Snowstorms don’t mean climate change threat has passed: expert
British Columbia’s holiday snowstorms drove everybody crazy. But, apparently, no one more so than climate scientists.
“Every time there is a freaking snowfall, it seems like everybody is going, ”˜What’s going on?’” Andrew Weaver told the Straight. “It’s frustrating as a climate scientist.”
Weaver, a climate-modelling expert at the University of Victoria and a lead author with the Intergovernmental Panel on Climate Change, explained that whenever a cold streak hits, some people question accepted theories of climate change and grow skeptical about global warming. But a few days of snow does not mean that the Earth is not getting warmer.
“People mix up weather and climate,” Weaver said in a telephone interview from Victoria. He described weather as what is here and now, like the sun shining or rain falling. Climate, on the other hand, is more long-term.
Weaver explained climate change as a “shift in the distribution of the likelihood of the occurrence of weather events towards the warm”. He continued, “What that means is it doesn’t mean that it will never be cold; it means that the likelihood of it being cold diminishes with time, and the likelihood of it being extremely warm increases with time.”
A probable reason for 2008’s cold snap is La Nina, according to Weaver. He explained that El Nino is a warm phase of atmospheric interaction and La Nina is the opposite—a cold phase.
“So there is overall warming, but it is not happening in a straight line; it oscillates as we go up,” Weaver said.
Because weather patterns in 2008 were partly shaped by a relatively strong La Nina, it was often cooler than the last few years.
Perhaps it is surprising then that early data indicates that 2008 is on track to be one of the 10 warmest years on record, according to the U.S. National Oceanic and Atmospheric Administration.
Furthermore, a December 16, 2008, NOAA media release states that the global land surface temperature for 2008 was the fifth warmest on record, 0.80 degrees Celsius above the 20th century mean of 9.0 degrees Celsius.
Weaver complained that too often, people’s definition of normal is only based on what happened the previous summer. “It hasn’t been a cold year,” he said, “It’s just that it has [been cold] relative to last year. 2007 was the warmest year on record for land temperatures alone. So it’s a little colder this year.”
Weaver, author of Keeping Our Cool: Canada in a Warming World (Viking Canada, $34), noted that for decades, climate scientists have consistently said that with climate change, many parts of the world should expect an increase in overall precipitation. “So the fact that we’re getting snowfall records is entirely consistent with what we’ve been saying,” he said.
Climate change due to human activity is largely caused by the release of CO2 emissions, which trap the sun’s energy within the Earth’s atmosphere.
The Intergovernmental Panel on Climate Change’s 2007 report states that atmospheric concentrations of carbon dioxide reached 379 parts per million in 2005, greatly exceeding the natural range for the last 650,000 years.
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