Wednesday, 2 September 2009
By Richard Black, Environment correspondent, BBC News
Coral reefs do more than look pretty – they are nurseries for many fish
[Carnegie Institution’s Department of Global Ecology says that by 2050, 98 percent of today’s coral reefs will be in waters too acidic to support their growth.]
Current climate targets are not enough to save the world’s coral reefs – and policymakers urgently need to consider the economic consequences.
Studies suggest that reefs are worth more than $100bn (£60bn) annually, but are already being damaged by rising temperatures and more acidic oceans.
TEEB’s analysis suggests that between half a billion and one billion people depend on coral reefs for at least part of their food supply.Damage to the Great Barrier Reef could also have an impact on a tourism market worth A$5 billion a year, he added.
Mr Sukhdev, who is on secondment to the UN Environment Programme (Unep) from the global markets division of Deutsche Bank, cited studies showing that money spent on nature preservation provided rates of return of between three and 75 times the initial investment.
Preserving forests kept fresh water systems intact, he noted. Coral reefs and mangroves protected communities from storm damage; and healthy ecosystems were essential for food production.
Green roots
The current UN climate negotiations contain measures for protecting forests as carbon stores – keeping CO2 out of the atmosphere and oceans – an initiative called Redd (Reducing Emissions from Deforestation and forest Degradation).
Its roots lie in the calculation that forest loss accounts for about 20% of greenhouse gas emissions, and that combating it is probably the cheapest way of reducing emissions overall.
[A UK Meteorological Office study concluded there would be a 75% loss of tree cover if the world warmed by three degrees for a century.]
But protecting societies against climate impacts (financing climate adaptation) will also be a key component of any Copenhagen deal, because it is the single biggest priority for many developing nations.
The TEEB (The Economics of Ecosystems and Biodiversity) analysis emphasises that forests, coral reefs and many other ecosystems can be the cheapest “adaptation tools” as well.
“We feel this isn’t really at the top of politicians’ minds at the moment,” he told BBC News.
“But when you decide how you invest money for climate adaptation, you quickly come to the conclusion that ecology provides the best bangs for bucks – and that’s even without taking into account the added benefits of saving biodiversity.”
There are a number of somewhat notional targets on the table in the run-up to Copenhagen.
One, an EU initiative that now has much wider support, is to keep the global average temperature rise since the pre-industrial age within 2C – which according to some analyses means carbon dioxide concentrations in the atmosphere cannot rise above 450 parts per million (ppm).
The current level is about 387ppm, and it is rising at about 2ppm each year, although this year’s global recession may bring a blip.
Mr Sukhdev’s team heard evidence from coral scientists that these targets would not be enough to prevent damage to coral reefs around the tropics.
“There’s evidence that current levels of CO2 are already causing damage to reefs,” said Alex Rogers from London’s Institute of Zoology.
“Stabilising at anything more than about 350ppm will lead to further destruction, and really we need to be aiming for zero emissions.”
Elevated carbon dioxide levels in the atmosphere have a twin impact on coral. They warm the oceans; but also, a portion of the extra CO2 becomes dissolved in seawater, which makes it slightly more acidic (or less alkali).
Ocean pH levels have already decreased by about 0.1 since pre-industrial times.
A 2007 study showed that rates of coral growth on the Great Barrier Reef had fallen by 14% since 1990.
Set up in 2007 by the German government and the European Commission, TEEB is now supported by some other governments (including the UK) and by Unep.
Its final report is due out in the second half of 2010, just before a key meeting of the UN biodiversity convention.
For that analysis, Mr Sukhdev’s team will also attempt to capture the economics of fisheries loss, and finalise a complex matrix giving legislators comprehensive information about the costs and benefits of protecting – or destroying – various aspects of the natural world.
Richard.Black-INTERNET@bbc.co.uk
Coral reefs suffer unprecented levels of damage
06-20-2006, SYDNEY, AFP Cosmos
Coral reefs have suffered more damage since the 1970s than any time in the last 220,000 years
Australian scientists found that coral reefs in the Caribbean island of Barbados were unchanged over tens of thousands of years, despite rising and falling sea levels.
But according to the paper published in the science journal Ecology Letters, modern day reefs are now startlingly different and dominated by different species of coral.
Associate Professor John Pandolfi, of the Australian Research Council’s Centre of Excellence for Coral Reef Studies, said that human activity had made reefs far more susceptible to change.
“Our biggest fear is that humans have pushed them to a completely different state where they are far more vulnerable to change than ever before. We have to be on guard,” said Pandolfi, who led the study.
“There is evidence of very dramatic difference over the last 30 years,” he said.
Pandolfi studied the preserved remains of entire coral reef communities that lived in the Caribbean up to 220,000 years ago.
He analyzed four periods in the reef’s history, when geological activity pushed it to the surface and wiped out the coral community.
Each time, the sea floor was recolonised and the coral reef returned in a very similar structure with the same species.
But since the 1970s the Elkhorn coral that once dominated the reef has virtually disappeared and algae and seaweed have taken over, he said.
Overfishing was partly to blame, as there were no longer enough large fish and turtles to eat the algae.
Coastal development – such as destroying forests for sugar cane plantations and other agriculture – had also impacted on the reef as increased levels of nutrients in the water favoured the algae, he added.
“This study is a warning bell that if Australia is not proactive in its coral reef management we will see similar changes in the Great Barrier Reef,” Pandolfi said.
“If our reefs are going to survive the impacts of climate change, they have to be at the peak of their health.”
Coral reefs have been experiencing a global decline that scientists attribute to a combination of pollution, destructive fishing and global warming. A feature story on page 32 of issue 9 of Cosmos details the perils facing the Great Barrier Reef.
One of the worst dangers is bleaching, caused when the plant-like organisms which make up coral die and leave behind the white limestone skeleton on the reef.
A rise in coral bleaching has been linked to global warming, but scientists are still trying to fully understand the phenomenon.
Pandolfi said that damage to coral reefs would have an impact on nations that depend on them for food and the natural protection they offer from storms.
Damage to the Great Barrier Reef could also have an impact on a tourism market worth A$5 billion a year, he added.
Stretching over more than 345,000 square kilometres off Queensland’s coast, the reef is the world’s biggest coral system and the marine park there has been listed by the United Nations as a World Heritage site.
The centre of excellence is a partnership between Australia’s James Cook University, the Australian Institute of Marine Science, The Australian National University, the Great Barrier Reef Marine Park Authority (GBRMPA) and The University of Queensland.