The messiness surrounding weather and climate
I’m gazing out the window of my family’s house in North Carolina where 8.5 inches of snow dropped suddenly late Christmas Day. There hasn’t been a snowflake on Christmas in some 50 years, according to the weather records that were meticulously researched by my snow-crazed family.
It’s been a white Christmas all up and down the East Coast, making it easy to forget (or scoff off) that 2010 will be one of the warmest years on record by world meteorological standards. The distinction between weather and climate has featured center-stage every time there’s a hurricane, snowstorm, or drought and both sides can overstate the signs in favor or against climate change.
It can be confusing because climate is the accumulation of weather patterns over a long period of time. Yet it can be hard to see the anomalies for what they are. Eric Fetzer at NASA’s Jet Propulsion Laboratory has an insightful metaphor. He says:
“We all know smokers who live into their eighties, and health nuts who drop dead in their forties, but these examples are not taken seriously in discussion of health issues. Most people understand and accept anomalies in fields like health care and economics, and we need to do the same with climate issues.”
Yet an interesting twist on climate change is that some of these odd weather patterns may be pointing to the emergence of a new climate in certain parts of the world. Time Magazine took a look at the cold snaps that have been hitting the East Coast and Europe in recent years in juxtaposition to the epic warming of the Arctic. It explored the evidence behind changes in the jet stream due to alterations in high pressure that affect wind patterns in the warming Arctic. Cold air is seeping into the mid-latitudes making for extreme cold and snowy weather events.
I always get confused with talk about air pressure changes, so this analogy by Wunder Blog was helpful to me. Think of opening the door to your refrigerator. Inside, the temperature will warm but outside the doors will get cooler. Keeping the cold air where it ought to be — in the Arctic – will only happen if the doors are shut again.
In the end, weather does say something about the climate. Only you have to know a lot more about the underlying causes to distinguish between a freak event and an emerging pattern that signals a long term change.