Record-breaking “meteorological misery” from coast to coast is making it clear that severe weather may well be the new normal. Weather is getting more extreme and this, scientists tell us, has a lot to do with climate change. Meanwhile, inside the Beltway and among mainstream media, there’s virtually no public debate about the likelihood we’re already paying the high price of climate change
To be sure, we can’t definitively pin any single weather event to climate change. Weather is about near-term changes in the atmosphere; climate is about long-term changes to the atmosphere over time and the larger interrelations of ocean, ice and land. As Nasa puts it, “When we talk about climate change, we talk about changes in long-term averages of daily weather.” As such, weather is like climate’s rambunctious little brother who’s always in your face.
For decades, climate scientists have been writing an increasingly precise script for climate change and now nature has snatched the lead role with abandon. One recent report from the US Climate Change Science Programme, “Weather and Climate Extremes in a Changing Climate” (pdf), summarised weather extremes this way:
“With continued global warming, heat waves and heavy downpours are very likely to further increase in frequency and intensity. Substantial areas of North America are likely to have more frequent droughts of greater severity. Hurricane wind speeds, rainfall intensity, and storm surge levels are likely to increase. The strongest cold season storms are likely to become more frequent, with stronger winds and more extreme wave heights.”
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Here in Canada the situation is very similar and “Merchants of Doubt” driven by extreme political ideology, religious fanaticism or corrupt vested business interests continue to divert policy making away from necessary mitigation and adaptation strategies. The mainstream media also cling to “balanced reporting” effectively encouraging doubt mongers, contrarians and denialists to express unsubstantiated opinion in contrast to legitimate and robust scientific evidence.
I recommend highly that you download and read the report from the US Climate Change Science Programme, “Weather and Climate Extremes in a Changing Climate” (pdf) (Synthesis and Assessment Product 3.3 Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research)
Citation: CCSP, 2008: Weather and Climate Extremes in a Changing Climate. Regions of Focus: North America, Hawaii, Caribbean, and U.S. Pacific Islands. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. [Thomas R. Karl, Gerald A. Meehl, Christopher D. Miller, Susan J. Hassol, Anne M. Waple, and William L. Murray (eds.)]. Department of Commerce, NOAA’s National Climatic Data Center, Washington, D.C., USA, 164 pp.
Changes in extreme weather and climate events have significant impacts and are among the most serious challenges to society in coping with a changing climate.
Many extremes and their associated impacts are now changing. For example, in recent decades most of North America has been experiencing more unusually hot days and nights, fewer unusually cold days and nights, and fewer frost days. Heavy downpours have become more frequent and intense. Droughts are becoming more severe in some regions, though there are no clear trends for North America as a whole. The power and frequency of Atlantic hurricanes have increased substantially in recent decades, though North American mainland land-falling hurricanes do not appear to have increased over the past century. Outside the tropics, storm tracks are shifting northward and the strongest storms are becoming even stronger.
It is well established through formal attribution studies that the global warming of the past 50 years is due primarily to human-induced increases in heat-trapping gases. Such studies have only recently been used to determine the causes of some changes in extremes at the scale of a continent. Certain aspects of observed increases in temperature extremes have been linked to human influences. The increase in heavy precipitation events is associated with an increase in water vapor, and the latter has been attributed to human-induced warming. No formal attribution studies for changes in drought severity in North America have been attempted. There is evidence suggesting a human contribution to recent changes in hurricane activity as well as in storms outside the tropics, though a confident assessment will require further study.
In the future, with continued global warming, heat waves and heavy downpours are very likely to further increase in frequency and intensity. Substantial areas of North America are likely to have more frequent droughts of greater severity. Hurricane wind speeds, rainfall intensity, and storm surge levels are likely to increase. The strongest cold season storms are likely to become more frequent, with stronger winds and more extreme wave heights.
Current and future impacts resulting from these changes depend not only on the changes in extremes, but also on responses by human and natural systems.