Cold weather poses special challenges to climate communicators. It’s laughably easy for climate contrarians to point to cold and snow in an attempt to dismiss climate science. Admittedly, when I put on snowboarding pants and a ski mask to bike to a job where I talk and write about global warming all day, I find a little bit of humor in it, too.
The good news is it’s easy to debunk these arguments and put the focus back on what scientists really know. Cold weather and snow also provide some important lessons about staying credible when it comes to extreme weather.
Coming in From the Cold
First, we need to put cold weather in context. If there were no climate change, we’d expect to see just as many record highs as record lows. But as the Earth has warmed, we now have twice as many record highs as record lows in the United States.
So climate change, at least in the near term, is not the end of cold weather. And while it might be cold today, winter is getting milder and spring is arriving, on average, 10 days sooner. That’s expanding wildfire season and disrupting many animal species that live on tight, annual clocks.
Cold also has concrete benefits, especially for apple, blueberry and maple syrup farmers, whose crops depend on a base number of chill days to thrive. Cold snaps also kill insect larvae and keep insect populations in check. In the West, milder winters are helping lead to larger beetle populations that are decimating forests.
And if you’re from Wisconsin, New England or other areas where pond hockey and cross-country skiing are childhood hallmarks, it’s important to note the squeeze warmer weather will have on winter recreation.
Extreme snowfall is an ephemeral beast and climate communicators should tread carefully with it. Many of us remember the 2010 blizzard that blanketed the Northeast and shut down Washington, DC. I helped two friends move during the storm, so my memories are perhaps slightly more visceral. I also remember Senator James Inhofe having some fun with his family by erecting an igloo on the Mall and sticking an “Al Gore’s Home” sign on it.
Misleading and mean? Sure. That’s politics for you. But it was effective communication, too.
In the wake of “Snowmageddon,” we convened six leading snow and climate researchers to ask them what they thought scientists could fairly say about snowfall and climate change.
Like most scientists, they said they first wanted to emphasize the bigger picture: Climate change is altering the character of our seasons, as noted above.
The snowfall story, they said, can be complicated. Snow can only form when temperatures are below 32 degrees and when there is enough water vapor in the air. While climate change makes it less likely that any given day will fall below the 32 degree threshold, it also causes the air to hold more moisture.
Due to increasing temperatures, scientists see a shift away from snow and toward rain. When they look at the overall picture for precipitation – including rain and snow – there has been a measurable concentration of precipitation in the heaviest events.
They also see that snow cover, which measures the extent and length to which snow stays on the ground, is shrinking. At the same time, the United States’ historic “Snow Belt” is shifting, and the region that receives heavy snow is moving northward.
Snow pack – which refers to the snow that builds up in mountain regions – is also declining. This is especially troubling for the U.S. Southwest, where mountain snow is a vital water source. When that snow melts rapidly, water managers struggle to deliver it to homes, businesses and farms.
At the same time, the researchers told us, more moisture in the air can lead to heavier snowfall, but only when other conditions are favorable. Therefore, it isn’t clear that climate change can be linked to heavy snowfalls in a straightforward way.
For climate communicators, it’s much better to lead with what scientists definitely know – and the consequences those findings will have for us – than to get into more speculative findings about heavy snowfall and climate change. And it’s always worth pointing out that a heavy snowfall does not negate the multiple lines of evidence pointing to global warming, including evidence of warmer conditions in winter.
Going to Extremes and Staying Credible
It’s tempting to point to every instance of extreme weather and say, “See, that’s climate change for you.” But scientists’ confidence in climate change’s link to various sorts of extremes varies. When it comes to tornadoes, for instance, scientists don’t have a long, consistent record from which they can work. By contrast, increasing intensity and frequency for heat waves is well documented in more than 100 years of temperature data. Scientists have also been making strides with “attribution studies” that can help them determine how much impact human-induced climate change had on specific weather events.