It's worth noting that a world without coral reefs is hardly unprecedented. Approximately 14,000 years ago, every coral reef in the world would have been destro

It's worth noting that a world without coral reefs is hardly unprecedented. Approximately 14,000 years ago, every coral reef in the world would have been destroyed by Meltwater Pulse 1A[1], an event which caused sea levels to rise by 20 metres in just a few hundred years. Although this must have caused the demise of the complex reef ecosystems, coral itself survived, presumably as isolated individuals and very small clusters. Afterwards, sea levels continued to rise rapidly, and the large reefs that we have today could not become established until about 7,000 years ago, when the sea levels finally stabilised. The corresponding ecosystems have evolved only since then. For this reason, I am mostly unconvinced that the (admittedly horrible) disruption which we are causing today will irrevocably knock things back to a precambrian state. When you look at history of our planet over evolutionary timescales, you see all kinds of disruptive events -- rapidly rising or falling seas; bolide impacts as powerful as tens of millions of nuclear bombs -- which the planet has managed to shrug off with apparent ease. With one exception, most of the harm we are causing seems to be along these lines. So even if the great reefs die off, then my expectation would be that coral itself would continue to survive in niches. 10,000 years from now -- long after we've wised up or died off -- there could very well be great reefs again, and our disruption would be relegated to a small blip in the overall evolutionary record. The planet's losses will ultimately be minimal; the real losers will be our children, who will inherit a less beautiful and wondrous world than the one we know. I've swum through coral reefs, and it's painful to think that the next few dozen generations won't be able to experience that kind of beauty. But from the planet's perspective -- looking at evolutionary timescales -- this may not be a particularly big deal. The one real and substantial caveat to my nonchalance is ocean acidification. It is truly global compared to other forms of ocean pollution, acts as a disruptor to individual cells rather than to the (more resilient than we give them credit for) ecosystem relationships, and is making an excursion that may be unprecedented in the past 300 million years. In contrast to things like changes in sea levels and temperatures -- which actually happen all the time when you take the long view -- evolutionary timescales give no assurance that ocean acidification will be a survivable event. It is something that merits a much higher level of attention than it's getting. [1] http://en.wikipedia.org/wiki/Meltwater_pulse_1A http://en.wikipedia.org/wiki/Meltwater_pulse_1A