This weekend has seen two important pieces of news released on Saturday, 11 December 2010, both having an impact on the marine environment, and, in time, on the reef aquarium hobby.
2010 Meteorological Year Warmest on Record.
Firstly, NASA reported that the 2010 meteorological year, which ended on 30 November, was the warmest in NASA’s 130-year record, Over the oceans as well as on land, the average global temperature for the 12-month period that began last December was 14.65˚C. That’s 0.65˚C warmer than the average global temperature between 1951 and 1980, a period scientists use as a basis for comparison.
The 2010 meteorological year was slightly warmer than the previous warmest year, the 2005 calendar year, when the average temperature was 14.53˚C.
In 2010, temperatures measured over land alone were also the warmest ever, with instruments showing a December-November average of 14.85˚C. Combining this warming with above-average ocean temperatures led to the global average of 14.65˚C.
Cancun Climate Talks Acknowledges Temperature Rise Needs to be Limited to 2˚ C
Secondly, the UN climate talks in Cancun, Mexico, have concluded with an agreement that acknowledges the need to keep temperature rises to 2C and brings non-binding emissions cuts pledges made under the voluntary Copenhagen Accord, into the UN process.
It also includes an agreement to set up a green climate fund as part of efforts to deliver 100 billion US dollars (£60 billion) a year by 2020 to poor countries to help them cope with the impacts of global warming and develop without polluting. The proposed deal does not include a commitment to extend Kyoto beyond 2012, when it is due to expire, but it would prevent a collapse of climate change negotiations
More than 190 countries have struck an agreement at the latest round of UN climate talks that puts efforts to secure a new international deal to tackle global warming back on track. Representatives from the various countries acknowledged the agreement was not perfect, but that they supported it as progress towards a final goal.
Environmental campaigners said it threw a lifeline to efforts to get a deal to tackle climate change but there was still much work to do, in particular to close the “gigatonne gap” between the greenhouse emissions cuts countries have pledged and the reductions needed to limit temperature rises to no more than 2C.
Cancun may have saved the process but it has not yet saved the climate; with each year that passes without a globally binding agreement to cut emissions and finance poor countries’ needs to adapt to climate change and develop low-carbon economies, the impacts will become more and more severe.
This is the first time that the need for emissions to peak and decline as soon as possible has been recognised, with the target of staying within a 2C temperature rise and with an ongoing assessment of whether the level of emissions cuts needs to be higher.
But What About the Reefs?
While this holds out promise for the good of mankind, it will be of no help to the reefs.
The goal of limit global warming to 2 degrees C is too little too late, says coral expert Roberto Iglesias. “That represents the end of the coral reefs in the world,” says the Mexican scientist, who works at a marine research station in Puerto Morelos, about 20 kilometres south of Cancun.
Coral reefs host 25 percent of marine species and provide food and income to hundreds of millions of people, mostly in the developing world. They also serve as coastal protection to storm surges whipped up by hurricanes, typhoons, and Tsunamis.
Many reefs around the world have been damaged by water pollution and over fishing, leaving them vulnerable to a warming ocean that “bleaches” corals and sometimes kills them, Iglesias said.
This year, preliminary reports show global coral bleaching reached its worst level since 1998, when 16 percent of the world’s reefs were killed off, said Mark Eakin, a coral reef specialist at the U.S. National Oceanic and Atmospheric Administration (NOAA). “Clearly, we are on track for this to be the second worst bleaching on record,” he said. “All we’re waiting on now is the body count.”
The 1,100-kilometer reef that runs along Mexico’s Yucatan Peninsula although suffering other stresses, has been spared bleaching this year, but other parts of the Caribbean have been hit hard, including Tobago, Curacao, Panama and islands north of Venezuela. Worldwide, some of the biggest impacts were in Southeast Asia. In Indonesia’s Aceh province, surveys showed some 80 percent of the bleached corals died. In July, Malaysia closed several popular dive sites after bleaching damaged virtually all the corals in those areas. (For more, see: Global Bleaching 2010)
Bleaching occurs when warmer temperatures disturb the symbiotic relationship between the corals and the zooxanthellae, a kind of algae, living inside them. When stressed, corals expel the algae and appear white, the colour of their skeleton. Just1 or 2 degrees C above normal can be enough to cause bleaching. Corals can recover if the water returns to normal temperature and they can recruit new algae, but they’re still significantly weaker and more vulnerable to disease. If the warmer temperatures persist, the corals die.
Bleaching occurs due to natural temperature variation; both the 1998 and 2010 events were linked to the El Nino weather phenomenon. But the gradual rise of ocean temperatures means it won’t take much to push them over the edge,” Eakin said.
The World Meteorological Organization says most tropical waters already have seen surface temperatures rise by up to 0.5 C in the past 50 years. The Intergovernmental Panel on Climate Change, the U.N. climate-science network, projects an increasing frequency of bleaching episodes that is very likely to further reduce both coral cover and diversity on reefs over the next few decades. Additionally many reefs have already been degraded by disease and the impact of human activities, including discharges of fertilizers and waste as well as over fishing of parrotfish and other species that help keep coral reefs healthy.
The global area covered by coral reefs has shrunk by 20 percent since 1950 and another 35 percent could disappear in the next 40 years, even without the impact of climate change, according to a report released in October by the World Meteorological Organization and the Convention on Biological Diversity.
Off the Riviera Maya coast south of Cancun, where large swaths of mangrove forests have been cut down to make room for beachfront resorts, only 15 percent of the coral reefs are alive, down from about 45 percent in 1995, said Fernando Secaira, who coordinates a Mesoamerican Reef program for the U.S.-based environmental group Nature Conservancy. The biggest problem is the rapid development, with tens of thousands of hotel rooms being added over the past decade. Fertilizers from lawns and golf courses and sewage from the developments filters through the limestone rock and is washed out onto the reef by underground rivers, altering the balance of the sensitive ecosystem. Secaira said such unhealthy reefs would find it difficult to adjust to warming waters, raising the risk they will be destroyed by bleaching or diseases. The priority for conservationists is identifying the most resilient reefs, and protecting them as climate change sets in with full force, raising temperatures and acidifying the ocean, which limits the carbonate minerals that help corals grow.
Scientists say no emissions cuts being considered by world governments will suffice to prevent that from happening. “We’re going to lose more corals and more reefs before this is all over,” said Eakin, of NOAA. “The question at this point is how many can we save.
What Does the Future Hold for the Reefs?
There is hope that some areas of reefs will survive with little in the way of losses, typically these are reefs which are already subject to wide temperature variation but although they may remain resilient to bleaching this does not take into account acidification.
There will always be reefs but they will not be the same as the reefs that we are familiar with. Expect the loss of SPS species such as Acropora, Montipora, Pocillopora, and the other similar corals. This will be one of the biggest problems to face the fisheries, as with the loss off coral cover, so we lose the environment required by many ornamental and food fish species.
Expect to lose the other stony coral species, although there is speculation that some species may adapt by abandoning skeleton building in favour of developing into new soft bodied species. Some coral scientists believe this is what happened in the past with corallimorpharians or mushroom corals.
Soft corals may survive with varying degrees of success, not being as reliant on the process of calcification as stony corals – yet it is important to remember that many soft coral do calcify, producing calcium spicules or sclerites, needle like calcium structures, which can be involved in supporting the body of the coral or as protection against predation.
Anemones may well survive, but probably only if there is an increase in available food to make up for the loss of zooxanthellae – the host anemones we associate with clownfishes are all photosynthetic and are subject to the same bleaching mechanism as corals.
To be continued (unfortunately) …