteorological conditions:
• In the 1950s, the number of days setting record high temperatures in the U.S. equalled the number of days setting record low temperatures. Fifty years on, record highs were twice as likely as record lows.
• Precipitation falling as the heaviest rain and snow events in the U.S. increased almost 20% since the 1950s.
• Since the 1970s, almost every measure of hurricane activity in the Atlantic Ocean, from frequency to storm intensity, has increased substantially.
Donald Wuebbles, an atmospheric scientist from the University of Illinois, commented,
“The scientific analyses are now indicating a strong link between changing trends in severe weather events and the changing climate. Every weather event that happens nowadays takes place in the context of a changed background climate.”
“Globally the temperatures are higher, the sea levels are higher, and there is more water vapor in the atmosphere, which energizes storms. So nothing is entirely natural anymore. The background atmosphere has changed and continues to change due to human activity.”
“While a particular heat wave may have still have occurred in the absence of human-induced warming, it would not have been as hot, or lasted this long, and such events would not occur as frequently.”
A body of evidence has gradually been built up by ecologists and wildlife biologists which points to climate change affecting when and where plants flower and animals breed but biologist Camille Parmesan of the University of Texas at Austin said some of these botanical and zoological changes can be brought about by incidents of extreme weather, with even just a few days of extreme heat or rainfall having an impact.
Whilst acknowledging that factors such as pollution and shrinking habitats can combine with climate change and affect the plant and animal kingdoms, Parmesan said studies of coral reefs and other natural habitats suggest that “if we reduce these other human stresses, we actually can increase resilience and resistance in natural ecological systems.”
The researchers made no forecasts as to the ability of humans to survive in the face of more extreme weather but they did highlight some historical events pointing to societies that had failed to adapt to changes in climate.
David Stahle, a tree-ring scholar from the University of Arkansas spoke on tree-ring analysis from the American Southwest suggesting a drought in the 13th century. So severe was the drought that it may have forced the inhabitants of Mesa Verde, Colorado to abandon their fields and homes. He commented,
“The historical record shows us a community that may have failed environmentally. We are doing the same thing now in terms of our heavy consumption of water and fossil fuels.”
Donald Wuebbles made reference to farmers in the American Midwest already engaged in altering planting times and even crop types as a result of severe drought and floods seen in recent years.
This year’s extreme drought in Texas has been monitored by Texas State climatologist John Nielsen-Gammon. He said the extreme conditions in Texas had more to do with extreme high temperatures rather than lack of rainfall. In Texas, reservoirs are at their lowest levels in almost a quarter of a century. In spring 2013, the Texas state legislature will discuss a water plan intended to guarantee supplies for the next 50 years. The difficulty, as Nielsen-Gammon pointed out, is the required outlay
“... it costs $53 billion, and there’s presently no mechanism to fund it. Up until this point, climate change has been largely an abstract concept because some of the United States has not seen a large increase in temperatures until just recently. The awareness of the importance of dealing with climate change is just now becoming apparent within our state.”