The Rational Optimist_ How Prosperity Evolves - Matt Ridley [158]
Saving ecosystems
Ah, but that is the human race. What about other species? Will the warmth cause a wave of extinctions? Perhaps, but not necessarily. So far, despite two bursts of twentieth-century warming, not a single species has unambiguously been shown to succumb to global climate trends. The golden toad of Costa Rica, sometimes cited as the first casualty, died out either from a fungal disease or because of the drying of its cloud forest, probably caused by deforestation on the lower slopes of its mountain home: a local, not a global cause. The polar bear, still thriving today (eleven of thirteen populations are growing or steady) but threatened by the loss of Arctic sea ice in high summer, may contract its range further north, but it already adapts to ice-free summer months in Hudson’s Bay by fasting on land till the sea re-freezes; and there is good evidence from northern Greenland of a briefly almost ice-free summer sea in the Arctic about 5,500 years ago, during a period that was markedly warmer than today. Arguably, the orang-utan, being devastated by the loss of forest to palm oil bio-fuel plantations in Borneo, is under greater threat from renewable energy than the polar bear is from global warming.
Do not get me wrong, I am not denying that species extinctions are occurring. I passionately believe in saving threatened species from extinction and I have twice worked on projects attempting to rescue endangered species – the cheer pheasant and the lesser florican. But the threats to species are all too prosaic: habitat loss, pollution, invasive competitors and hunting being the same four horsemen of the ecological apocalypse as always. Suddenly many of the big environmental organisations have lost interest in these threats as they chase the illusion of stabilising a climate that was never stable in the past. It is as if the recent emphasis on climate change has sucked the oxygen from the conservation movement. Conservationists, who have done tremendous good over the past half-century protecting and restoring a few wild ecosystems, and encouraging local people to support and value them, risk being betrayed by the new politicised climate campaigners, whose passion for renewable energy is eating into those very ecosystems and drawing funds away from their efforts.
Take coral reefs, which are suffering horribly from pollution, silt, nutrient runoff and fishing – especially the harvesting of herbivorous fishes that otherwise keep reefs clean of algae. Yet environmentalists commonly talk as if climate change is a far greater threat than these, and they are cranking up the apocalyptic statements just as they did wrongly about forests and acid rain. Charlie Veron, an Australian marine biologist: ‘There is no hope of reefs surviving to even mid-century in any form that we now recognise.’ Alex Rogers of the Zoological Society of London pledges ‘an absolute guarantee of their annihilation’. No wiggle room there. It is true that rapidly heating the water by a few degrees can devastate reefs by ‘bleaching’ out the corals’ symbiotic algae, as happened to many reefs in the especially warm El Niño year of 1998. But bleaching depends more on rate of change than absolute temperature. This must be true because nowhere on the planet, not even in the Persian Gulf where water temperatures reach 35°C, is there a sea too warm for coral reefs. Lots of places are too cold for coral reefs – the Galapagos, for example. It is now clear that corals rebound quickly from bleaching episodes, repopulating dead reefs in just a few years, which is presumably how they survived the warming lurches at the end of the last ice age. It is also apparent from recent research that corals become more resilient the more they experience sudden warmings. Some reefs may yet die if the world warms rapidly in the twenty-first century, but others in cooler regions may expand. Local threats are far more immediate than climate change.
Ocean acidification