Monday, July 13, 2009

Another Cost of Climate Change - Coral Reef Bleaching

Over at PLoS ONE, there is a new study out that predicts some pretty dire consequences for coral reef communities from continued sea temperature rise. It seems that if one looks at the impact of green house gasses on ocean surface temperatures (which are a major cause of coral bleaching), the two best climate models from NOAA’s Geophysical Fluid Dynamics Laboratory predict a serious increase in temperature caused bleaching through 2100. The usual scientific caveats are applied, but the bottom line is real, and dire:

Humans had put enough greenhouse gasses (including Carbon Dioxide) into the atmosphere by 2000 to seriously imperil the world’s coral reef communities due to temperature-induced bleaching. Even if we do things now to get back to or below that level, the lag time in climate systems will not stop massive coral bleaching for most of the rest of this century.

Um, ok, so what you may ask. What is bleaching anyway, and why should I care? Coral Bleaching is when a coral head, or an entire reef, releases or sloughs off its collection of symbiotic algae from within each coral polyp. Not only does this remove the color of the coral, is usually leads to death of the coral because the algae are an important food producer for the polyps. So, bleaching events are bad for reefs physically.

On the human side of things, bleaching events are bad economically as well. In the aggregate, losses to human communities that rely on reefs for economic success may range from $3.35 Billion to $4.87 Billion per year. This would include the loss of recreational and commercial fisheries harvests, loss of commercial SCUBA diving and snorkeling tourists, and the very real impacts of increased storm damage to coastal areas as reefs decay. Much of that impact would be felt close to the U.S., most notably in the Caribbean islands.

Why am I drawing this to your attention? For the same reason that I keep linking to old reports from Congress’ defunct Office of Technological Assessment – to prove the point that our global climate crisis is very real, isn’t a new phenomena, and requires strong action lest we loose some or all of our Earth’s most precious resources. I also keep drawing it to your attention because when I hear how "expensive" actions to arrest global climate change are supposed to be, I shudder. The balance sheet of inaction is rapidly filling up with entries like this. How much does inaction have to cost before we do something?


Thomas Joseph said...

Is the scientific community doing anything to preserve coral reefs outside of their natural habitat? Is it possible to transplant coral reefs into aquariums (for example) and reintroduce them when we finally get our act together and get things straightened out (whenever that may be)?

Philip H. said...

There has been a lot of coral aquaculture in recent years - there's even a move afoot in Florida to grow corals for repair of ship damaged reefs. The problem with corals, however, is that they are surprisingly intolerant of too wide a range in a variety of physical conditions. So keeping large numbers of them in aquaria is actually rather labor intensive due to the constant monitoring and adjustemnt required. Hence a lot of the "coral" you see in aquaria as large exhidits is made of well painted concrete with a few real corals thrown in.