Tuesday, April 14, 2009

Dramatic greenhouse cuts necessary and also possible

If you want to help save the world as we know it, it will take more than incremental changes, according to new research.

A switch from an 18-mile-per-gallon car to a 20 mpg car won't do it. That's just a 10 percent improvement. We need 70 percent, according to new research.

(Image: New computer simulations show the extent that average air temperatures at Earth's surface could warm by 2080-2099 compared to 1980-1999, if (top) greenhouse gases emissions continue to climb at current rates, or if (bottom) society cuts emissions by 70 percent. In the latter case, temperatures rise by less than 2°C (3.6°F) across nearly all of Earth's populated areas. However, unchecked emissions could lead to warming of 3°C (5.4°F) or more across parts of Europe, Asia, North America, and Australia. (Graphic courtesy Geophysical Research Letters, modified by UCAR.)

New research, as the caption indicates, is suggesting we need a 70 percent cut in greenhouse gases to stabilize climate change, reduce flooding potential in Waikiki, minimize droughts, and so forth.

For the car, 70 percent means going from an 18 miles per gallon to a 60 miles per gallon vehicle--but that's just one way to do it.

For the 60 watt lightbulb, switching from incandescent to fluorescent will work, since it cuts emissions about three-quarters for the same amount of light.

In other areas, the saving are more difficult to attain, and more difficult to calculate. You can't readily cut your food consumption by 70 percent, but by eating locally grown produce, you could reduce significantly the among of travel energy inherent at the kitchen table, for instance.

It still won't prevent the loss of the world as we know it, but it could help keep the world from being too different, said researchers who report in the April 21 issue of Geophysical Research Letters, a publication of the American Geophysical Union (AGU).

"This research indicates that we can no longer avoid significant warming during this century. But, if the world were to implement this level of emission cuts, we could stabilize the threat of climate change and avoid catastrophe," said lead author Warren Washington, a scientist with the National Center for Atmospheric Research (NCAR).

The AGU in a press release noted that global temperatures are up nearly 1.8 degrees Fahrenheit in the last century, much (but not all) of it the result of human activities. And there's a suggestion that this level of change may put the globe near some kind of climate tipping point.

The paper is entitled, "How much climate change can be avoided by mitigation?" Its authors are Washington, Gerald A. Meehl, Haiyan Teng, David Lawrence, Lawrence Buja and W. Gary Strand, all of NCAR in Colorado; Reto Knutti: Institute for Atmospheric and Climate Science, ETH, Zurich, Switzerland; and Claudia Tebaldi: Climate Central, Princeton, New Jersey and Palo Alto, California.

Computerized climate models are favorite targets for frothing climate change deniers, but Washington and his associates got some interesting information out of them, using NCAR's Community Climate System Model, running on supercomputers.

They assumed that the amount of carbon dioxide in the atmosphere, which has already risen from 280 to 380 parts per million since the start of the industrial age, will rise to 450. That's viewed by the U.S. Climate Change Science Program as a reachable goal if significant conservation programs are enacted. If not, the numbers is 750 by 2100.

At 450, they calculated that temperatures would go up another degree Fahrenheit by 2100, that sea level rise would still happen but could be reduced by three inches or so. Fisheries would be preserved by fish not moving to new waters where temperatures were more to their liking. And dramatic droughts in the American Southwest and floods in the Northeast could be limited.

The result, the authors say: “The climate system would stabilize by about 2100, instead of continuing to warm.”

"This study provides some hope that we can avoid the worst impacts of climate change -- if society can cut emissions substantially over the next several decades and continue major cuts through the century," Washington said.

It's not impossible; not even that difficult. If you want to keep the gas guzzler, just invite your neighbors to commute to work with you. Put three one-person-per-car commuters into a single vehicle together, and you cut emissions close to two-thirds.

And it may help prevent the accident you get into, chatting with each other on the cell phone while commuting.

How many other ideas for 70 percent cuts in energy production can you come up with?

© Jan TenBruggencate 2009

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