Dear Dr Rogers,
The plight of corals has been highlighted by the Guardian article (see forwarded below). I'm not an expert on corals, but there seem to be at least three major threats: * ocean acidification * warming sea surface temperatures * rapid sea level rise 1. As regards ocean acidification, you seem to suggest that the current level of CO2 is already too high. How long have we got to get it down to 350 ppm? 2. How much effect does the warming have? Since warmer water can hold less CO2, it is therefore less acidic, so this must to some extent negate the increase in CO2. 3. About 14,000 years ago there was a meltwater event with sea level rise around 20 metres in 400 years [1]. Hansen is worried that, with current emissions trajectory, we could have a metre or even metres of sea level rise this century. Indeed, if Greenland and West Antarctic ice sheets (GIS/WAIS) were both to disintegrate, we'd get about 15 metres. There has been bad news from Greenland recently [2] [3] and Antarctic [4]. The possibility of geoengineering arises, both to remove CO2 from the atmosphere and to for solar radiation management (SRM). It has been proposed to use SRM to cool the Arctic and save the Arctic sea ice [5]. There are currently two principle candidates for SRM - stratospheric sulphate aerosols and marine cloud brightening [6]. Could the latter be used for local cooling and help to save particular coral reefs? Kind regards, John Nissen, Chiswick, London W4 [1] James Hansen, e.g. in: http://climateandcapitalism.com/?p=148 [2] http://www.earth-stream.com/Earth/Continents/Japan/Massive-Greenland-Glacier-Melting-At-Troublesome-Pace_18_197_681_182823.html [3] http://www.newscientist.com/article/dn17465-arctic-glacier-to-lose-manhattansized-tongue.html?DCMP=OTC-rss&nsref=environment [4] For example see "recent glacier acceleration" in: http://en.wikipedia.org/wiki/Pine_Island_Glacier [5] See "Part C" in the open letter to Dr Pachauri: http://geo-engineering.blogspot.com/2009/03/open-letter-to-dr-pachauri.html [6] See special issue of Phil Trans of Royal Society, A, referenced here: http://en.wikipedia.org/wiki/List_of_proposed_geoengineering_projects --- Alvia Gaskill wrote: > Here it is from the Guardian. He appears to be referring to measures to > remove the legacy CO2, but isn't specific. > > http://www.guardian.co.uk/environment/2009/jul/07/coral-attenborough > > Coral condemned to extinction by CO2 levels, warns Attenborough > Coral is the canary in the cage as damage can be seen most quickly, veteran > naturalist tells Royal Society > > a.. Alok Jha > > b.. guardian.co.uk, Tuesday 7 July 2009 11.02 BST > > A coral seen off Jarvis Island in the Pacific Ocean. Photograph: Jim > Maragos/AP > > > David Attenborough joined scientists yesterday to warn that carbon dioxide > in the atmosphere is already above the level which condemns coral reefs to > extinction in the future, with catastrophic effects for the oceans and the > people who depend upon them. > > > Coral reefs support a quarter of all marine life including more than 4,000 > species of fish. They also provide spawning, nursery, refuge and feeding > areas for creatures such as lobsters, crabs, starfish and sea turtles. This > makes them crucial in supporting a healthy marine ecosystem upon which more > than 1bn people depend for food. Reefs also play a crucial role as natural > breakwaters, protecting coastlines from storms. > > > Attenborough said the world had a "moral responsibility" to save corals. > > > He was speaking yesterday at the Royal Society in London, following a > meeting of marine biologists. At the current rate of increase of atmospheric > CO2, they said, coral would become extinct within a few decades. > > > "A coral reef is the canary in the cage as far as the oceans are concerned," > said Attenborough. "They are the places where the damage is most easily and > quickly seen. It is more difficult for us to see what is happening in, for > example, the deep ocean or the central expanses of ocean." > > > "Anybody's who's had the privilege of diving on a coral reef will have seen > the natural world at its most glorious, diverse and beautiful," said > Attenborough. "[There is a] moral responsibility one has to the natural > world. Also you have responsibility to future generations, to your future > grandchildren and great grandchildren." > > > Increasing carbon dioxide in the atmosphere has a double effect on coral. > Global warming means warmer seas, which causes the corals to to bleach, > where the creatures lose the symbiotic algae they need to survive. Carbon > dioxide also makes seas more acidic, which means the corals find it > difficult to prevent their exoskeletons from dissolving. > > > "We've already passed a safe threshold for coral reef ecosystems in terms of > climate change. We believe that a safe level for CO2 is below 350 parts per > million," said Alex Rogers of the Zoological Society of London and > International Programme on the State of the Ocean, who helped organise > yesterday's meeting. > > > Carbon dioxide in the atmosphere has risen from 280 ppm before the > industrial revolution to around 387ppm today. Environmentalists say that any > new global deal on climate must restrict the growth of CO2 levels to 450ppm, > though more pessimistic scientists say that the world is heading for 550ppm > or even 650ppm. > > > "When we get up to and above 450ppm, that really means we're into the realms > of catastrophic destruction of coral reefs and we'll be moving into a > planetary-wide global extinction," said Rogers. > > > "The only way to get to 350ppm or below is not only to have major cuts in > CO2 emissions but also to draw CO2 out of the atmosphere through measures > such as geo-engineering." > > > Attenborough said the plight of the corals was another example of why the > control of carbon was so important to the world's inhabitants. "Each > ecological disaster or problem traces its cause back to carbon. To quibble > about this is really fiddling while Rome burns. If we do not control the > emission of carbon, this world is heading for a major catastrophe and this > is one of the first to be staring us straight in the face." > > ----- Original Message ----- > From: "DW" <[email protected]> > To: "geoengineering" <[email protected]> > Sent: Friday, July 17, 2009 6:54 PM > Subject: [geo] Re: david attenborough > > > > Can we get a link or a scan of the article? > > Dan > > On Jul 17, 12:13 pm, "John Gorman" <[email protected]> wrote: > >> from the widely read UK weekly The Week a quote from Sir David >> Attenborough >> >> "we're going to have to use geoengineering techniques" !!!! >> >> JOhn G >> --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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