In the midst of all the grim talk about runaway global warming, there is an upbeat note -- sort of. Certain types of coral reefs appear to be more adaptable to climate change pressures than first thought.
The good news about arguably the most biologically productive ecosystems on the planet comes with a major caveat. Corals' ability to tolerate climate-related rising sea water temperatures is not open-ended. Scientists don't know the threshold at which these marine organisms can no longer adapt. The best that can be said -- and it is not inconsequential -- is that these corals' sturdy genetic structure buys us some time to slow the pace of global warming, and in the process, assure the survival of the reefs.
Disappearance of the world's coral reefs would be calamitous. One-third of all the ocean fish spawn and mature in the shelter of the biologically diverse reefs and provide basic sustenance for more than a billion people. The Great Barrier Reef alone is estimated to be worth $6 billion annually to the Australian economy. Many of the reefs serve as valuable protective buffers against major storms striking coastal areas.
These invaluable benefits notwithstanding, 25 percent of the world's coral reefs have already vanished, and 75 percent of those remaining are in various stages of severe stress. At the present rate of loss, two-thirds of those deteriorating systems are projected to be gone by 2050. The mortality is primarily due to some coral species' inability to adapt to climate change- related warmer and increasingly acidic waters, although coastal pollution, overfishing, and abusive tourism practices are also complicit.
Despite such losses, scientists have found some reason for hope, at least in the short term, and if our cards are played right, in the long term as well. Researchers have discovered that certain healthy coral reefs can revive sickly ones through transplantation. Some species of coral even thrive under exposure to moderate rises in water temperature and acidity. In another breakthrough, scientists have come across corals that have survived uncomfortable seawater temperature rise in the Virgin Islands by attaching to the roots of semi-submerged coastal mangrove forests. With the shade of the trees sheltering the waters from the full impacts of global warming, the corals have flourished.
Again, the unanswered question is how resilient are the hardiest corals. What does seem apparent is that if given half a chance, many species of coral will survive. To give them that opportunity, humanity must find an expeditious way to dramatically reduce carbon emissions, curb coastal pollution, end overfishing, and crack down on tourism malpractice.
Nature does not always give us the luxury of extra time to make amends. Let's not blow it.