Sunday, July 12, 2009 5 comments ++[ CLICK TO COMMENT ]++

Sunday Spectacle XVII

Greenhouse Gas Emissions





(Source: From Kick the Habit: A UN Guide to Climate Neutrality (2009). UNEP/GRID-Arendal.)

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5 Response to Sunday Spectacle XVII

Daniel M. Ryan
July 12, 2009 at 4:37 PM

What about natural sources?

Sivaram
July 12, 2009 at 9:20 PM

I think this is just what humans have control over. Natural sources are usually ignored because we have no control over them. I suspect natural sources will be flat in the long run (greenhouse gases from nature may increase but then they also decrease.) In any case, I'm not too knowledgeabout about this but I would imagine that all the incremental greenhouse gases in the last few hundread years come from human activity and not nature (I need to double-check that but that would be my guess).

Daniel M. Ryan
July 13, 2009 at 12:41 AM

Actually, CO2 levels have varied widely over the millenia. Here's one "fun fact" that I still remember, perhaps because of its dramatic nature:

There has to be at least 200 ppm of CO2 in the atmosphere or plants die off wholesale - including the plants we need to eat. Just before the Industrial Revolution started, the ambient CO2 level sunk to near that level and later rose.

Anyways, here's a graph of CO2 and temperature levels over the past 400,000 years:

http://www.heartland.org/policybot/results/22787/Report_Temperature_Changes_Precede_CO2_Changes.html 

Sivaram
July 13, 2009 at 11:04 AM

Who knows how much carbon dixoide impacts temperature but humans have been emitting a ton of it lately. Check out this chart from Wikipedia. The question is whether the significant increase since the Industrial Revolution has no impact on nature or not.

I think people pay too much attention to the temperature impact. First of all, Climate Change, if it actually ends up being true, will not raise temperature everywhere. Some regions will actually get colder. You may get unusually warm winters in a cold region but you may also get unusually cold summer in some warm region. When someone is measuring data--this goes for all those ancient ice samples and other measures of the past--you are really looking at a specific region of the world. For instance, I don't follow this topic but I haven't seen too many measurements coming from the tropics. It makes sense because the ice core samples that are used to analyze the distant past do not exist in the tropics.

The second problem with looking at temperature is that, even a relatively pessimistic case, if greenhouse effect takes effect, results in earth's temperature going up by only 1 degree. This is a huge thing, especially for temperature-sensitive reptiles and the like, but it is so small in the grand scheme of things. What is the margin of error in such a measurement? I'm not an expert on climatology but I wonder if the error tolerance on the measuring instruments may make the number somewhat unreliable.

Overall, regardless of what thinks of this issue, very little is going to be done until people start suffering. Right now, a lot of poor countries, like China and India, will not support any attempt to curb emissions. Ironically, those are the countries that will suffer terribly if Climate Change ends up being true. So, until the whole world reaches some consensus, nothing is going to happen...

Daniel M. Ryan
July 13, 2009 at 2:16 PM

Who know, indeed. Here's one to add to your doesn't-make-sense file: my home country (Canada) might very well benefit from global warming. To take a single example: there are lots of abandoned farms that couldn't pay because the growing season is too short where they are. A sustained burst of global warming would lengthen the growing season to make some of them carry their weight, profit-wise. Less prophetically, a lot of fossil fuels come from Canada. So, you'd think that a lot of my fellow Canadians would be with the developed nations in terms of minimizing the significance.

And yet, they're not - at least not in the political class.

There's a lot of irrationality surrounding this issue...had Mackay been around today, he'd be writing about it.

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