Cross-posted from the RYSE blog.
It will soon have been five months since the Deepwater Horizon exploded and the ensuing disaster spilled across headlines. Being particularly awful, the Gulf oil spill occupied the spotlight longer than many catastrophes do. But now the leak is under control; the oil is being cleaned up. Heck, 74 percent just disappeared, according to the government. The media has moved on, and life with it.
Actually, most of the spilled oil was still in the Gulf in early August, when an independent team of oceanographers released their study. But that’s another story. In light of the past summer’s events, you could be forgiven for thinking that oil spills are the worst way fossil fuels impact the ocean. You’d still be wrong, though.
When everything in the oil production process works perfectly, the oil remains safely in the pipelines, on the tankers, in our engines. But when we burn the oil, we create a carbon dioxide “spill” far more widespread than the Deepwater Horizon’s slick. Since you’re reading an environmental blog, you probably know how CO2 affects the climate, so I won’t go into that.
But out of all CO2 released by burning fossil fuels (around six billion tons) only about half increases CO2 levels in the atmosphere. The rest goes into the oceans, where it converts to carbonic acid, raising the water’s acidity. In her book The World is Blue, Sylvia Earle, the world-renowned oceanographer, writes,
A change in acidification can cause trouble for everything from developing fish to jellyfish. Alter the chemistry of the ocean and the entire system shifts.
For example, the structure of coral reefs depends on corals (obviously), as well as red and green algae. These organisms dissolve when acidity reaches a certain level. And if coral reefs collapse, so do the vibrant communities they support.
Ocean acidification could also alter the oxygen and carbon cycles. Photosynthetic marine organisms absorb more carbon and produce more oxygen than do their land-based counterparts. So, by pumping CO2 into the oceans, we are possibly changing the balance of gases in the air we breath.
Returning to Sylvia Earle,
Some natural changes we can predict, but it is impossible to anticipate how fast, or how much will occur as a consequence of tipping the ocean’s chemistry onto a different course.
Examining the past can give us some clues, though. A study published in Nature Geoscience reported that oceans are acidifying ten times faster than they were 55 million years ago, when a mass marine extinction occurred (read Carl Zimmer’s article for details). Of course, CO2 was not the only factor in ancient climates, but one thing continues to be clear: CO2 levels are rising much faster now than they have throughout most of the earth’s history, and speculation is quickly becoming observation.
We’re experimenting with the environment that allows our civilization to thrive. But unlike typical scientists, we only get one chance.
Image: Flickr user Paul Mannix