I had a wonderful trip recently to Bunaken island off the northern tip of Sulawesi. Despite the garbage floating around on the surface of the water, the diving was wonderful. Highlights included electric crabs, groupers, barracudas and a group of four giant Maori wrasse, which cruised past me in about five metres of water. Quite a sight.
And of course the coral. So many varieties, so beautiful it defies memory, let alone language. I just can’t begin to even remember all the incredible coral forms I saw.
All of it could be gone in my lifetime.
According to mongabay.com, Charlie Veron, former chief scientist at the Australian Institute of Marine Science, “painted a dire outlook for the world’s coral reefs” during a presentation to the Association for Tropical Biology and Conservation, meeting recently in Bali.
Based on projections for atmospheric CO2 concentrations, Veron offered this timescale for reef destruction and the attendant consequences for human society.
- 2015: CO2 levels reach 400 ppm; coral reefs beset by severe bleaching events.
- 2030-2040: CO2 levels reach 450 ppm (limit set in Copenhagen climate change talks); bleaching on nearly an annual basis; ocean acidification begins killing off marine life, especially coral.
- 2060: CO2 levels at 600 ppm; higher water temperatures and acidification will change “everything we know about marine life today”; corals disappear in depths above 10 meters.
- 2110: corals extinct or only askeletal, reefs mainly “wave-washed geological structures” instead of productive ecosystems; mollusks almost gone.
At this point, according to mongabay’s account, “reef-dependent species and human societies will be forever altered”.
Here’s a useful, up-to-date and less dire factsheet from the Australian Institute for Marine Science on the effects of climate change on coral reefs. As a public organisation it’s more measured (conservative?) in its comments than its former chief scientist.
In particular it notes that the effects of climate change are not certain, due to the possibility of adaption: “What is not sufficiently understood are the numerous mechanisms that may enable corals to adapt to new, warmer and potentially acidic conditions”.
It seems likely, though again unproven, that reefs will continue to exist, but we don’t know in what form. We can speculate that they may suffer a loss of diversity and changes in community compositions. We are likely to see shifts in species to different parts of reefs, depending on their adaptation or otherwise to the changing conditions.
Veron ended his talk in Bali by explaining why he left the world of research and took up advocacy. Most of the research currently being conducted, he said, would be out of date by the end of the century.
Maybe he knows something his former employer isn’t prepared to say.
(Photo courtesy of AIMS)