Snow looks pretty. But climate change and the storms it triggers are dangerous

פורסם: 2 בפבר׳ 2015, 5:56 על ידי: Sustainability Org   [ עודכן 2 בפבר׳ 2015, 6:09 ]
Sarah Laskow, 27/1/2015
‘Global warming’ doesn’t stop when winter comes – and dramatic cold weather events are exactly what scientists predict will be the result.
unimpressive times square snow
  It’s not just the ball that was dropping in Times Square this January. Photograph: Mike Segar/Reuters

It isn’t news to anyone that global temperatures are rising. Last month was the warmest December the world has seen in 135 years. Last year was the warmest year on record: according to the National Oceanic and Atmospheric Administration, the average combined temperature of land and ocean surfaces was 1.24°F about the 20th century average.

Yet, as you may have noticed or read, it’s been snowing on the east coast of the United States – a lot. And that too is the result of what we call “global warming”.

It seems to be counterintuitive. Aren’t we worried about melting ice? Yes. Isn’t snowpack diminishing high in the mountains, where it matters most? Yes. But it is also true that in some places in the world – and the northern United States is one of them – dramatic winter snowstorms are exactly what scientists expect from climate change.

Snow, after all, counts as precipitation. And the International Panel on Climate Change says that it’s “very likely” that, as the world warms up, “extreme precipitation events will become more intense and frequent” in North America. Warmer global temperatures mean more moisture gets sucked into the atmosphere, and at some point, that moisture comes down – come rain or come snow, you might say.

Climate scientists don’t like to attribute any one nasty storm to climate change. (It is possible, but it’s a huge task to crunch all the necessary data and only a handful of studies have tried.) But they do know that winter storms in the northeast US have indeed been increasing in frequency and intensity. As Mashable’s Andrew Freedman points out, five of New York City’s top 10 snowfalls happened in the past 15 years. Record snowstorms can occur during warm years, too, one study found: while the researchers documented an increase in extreme regional snowstorms over five decades, they noted that about a third of those storms happened during years that were warmer than average.

Snow days used to be welcome fun. But because winters are getting warmer, average snowfall over a whole season is often down. And whatever snow does fall often melts more quickly than it did in the past. So, even after a massive snow fall, we don’t get much time to enjoy its pleasures – digging out igloos once the storm has passed, pretending we’re Laura Ingalls Wilder and trying to make maple candy in the snow, sledding down that one big hill.

Big snowstorms instead just leave long-lasting scars. That’s particularly true on the east coast, where flooding and storm surges can threaten beaches – the heart and soul of the American summer. Living inland, you might not normally associate a snowstorm with a flooded basement. But that’s what people who are close to the water need to be prepared for during a storm like this one, when the winds whip up waves taller than 10 feet and tides surge higher than normal. On Monday, the National Weather Service was predicting “severe beach erosion” in particular for Massachusetts, which just released a report on coastal erosion inspired by damage inflicted by winter storms in 2013. Shorelines are already prone to erosion during winter months, but this storm could wash away enough sand to cause new inlets to break through barrier beaches. This is akin to the coastal damage other parts of the Northeast saw during Hurricane Sandy in 2012 – high winds and water are a bad combination, no matter what time of year they happen.

This will happen even as on mountaintops snow is melting earlier, ponds are no longer freezing over for the winter, and the world is getting warmer. We call this “climate change” now, instead of global warming, because the phenomenon is so full of contradictions. A warmer average temperature doesn’t mean that snow will disappear instantly; a warm winter can still have a record snow storm and beaches are in danger in the winter, too.

The reality of climate change is that it doesn’t stop just because winter comes. Warming up the world is tipping all of its weather systems out of whack, and it seems like every year some new record is broken. So starting 2015 with a record-breaking snowstorm won’t necessarily keep it from also being one of the hottest years on record. That’s just the kind of can’t-win contradiction that we’ve created by messing with the environment of a perfectly good planet.