Dear readers,
For this entry I will not discuss my favorite topic (the oceans), but will focus on geological climate change. My reasoning is that to discuss current climate change, you must understand the past. This geological data is also what frequently gets cited in arguments against anthropogenic climate change. For this reason alone, I think it's very important that we all understand the data. So, I apologize for leaving the oceans, but I can promise a big ocean perspective payoff in the next entry, because, as I said before, it all leads back to the oceans.
The topic of anthropogenic climate change is particularly controversial in the field of paleoclimatology. Paleoclimatologists are scientists who study the climate over the geological history of the Earth, and can therefore compare current climate changes with those in the distant past. They are able to do this by correlating the temperature of the earth with data from ancient microfossils, sediment layers, and gas bubbles trapped in ice sheets.
One thing all paleoclimatologists agree on is that Earth's climate is variable. The graph below shows the variation in temperature over 542 million years, with the current rise in temperatures on the far right. What paleoclimatologists do not agree on is if increasing carbon dioxide (CO2) levels can be indicted with the temperature rise, because, in the past, natural temperature rise led to increased CO2 levels (not the other way around). This conclusion, however, does not take into account positive feedback loops in the biosphere or the Industrial Revolution.
(Image credit: http://upload.wikimedia.org/wikipedia/commons/f/f5/All_palaeotemps.png - copy and paste link into browser to increase image size)
Come back next time to see how this debate ties back into our oceans!
-N. Gallo
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