I'm not dreaming of a white Christmas, because the upcoming snow will bring yet another year of alleged geniuses declaring that climate change isn't happening because there's a blizzard outside. The phenomenon of pro-Big Oil, anti-Al Gore conservatives claiming climate change is a hoax because there's snow on the ground has provoked in me a response I call climate-denial denial: I can't bring myself to admit that some of these people, people I used to respect, can really be this ignorant.
When one doesn't know about something, it always helps to ask somebody who actually knows about something. So let's consult people who actually know a bit about science to explain why snow does not disprove climate change:
· "On a global scale, the most recent decade (2000-2009) has been declared the warmest decade on record since the 1880s, when temperatures were first recorded. But the recent snow storms have led to considerable confusion about how record snow relates to our changing climate. Snowfall is a combination of the moisture in the atmosphere and air temperature. As the Earth's temperature warms, the oceans evaporate more water to the atmosphere which produces more precipitation -- notably more extreme precipitation -- including heavy snowfall when conditions are below freezing." (Union of Concerned Scientists News Center, February 1, 2011)
· "Most don't see a contradiction between a warming world and lots of snow. That includes Kevin Trenberth, a prominent climate scientist at the National Center for Atmospheric Research in Colorado. 'The fact that the oceans are warmer now than they were, say, 30 years ago means there's about on average 4 percent more water vapor lurking around over the oceans than there was, say, in the 1970s,' he says. Warmer water means more water vapor rises up into the air, and what goes up must come down. 'So one of the consequences of a warming ocean near a coastline like the East Coast and Washington, D.C., for instance, is that you can get dumped on with more snow partly as a consequence of global warming,' he says. And Trenberth notes that you don't need very cold temperatures to get big snow. In fact, when the mercury drops too low, it may be too cold to snow." ("Get This: Warming Planet Can Mean More Snow," NPR.org, February 15, 2010)
· "The 2009/2010 winter saw a number of dramatic, record breaking snowstorms. Early February saw two 'once in a 100 years' snowstorms hit Philadelphia, now being dubbed 'Snowmageddon.' Does record snowfall prove that global warming isn't happening? What do observations say? 2009 was the second hottest year on record. January 2010 was the hottest January in the UAH satellite record. Satellites data indicates last month was the second hottest February in the satellite record. Observations tell us that rumours of global warming's death have been greatly exaggerated...If global warming is still happening, why are some areas experiencing record snowfall events? As climate warms, evaporation from the ocean increases. This results in more water vapour in the air. Globally, atmospheric water vapour has increased by about 5% over the 20th century. Most of the increase has occurred since 1970 (IPCC AR4 22.214.171.124). This is confirmed by satellites that find the total atmospheric moisture content has been increasing since measurements began in 1988 (Santer 2007). The extra moisture in the air is expected to produce more precipitation... To claim that record snowfall is inconsistent with a warming world betrays a lack of understanding of the link between global warming and extreme precipitation. Global temperatures in the last few months of record snowfall are some of the hottest on record. Warming causes more moisture in the air which leads to more extreme precipitation events. This includes more heavy snowstorms in regions where snowfall conditions are favourable. Far from contradicting global warming, record snowfall is predicted by climate models and consistent with our expectation of more extreme precipitation events." (John Cook, "Does record snowfall disprove global warming?" SkepticalScience.com, March 7, 2010)
· "Rising temperature is only one effect of climate change. Probably more crucially, warmer air holds more water vapor than cold air does. The increased evaporation from land and sea leads to more drought but also to more precipitation, since what goes up eventually comes down. The numbers aren't trivial--global warming has added 4 percent more moisture to the atmosphere since 1970. That means that the number of 'extreme events' such as downpours and floods has grown steadily; the most intense storms have increased by 20 percent across the United States in the past century. So here's the thing: Despite global warming, it still gets cold enough to snow in the middle of winter...As Jeff Masters, the widely read weather blogger, pointed out last week, a record snowstorm requires a record amount of moisture in the air. 'It is quite possible that the dice have been loaded in favor of more intense Nor'easters for the U.S. Mid-Atlantic and Northeast, thanks to the higher levels of moisture present in the air due to warmer global temperatures,' he wrote." (Bill McKibben, "Washington's snowstorms, brought to you by global warming," Washington Post, February 14, 2010)
The next time you hear a cable-news pundit or op-ed columnist poke fun at climate science after a major snowstorm, ask yourself if these folks are even capable of walking and chewing bubble gum at the same time. Then turn the channel, stop reading the column, and ask yourself if ignorance will destroy us before climate change does.
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