Experts are beginning to wonder if we haven’t already exceeded the tipping point for life in the coral reefs. It is actually possible that living generations will never again experience the abundant coral reefs of only 50 years ago.
Professor Peter F. Sale from the University of Windsor, Canada, says that global warming may extinguish the world’s coral reefs—even if December’s UN climate change talks in Paris (COP21) result in a “wildly successful” universal treaty. From Professor Sale:
Even if Paris is wildly successful, and a treaty is struck, ocean warming and ocean acidification are going to continue beyond the end of this century. This is now serious; I find it very unlikely that coral reefs, as I knew them in the mid-1960s, will still be found anywhere on this planet by mid-century. Instead, we will have algal-dominated, rubble-strewn, slowly eroding limestone benches.
I see little hope for reefs unless we embark on a more aggressive emissions reduction plan. Aiming for CO2 at 350 ppm, or a total warming of around 1 degree C, is scientifically defendable, and would give reefs a good chance. A number of coral reef scientists have called for this.
Professor Sale made the remarks during a recent plenary presentation at the respected Goldschmidt geochemistry conference in Prague. He noted that “At present, world leaders hope to reach climate change agreements that will lead to global temperatures increasing by no more than 2C by the end of the century.” According to Sale and others in the reef science field, two degrees just won’t cut it for these undersea ecosystems.
Sale is even talking about the Great Barrier Reef, the world’s largest oceanic ecosystem, which comprises over 2,900 individual reefs and 900 islands and cuts a 1,400 mile (2,300 km) swath through the Coral Sea off the coast of Queensland, Australia. Scientists from the Carnegie Institution in Washington DC said last year that coral growth rates in the Great Barrier Reef—largest coral structure in the world—have fallen by 40% since the 1970s.
They attribute most of this loss to the ocean acidifying because it has had to absorb much more atmospheric carbon dioxide recently than it did just 200 years ago. Seawater becomes more acidic due to chemical reactions with CO2 that interfere with and reduce seawater pH, carbonate ion concentration, and biologically important calcium carbonate mineral saturation. These impacts may result in marine life migrating deeper.
Says Dr. Jonny Start, the Antarctic study’s diver and chief investigator:
It’s only a 0.4pH change, but it is actually a very big change in pH and would have very serious implications for a lot of marine life. For example, it can affect everything from the reproduction, to the growth and development of many marine organisms.
Access the team’s video here or just watch it right here:
An even more recent study from Germany’s Potsdam Institute for Climate Impact Research calculated how long it will take to reverse this amount of industrial (anthropomorphic) ocean acidification. The result, even with aggressive CO2 removal techniques? More than seven centuries— three and a half times the industrial era that caused it.
Previous scientific analyses posited that coral reefs could bounce back from severe environmental impact. An exploration by Australian divers in the Antarctic measured acidification measured for first time and found that the photosynthesis of some marine plants apparently changed in response to more acidic seawater (see photo).
- We have lost 90% of our commercial fish biomass since the 1940s.
- We are polluting coastal waters.
- The great majority of marine protected areas are not being protected.
Effects of climate change on the world’s oceans, which cover about two-thirds of earth’s surface, have not been historically top of mind in recent environmental research reports, which have concentrated instead on direct effects to human life, worsening weather, and mitigation and adaptation on land. Either the nations of the world abandon the policy of freedom on “the high seas” and agree on some limits, as Hannah Osborne points out in her recent article in the International Business Times, or humans will bear the responsibility of the death of large parts of the oceans.
Says John Veron, former chief scientist of the Australian Institute of Marine Science:
Only drastic action starting now will prevent wholesale destruction of reefs and other similarly affected ecosystems. Should humanity not be successful in preventing these threats from becoming reality, no amount of management or expenditure will save future generations from the consequences of our failed guardianship.
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