Wednesday, May 13, 2009

Keeping It In Perspective

I recently read a National Geographic article about variations in solar output. Apparently there's been an unexpected /unexplained lull in solar activity lately. We're not quite sure how long it will last or what that will do to the Earth's temperature. Scientists were very careful to point out that this would not necessarily solve the global warming problem. In fact, they seemed quite sure it wouldn't help much, despite headlines hinting at a "little ice age."

Now, I'm what you would call not a global warming skeptic. I don't think the evidence for mankind's role in planetary heating is irrefutable, but it seems strong and the scientific consensus is quite firm. But that's not what this post is about (and please, let's don't debate humanity's role in global warming in the comments today). I just want to take a look at what one of the scientists said.

Mike Lockwood, a solar terrestrial physicist at the University of Southampton in the U.K, explained that a small dip in solar output is not as significant as a large increase in CO2 production. He was quoted as saying:

"I think you have to bear in mind that the CO2 is a good 50 to 60 percent higher than normal, whereas the decline in solar output is a few hundredths of one percent down. I think that helps keep it in perspective."

Um, no it doesn’t. A small percentage of a large number might be much larger than a large percentage of a small number. For example: one hundredth of one percent of 100,000 is 10, but 50 percent of 1 is only .5. 

So, if the sun's huge output is decreased by a tiny fraction, that could theoretically mean the amount of heat it is not sending our way could equal or exceed the extra amount of heat being retained by increases in greenhouse gases. It might be sending 10 fewer units of heat our way, while the increased amount of C02 in the atmosphere is saving an extra 0.5 units. That's a net loss of 9.5, for those of you keeping score at home. Keep in mind, these numbers are notional - I'm just trying to make the point that his explanation doesn't "keep it in perspective" the way he thinks it does. And it bugs me that he thinks it does.

I suspect Dr. Lockwood actually did the math before he concluded that the solar lull's affect does not balance out the impact of all that extra C02. He's a solar terrestrial physicist, for goodness sake. Those guys aren't shy about doing the math. I just wish his explanation of how these two quantities relate to each other was (with all due respect) a little more correct.

1 comment:

Mark said...

Them dern fizziksist! Always confusicating mah brainz!

How 'bout this for perspective:
If I take 95% of the water out of the glass on my desk, and pour 0.0001% of the ocean into the glass, surely I will need a mop.