Global Dimming
It made me go back and look at a problem that has been bothering me since Rachel and I first watched An Inconvenient Truth (A+).
The Keeling Curve (wikipedia)
The Keeling Curve is the plot of the levels of CO2 in the atmosphere over time. As you can see it has gone up steadily since 1960 helping to lead to the idea that global warming can be caused by greenhouse gases.
You can also see the data swings up and down within a year. It hits its peak CO2 levels in the spring because that is when the all the leaves come out and start abosrbing the CO2 from the air (good work plants). And begins to rise in the fall when leaves begin to die and the decomposition releases the CO2 back into the air. An important note is that this trend lines up with our seasons here in the North (sorry Australia) because about 3/4 of the total land mass is above the equator.
What has bothered me since watching An Inconvenient Truth is a shift in the calendar year of when the peaks and lows are reached. I started plotting the data, laying the curves of an early year (1960) over top a later year (2006). I personally expected to see a shift in the seasons due to an increase in Global Warming. I thought we'd see the peak CO2 leves be reached earlier in the year (as it got warm earlier for plants to grow) and also the min to be reached later in the year as global warming extened the nice weather in the fall (how great has it been around Halloween?).
I was wrong. (Well only half right).
The Pink line is 1960 data and the Blue line is 2006 data.
As you can kind of see the peak shifts a bit to the left (earlier in the calendar year) going from 1960 Pink to 2006 Blue. This fits well with Global Warming causing an earlier snow melt up north (Canada) and starting the growing season that produces CO2 absorbing leaves.
What has driven me crazy for 6 months is the fact the I was wrong in the Fall. This shows that the Min of CO2 levels is also shifted earlier in time. This means despite possibly warmer weather, trees are losing their leaves earlier (my parents said the leaves are already turing in Boston).
How can this be?
This can be true because of 2 reasons.
1. I suck at biology.
Plants do not lose their leaves due to temperature. They lose their leaves due to a decrease in photosynthesis caused by reduced light. Normally the huge drop off in daylight should occur around Sept 21st (the equinox). But IF Global Dimming were true, this could occur earlier in the year due to pollution reducing light stopping photosynthesis earlier.
2. Global Dimming could be real.
I have seen another PBS special that says we can now measure pollution in Seattle that has made it all the way across the Pacific from China.
What is exciting to me, is that I may have found (am I the first?) pre-existing evidence of Global Dimming in historical data. In the Nova special it was presented as a theory with some evidence it may have decreased ocean temperatures enough to change rain patterns. I emailed some of my charts and thoughts to a professor from Columbia and one from U Wisconsin - Whitewater who were mentioned in the Nova special.
Is any of this legit? I don't know, but it was a lot of fun to work on. And I can sleep a bit better with at least a theory as to why the data drove me crazy for months.
4 comments:
re: #1
according to my a&p professor, biologists do not mix well with chemistryfolk. further, chemists just "screw everything up." the docs words, not mine... but i do believe everything that he says.
One of my profs said Chemical Engineers get paid to make the mess and clean up the mess.
I think once again we need oil prices to keep going up, then the world will become more efficient with their oil. Or else make the people who make the mess pay to clean up the mess too.
Love the analysis.. interesting study. Maybe you will be referenced for providing supporting documentation to a publication in something like "Greenhouse Now" or "Earth, Rain, and Trees" or something like that.
I am impressed. That would have been fun to do.
Perhaps you could get a PhD in environmental studies based on this initial research. If you ever needed a change in careers or something. It would probably be easy to get grant money and other fundings, too, with preliminary research already initiated.
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