The End of a Stable Climate?
On March 8th (yes, I know, I’m a little late), researches at Oregon State University and Havard University published the most comprehensive reconstruction of global temperatures ever done, going back 11,300 years. When combined with projected warming this century, the results are rather astonishing:
(I’m reminded of a Sesame Street song: One of these things just doesn’t belong here. One of these things just isn’t the same!)
The reconstruction illustrates many important points. First, our modern society has evolved (over the past 10,000 years) in a relatively stable climate. Second, the planet is warmer today than it has been during 70 to 80 percent of the last 11,300 years. Interestingly, during the past 5,000 years, the Earth cooled about 0.8 degrees Celsius (1.3 degrees Fahrenheit). However, it has warmed by about the same amount in only 100 years. In other words, due to our emissions of carbon dioxide (and other greenhouse gases), the temperature in the last 100 years has changed 50 times faster than the period during which our modern civilization (and the agriculture that feeds it) developed.
And it is this rate of change that scientists say is most important. According to the lead author of the study, Shaun Marcott, “It’s really the rates of change here that’s amazing and atypical. Even in the ice age the global temperature never changed this quickly.”
Climatologist Micheal Mann also see the importance of the rate of warming:
This is an important paper. The key take home conclusion is that the rate and magnitude of recent global warmth appears unprecedented for *at least* the past 4K and the rate *at least* the past 11K. We know that there were periods in the past that were warmer than today, for example the early Cretaceous period 100 million yr ago. The real issue, from a climate change impacts point of view, is the rate of change—because that’s what challenges our adaptive capacity. And this paper suggests that the current rate has no precedent as far back as we can go w/ any confidence—11 kyr arguably, based on this study.
I would add that this incredible rate of change not only challenges our adaptive capacity, but nature’s as well. Evolution through natural selection is a process that, for the most part, happens slowly. Over thousands, if not millions of years. That is why scientists believe that 40 to 70% of all species on Earth could go extinct if the globe warms by 4 degrees C (above pre industrial temperatures).
We know what the threat is (climate change).
We know what the cause is (emissions of greenhouse gases)
We know what the solutions are (renewable energy, energy efficiency and energy conservation).
We have the technology (wind, solar, geothermal, smart grids, electricity-powered transportation, LIGHT SWITCHES!).
All we need now is the political will to act.
I think I’m going to go write a letter to my local MP.