It has been a pretty exciting couple of weeks for carbon dioxide. The infamous gas celebrated a stunning victory last week against its long time rival, water vapor, for control of the Earth's climate. According to a study published at NASA's Goddard Institute for Space Studies (GISS), which examined the role that various gases play in the greenhouse effect, the planet's temperature ultimately depends on the atmospheric levels of carbon dioxide. Better luck next time, water! Water vapor and clouds still play a major role in global warming, but without non-condensing gases like CO2 and methane, they cannot uphold the Earth's greenhouse effect. This leaves water in distant second place, a loss as crushing as that suffered by Carolina in Sunday's 5-1 Vancouver game.
Note: C is also the atomic symbol for carbon. Coincidence? I think not!
This puts an end (or should, at least) to theory that water vapor, being more abundant in the atmosphere than carbon dioxide, has greater control over the Earth's temperature (and, by extension, that our efforts to reduce carbon emissions are pointless).
To add insult to injury, it turns out that global warming (which as we now know is driven by CO2) has actually sped up the global water cycle. An earlier study from the University of California showed that river runoff into the ocean had increased by 1.5 percent annually over the twelve years from 1994-2006. Aside from increased flooding along rivers, this acceleration could lead to more intense storms (including Hurricanes – I haven't forgotten you yet, Carolina) in some areas and droughts in others.
For those of you keeping score at home, it's now 2-0 for carbon dioxide.
But the game isn't over yet, and CO2 still has a hat trick up its sleeve. As my colleague John pointed out a few weeks back, CO2 is also the progenitor of global warming's evil twin: Ocean Acidification. More acidic waters are a direct threat not only to shellfish and coral, but even to top predators like sharks. Even more frightening, increased acidity in the ocean is expected to have dire repercussions for pteropods, tiny marine snails which support pretty much the entire Arctic marine food-web! There is also good evidence to suggest that higher levels of CO2 could destroy reproduction in krill, the tiny prawn-like creatures upon which most animals in Antarctic waters rely.
So let us sum up: carbon dioxide concentrations in the atmosphere are increasing global temperatures, accelerating the global water cycle (indirectly, through global warming), and making the oceans more acidic. If I were water, or (more specifically) the proponents of water vapor as the main cause of climate change, I would be heading back to North Carolina with my tail between my legs.