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On the one hand the public has been listening to dire predictions about the effects of Global Warming, but on the other hand the public is also aware that we’ve only been able to muster about one little degree Celsius of actual warming since the industrial revolution. And when scientists talk about future warming, they’re talking “OMG let’s not get above two degrees!” No wonder over half the people in the United States don’t think Global Warming is a serious issue, and the number of skeptics has actually been on the rise for the last five years (Gallop Poll, March 2010).
I get that. One little degree doesn't sound like much - and in the context of day-to-day weather, it's not. What we can and should be getting excited about (and talking about) is what’s behind that one-degree rise: heat energy, and lots of it. It's not just the temperature in Minneapolis that's up a degree today. It's that the temperature of the entire planet is up one degree.
Let’s look at two analogies:
- If you're sitting in the sun, and the skin temperature on your arm goes up 5 degrees - no problem, you're tanning. But if your body temperature goes up 5 degrees — you take your fever to the emergency room. Local temperature rise - no problem. All-body temperature rise — big problem.
- On a global scale, suppose someone tells you that ocean levels rose one inch — big deal, right? But now lets look at how much water it takes to raise ocean levels one inch. I did the math – it’s about 2,200 cubic miles. It would take over 10 million years for the Mississippi River, with zero losses to evaporation, to raise ocean levels that one little inch. Small rise on the ruler, BIG rise in the amount of water.
Back to temperature: to raise the temperature of the planet one degree Celsius requires about 5 exaJoules (5 with 18 zeros after it) of energy. That’s the equivalent to the entire energy consumption of the US for 4 million years. Small rise on the thermometer, BIG rise in the amount of energy.
So, yeah. One degree is all Global Warming’s got. But that one degree packs a heck of a punch. Look at the weather this year. And last year. And the year before that.
The really bad news is that we're adding heat at an accelerating rate. Look at the Global Warming projections on the chart at right. The entire change in global temperature in the one hundred years from 1900 to 2000 is about that one little degree Celsius. Now look at the temperature rises projected for the next 100 years. The most conservative model has a 2 degree Celsius increase – double what we did in the last century. And the most worrisome model: five times the amount of heat energy added to the system.
So things aren't just getting worse. They're getting worse faster. And if one degree worth of heat energy is already creating the horrible hurricanes, the devastating droughts, and the wild wildfire seasons we've experienced the last several years, what will two degrees bring us? Five degrees anyone?
Graph caption: There are several global climate modeling systems in use by scientists — they make different assumptions and focus on different things. The colored lines on the graph represent forecasts of global temperature rise by the 8 models used by the Intergovernmental Panel on Climate Change, the international body of scientists monitoring climate change. More at http://bit.ly/Myo1Lj.
Next time: The Global Warming and Weather: Yes, Virginia, There Is a Connection
Michael Kelberer has been reporting on climate change since 2007.