Log in

No account? Create an account
The Mad Schemes of Dr. Tectonic [entries|archive|friends|userinfo]

[ userinfo | livejournal userinfo ]
[ archive | journal archive ]

Getting It [Apr. 17th, 2007|03:41 pm]
On Friday, I went to two talks about global warming. The first was over at CU, part of the Conference on World Affairs, by former congressman Tim Wirth. What I found really interesting about it was that he spent a few minutes at the beginning going over the whole (by now very tiresome to me) "global warming is bad" thing. What I found remarkable is that he then stopped talking about it, and spent the rest of his time talking about what we can do about it. Moreover, he really emphasized that we need to not regard it as an insurmountable challenge, but as a situation where necessary change is also an opportunity.

The second talk was here at work, by Amanda Staudt, who works for the National Wildlife Federation, and was about the recent dramatic shift in U.S. attitudes toward climate change. Among other things, she talked about hearings about the subject on Capitol Hill, and already this year there have been, like, ten times as many congressional hearings on the subject as there used to be in a typical year. (I know of three people in my department who are flying to DC this week for hearings.)

So, that's an impressive and dramatic shift.

More impressive? Even folks like Newt Gingrich get it now. (Boston Glob article, registration and linkrot warning)
"Gingrich praised Kerry's recently released book about environmentalism, acknowledged that global warming is real, and offered what amounted to an unexpected apology for his party's inaction on curtailing greenhouse gas emissions."



I think it's going to take a little while to get over the shock and move on to discussing what to do about it. We're not used to having people actually listen...

[User Picture]From: dr_tectonic
2007-04-19 05:07 am (UTC)
A fine question!

I'm not really qualified to throw numbers around, but I'll take a stab at it. What I can say with confidence is that I believe these figures are a pretty accurate representation of reality.

Of the climate forcings listed there, the only one not affected by human activity is the sun's output. There are varying levels of uncertainty about exactly how much we affect all the others, but the most clear-cut component is CO2. Increases in CO2 levels are clearly the result of human activity (history of industrialization, isotope ratios, and raw quantities all line up quite nicely), it's the biggest single climate forcing factor, and we're well on our way to doubling CO2 concentrations in the atmosphere. (Doubling is the target for stabilization, and it's an ambitious target that will take a lot of work.)

So, okay, there's a lot going on there, but let's look just at CO2 and solar activity. Solar variability for the 20th century is less than 1%, I gather, so that's about 0.03 W/m2, while doubling the CO2 component would bring you from 1.5 to 3. So that looks like about 2 orders of magnitude to me, give or take. And that's just CO2; add in the other greenhouse gases and it's even more imbalanced on the side of human activity.

There is definitely a solar component to climate change, but it's comparatively small. This is a question that's been resolved only in the last few years, so there was a lot of argument about it not too long ago. I remember a presentation at work a couple years ago where they were talking about the famous "hockey-stick" graph, and explaining that even including solar variability, the only way the modelers could get the models to track with the observed data at all was by including anthropogenic effects.

Does that summarize pretty well?
(Reply) (Parent) (Thread)
[User Picture]From: backrubbear
2007-04-20 01:28 pm (UTC)
It does, thanks. People were throwing around a lot of opinions - some with data, but not very good about pointing out their sources. This looks like the source for at least 1/3 of the opinion on that particular list.
(Reply) (Parent) (Thread)