Who do you believe when the data is conflicting? - Scott Hildreth

Some of the scientists, I believe, haven’t they been changing their opinion a little bit on global warming? There’s a lot of differing opinions and before we react I think it’s best to have the full accounting, full understanding of what’s taking place.

GEORGE W. BUSH, presidential debate, Oct. 11, 2000

Yes, there is still much about global warming we have to learn and research should continue. But the longer we delay, the more CO2 will build up in the atmosphere. It stays there a long time. If we wait too long before acting, we will pass a point of no return and lock ourselves into centuries of global warming. We could pass one of those dangerous tipping points that could make life very difficult. It's a risk we shouldn't take.

JIM DIPESO, speech, May 1, 2003

Over the past few weeks, you've read a lot about Global Warming, and at the same time, hopefully come to understand science a bit better, too. While many scientists around the world have expressed concern about the reality of global warming, and many respected organizations of scientists have reached a consensus that human activity has exacerbated the problem, there are still critics who say that the science is not clear, or that the entire issue is a hoax cooked up to defraud the public into voting for more government spending. Since every scientific measurement has uncertainty, some scientists and critics have claimed that the data is not yet sufficient to affix causes. But should we wait for more, better science before doing something?

1. Background Investigation

Read this short article by a climate scientist about why the issue of what, or who, is causing global warming is not so easy to answer:

Weart, S. (2008, 8 September) Simple Question, Simple Answer....Not. RealClimate.org. Retrieved 21 September 2008 from http://www.realclimate.org/index.php/archives/2008/09/simple-question-simple-answer-no/

2. Watch YouTube video

Now watch the following short video clip - preferably with friends and/or family.

Craven, G. (2007) How It All Ends http://www.youtube.com/watch?v=mF_anaVcCXg. Note that this is a summary of the issue, and that you can view additional and related videos by Craven and others at the YouTube website. I highly recommend watching more that just this videoclip.

In a short essay of at least 250 words, summarize:

a) What did you think of the video? Does Craven's approach make sense, or do you think it too simplistic? Why?

b) Given that science is by its nature uncertain, how do you think we should proceed on the issue? Should we wait for more science to be done? Should we act?

c) What questions do you still have about the issue?