As we were re-scheduling projects and meetings because of the incoming blizzard, a co-worker from another department asked me:
Are we seeing more frequent and more intense storms because of climate change?
Yes, we are.
Even my colleagues that are not focused on the environment are changing the way they plan for extreme weather. I work for a city, and when I talk with Public Works and Engineering staff, they don’t talk about climate change or why things are changing, they just “know” that when a weather event is described as a “100 year storm” they can expect to see that kind of storm about every 10 years now. They plan that “10 year storms” are something to expect every two or three years. This blizzard has been compared to both the devastating blizzard of 1978 that shut down Boston and the 2013 blizzard which was actually bigger. Two years later and we’ve had yet another record setting blizzard with over 30″ of snow in many communities in Eastern Massachusetts. In the past 12 months, in my city we’ve had three extreme rain events that have resulted in unusual flooding, and one blizzard.
“Climate Change” means exactly that. Our climate is changing. Overall, the global temperatures of the earth is warmer. The average ocean temperatures are warmer. Sea level has risen which means storm surges (such as from Hurricane Sandy) are worse. Warmer oceans means more evaporation which causes more moisture for storms. People like to point to lots of snow and say “see, the planet isn’t warming”, but the reality is, climate change means that specific areas are seeing different climate patterns than they used to see. Here in New England, we’re seeing more precipitation. In the South West United States, they are seeing much less precipitation.
Global warming is like professional athletes on steroids in that a little change makes a big difference, as explained in this video by Jerry Meehl:
One of the changes we are seeing is a shifting of weather patterns. In New England on average, the air temperature is warmer, so we are seeing fewer snow storms and more rain in the winter. The ocean surface temperature near us is warmer than it used to be, so there is more water vapor in the atmosphere. Sometimes, the warmer water is enough to turn what would have been a snow event to rain. Other times, the air is cold enough that we get snow, but because of the increased water content of the atmosphere, it dumps more snow on us at once than it used to. What we are finding is that average winter snowfalls are coming out to be about the same as in the past, but the snow is coming in fewer, more intense bursts.
In recent years, a higher percentage of precipitation in the United States has come in the form of intense single-day events. Nationwide, nine of the top 10 years for extreme one-day precipitation events have occurred since 1990. – EPA Climate Change Indicators in the US, accessed 1/28/15
If you’re interested in reading further about changes in extreme weather events in the United States the 2014 National Climate Assessment was put together by over 300 experts and was extensively reviewed before publication. The web version is easy to read and allows the technically curious to click on the graphs for extensive information about the supporting data.
I am confident in saying that climate change is making our weather more extreme and we should act now to address climate change and adapt to our changing situation. Here is a metaphor from MIT professor Kerry Emanuel:
Suppose observations showed conclusively that the bear population in a particular forest had recently doubled. What would we think of someone who, knowing this, would nevertheless take no extra precautions in walking in the woods unless and until he saw a significant upward trend in the rate at which his neighbors were being mauled by bears?
So yes, climate change is causing us to have more frequent extreme storms.
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