Sunday, April 4, 2010

Hip boots and sandbags: Climate change isn't coming--it's here

An odd piece in the great debate over climate change is that some of us are still arguing about whether it is going to happen.

The discussion is akin to two guys standing up to their knees in rising flood waters, debating whether it might rain.

In case someone hasn't yet noticed, climate change is already here.

(Image: This is a NOAA compilation of 92 different studies of climate reconstructions, part of NOAA's Paleoclimate Network (PCN). It records how temperatures differ from the norm over time. You can find more here. The reconstructions are from global studies of tree rings, glacier cores, stalagmite measurements, lake sediments and even the historical dates of grape harvests. Source: Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.)

Climate science is extremely complex, but there are some simple basic basics. Here are three.

1. A 50-year-long series of high-elevation measurements at Mauna Loa Observatory show that the amount of carbon dioxide in the atmosphere is increasing, to levels not seen in a very long time.

2. Many, many climate models predict that this leads to a warmer atmosphere.

3. And, as predicted, it has warmed and continues to warm. We are able to measure the warmer atmosphere, both directly and indirectly. The most reliable air temperatures show a significant warming trend. The southern boundary of permafrost is moving north. Spring is coming earlier. The deep ocean is warming.

Here's a pertinent bit of information on the coming of spring, from Berlin's Humboldt University:

“The growing season in Europe, here defined as the average time between leafing and leaf fall of selected trees, has extended by 11 days in the last 30 years, mainly because leaf infolding begins earlier by about 2.7 days per decade in spring. Events such as the blossoming of fruit trees in Germany (apple, cherry, etc.) were affected by the higher temperatures in the end of winter and in the early spring. An increase of average air temperature between February and April by 1 degree Celsius lead to an advanced leaf unfolding or blossom of trees in Europe and Germany by about one week.”

Some media are still trying to frame this as a debate over opposite but equally supportable sides. Which requires a remarkable suspension of reality, or it requires simply not paying attention.. We don't customarily cite other blogs, but Climate Progress has interesting insight here.

If you need to argue, there are lots of things to argue about. Not whether sea levels are rising, but how fast. Not whether oceans are warming, but how much. And whether as a society we should be doing more to prepare ourselves for the predictable further impacts, or doing more to address the possible ways of reversing the trend, or both.

Climate change is here. It's time to stop talking about whether it's going to rain, and start serious talk about hip boots and sandbags.

© Jan TenBruggencate 2010.

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