Archive for March, 2009

Climate Change: Are We Really Responsible?

March 21, 2009

The post that was under this title gave my reaction to a talk by Ken Caldeira, world class scientist. His patient response changed my whole view of the controversy – gotta change the focus.

Rearranging my thoughts,

Jim

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March 16, 2009

The people who discuss the climate change/global warming issue have two opposing beliefs. On one side, people say that we have to do everything possible now to reduce the use of fossil fuel, since by using it we’re putting huge amounts of CO2 into the atmosphere and causing large – likely irreversible – changes in climate. The other side says that the CO2’s not a problem, that the temperature data is inconclusive, that the use of fossil fuel, particularly petroleum, is a problem and we need to stop burning it, but there’s no hurry. We have better things to do now.

What should we do? Here are some arguments and counter arguments from both sides. You decide.

No hurry: The sea level is hardly rising at all. The ice pack on Greenland isn’t shrinking, it’s growing. Melting sea ice doesn’t affect the sea level at all, so we don’t need to worry.
Now: Actually, the sea level is rising, though not so fast as predicted a few years ago. Most of the observed rise is due to expansion of the warmer water. Although Greenland’s temperature has risen significantly, it’s still well below freezing in winter. The increased moisture in the air – caused by higher average temperature – precipitates out as snow. It wasn’t predicted that things would work that way. We’re still in big trouble, though. The ice sheets and sea ice, melting at an increasing rate, are part of a positive feedback process which increases the effect of the CO2 that we’re putting into the atmosphere.

No hurry: We’ve always had droughts, floods, and terrible storms. What we’re seeing now is nothing but natural changes in weather. We’re in a period of unusually strong sunspot activity which raises the temperature. In a few years the sun will settle down and everything will be back to normal.
Now: We are having extremely unusual changes in climate: the changes are definitely not tied to the 9-14 year sunspot cycle since some of the changes haven’t happened for many thousands of years and some extinctions, caused by climate changes rather than loss of habitat, have never happened before.

No hurry: Only a tiny portion of greenhouse gases are man-made, so any change in the climate can’t be caused by the CO2 we’ve added.
Now: Good question. There are a number of positive feedback processes which magnify the effect of anything that is warming the earth. One study suggests that about 50% of the global warming is caused by CO2 build up. Most of the rest is thought to be due to unusually large sunspot activity

No hurry: Places on the planet haven’t gotten warmer, some have even gotten cooler. Therefore the warming isn’t global, isn’t caused by a global phenomenon, and can’t be caused by the CO2 we’re putting into the atmosphere.
Now: Climate changes cause various local temperature changes. It was thought that the temperature in Antarctica was falling, (possibly due to a hole in the ozone layer) but recent data shows that the average temperature there is rising, as in all of the other continents.

No hurry: The famous hockey stick curve shows a sharp rise in temperature but it’s based on faulty analysis. If the temperature is rising at all, it’s just following a natural cycle.
Now: Yes, the hockey stick is wrong. It was based on a faulty analysis of tree ring data. However, satellite data, weather balloon data and direct measurements do show a rise in temperature.

No hurry: Climate is changing and we’re causing it, but it would be too expensive to do anything about it now. If we wait until we get better technology, we can fix it then with a lot less trouble.
Now: This cost-benefit analysis ignores the positive feed back processes that would make it impossible for us ever to get back to the climate we have now – not even close. We can’t afford to waste any more time. We have to act now.


Positive Feedback
When you hum softly into a microphone, your hum comes out of the loudspeaker louder. If you keep humming as you bring the microphone closer and closer to the loudspeaker, nothing happens as the hum gets louder and louder until all of a sudden, blam. The sound gets outrageously loud and you can’t make it softer by moving the microphone back away from the speaker. The technical term for that kind of process is positive feedback. The world has positive feedback processes that make the temperature rise faster and faster in response to added heat. Eventually the change might become irreversible. For example:

As the polar ice melts, it reflects less sunlight back into space and allows more warming of the ocean. The warmer seawater melts more ice and the process goes faster.

The arctic tundra is a huge frozen marsh. As it thaws, its vegetable matter rots faster and releases more methane (a really potent greenhouse gas) that heats things up more. The tundra has been thawing in summer to an unprecedented degree. In fact, the methane bubbles are now so intense that, in some places, the tundra doesn’t even freeze in winter.

March 3, 2009

Oops.  This wasn’t the post I was trying to pull.   I know I should use the help feature, but I’m still used to Microsoft products.