How to talk about global warming when it's freezing and snowing outside

(Photo of January snowstorm from Flickr and Wobblymol/Loraine Davis)

The snow is piling up, the cold is harsh. So what does that say about global warming? The deniers say it means the Earth is cooling, not warming. Some of your family and friends may be having serious doubts, too, about whether the planet is really heating up. It’s hard to believe when it’s so darn cold outside.

Well, it is heating up. You can tell people that with confidence. We just finished the warmest decade on record. Arctic summer ice has melted at a record pace. Last year was among the 5 warmest years ever recorded.

We don’t always feel that warmth. It varies from place to place and much of the change is in the oceans.

We’re talking long-term, widespread trends here, not specific weeks or months or specific regions. Even more important – what people find hard to grasp – we’re talking miniscule changes. Fractions of degrees that add up.

Climate scientists are saying if the average world temperature rises more than 2 degrees Celsius (4.6 Fahrenheit) over what it was is pre-industrial times, we are in for cataclysmic climate change.

Some folks wouldn’t even be convinced of global warming if this year was 4.6 F above last year. They are looking for changes they can feel – and feel quickly – like a 10-degree difference for a whole season. If the summer averaged 90 instead of 80, they might believe.

It doesn’t work that way. It happens slowly and insidiously. We need to look, as scientists do, at the slow, long-term changes that are, for example, causing early spring run-off of mountain ice followed by drought; lack of freezing temperatures to kill off pine beetle infestations; and wildfires exploding because the dry season is longer.

Climate isn’t the same thing as weather. Weather can vary widely, and right now it is particularly cold in parts of the Northern Hemisphere, due in large part to something scientists call Arctic Oscillation. That – to put it very simply -- is when pressure pushes cold weather further south than usual. AO is extreme right now. Britain and much of Western Europe are feeling the brunt of it, as are China and Korea. At the same time, though, the west coast of Greenland is having warm rain and parts of Africa are unusually hot. Alaska and northern Canada are warmer than usual, too.

So, what the weather’s like in Montana or Buffalo in a given month doesn’t tell us what’s happening the world over. In fact a Nobel-prize-winning scientist at the University of Montana predicted this week that his state and others in the Rockies are looking at more short winters, more beetle infestations and more wildfires. Steve Running says that while Montana used to have 10-12 sub-zero days a year, now has just 3-4.

That’s what it’s about. A matter of degree. Not weather you can see and feel changing year to year. But trends that recorded data reveal. That’s why we need scientists. And why we need to look at the results of the cumulative changes.

Winter will still be with us, and it may seem just as severe. But it isn’t, and you’d better believe it.

(Sources: Dot Earth, Climate Progress , The Guardian, AP, Missoulian.