First and foremost, let’s get something out of the way: weather and climate are not the same thing. Climate is a long-standing pattern of temperature, precipitation and other atmospheric conditions in a given area, while weather looks at those same parameters over a much shorter time span. Wait 10 minutes, and the weather might change. Climate change, on the other hand happens over a much longer period of time, which means that it usually takes many years to notice any kind of shift in climate.
In a report published by the American Meteorological Society, researchers took a look at all the extreme weather events of last year, and attempted to see which were linked to climate change and which were just flukes of nature.
In all, 32 groups of scientists from around the world looked into 28 different extreme weather events, from drought and heat waves to storms, snowfall and flooding.
Among their findings, they found that heat waves in Asia and Australia were more likely due to climate change. Extreme rainfall in an area of Southern France was three times more likely than in the year 1950, because of climate change. A heat wave in Argentina during December 2013 was five times more likely to occur with the influence of climate change. Drought in East Africa? Floods in Indonesia? Cyclones hitting Hawaii? Also linked to climate change for 2014.
But not every bad storm or dry spell can be traced back to human-caused climate change. There were a huge number of winter storms in North America and a huge number of storms over the United Kingdom during the winter of 2013-2014, but those events could not be linked to climate change. Nor could the drought in northeastern Asia.
And some events happened in spite of global warming. In 2014, Antarctic sea ice reached a record-setting high. The culprit? Winds that blew cold air from the Antarctic continent out over the sea, speeding the freezing process. The authors caution that this event, already an anomaly is likely to become even rarer as temperatures continue to rise.
The report is now in its fourth year.
“For each of the past four years, this report has demonstrated that individual events, like temperature extremes, have often been shown to be linked to additional atmospheric greenhouse gases caused by human activities, while other extremes, such as those that are precipitation related, are less likely to be convincingly linked to human activities,” Thomas R. Karl, director of NOAA’s National Centers for Environmental Information said in a statement. “As the science of event attribution continues to advance, so too will our ability to detect and distinguish the effects of long-term climate change and natural variability on individual extreme events. Until this is fully realized, communities would be well-served to look beyond the range of past extreme events to guide future resiliency efforts.”
Previous years reports are also available online.