Climate change devastates oceansBy Asia Sentinel Nov 03, 2010 5:49PM UTC
Even as warming seas trigger unprecedented species decline, policymakers avoid climate-change action, writes Asia Sentinel’s Alex David Rogers
Legislators, scientists and conservationists meet again in Nagoya, Japan, under the gathering clouds of species extinction to discuss the state of Earth’s biodiversity at the Tenth Conference of Parties for the Convention on Biological Diversity.
It takes place amidst discouraging news.
The convention’s Global Biodiversity Outlook 3 reports that the target, set in 2002, to achieve significant reduction in the rate of biodiversity loss by 2010 has failed. Underlying causes of continued loss of biodiversity include habitat loss, unsustainable use and overexploitation of biological resources, climate change, invasive species and pollution.
There is some good news in this report on localized or partial success in stemming some of these pressures. However, while climate change is viewed as a threat of “increasing significance,” it’s remarkable that this document does not call for international agreement on an effective course of action to tackle climate change with utmost urgency.
Without such an agreement, humankind will be the causative agent of a planetary extinction expected to rival the five great extinctions recorded in geological history.
Coral reefs are the most species-rich marine ecosystems on Earth. Despite only comprising about 0.2 percent of the area of the oceans, coral reefs host a quarter of all marine fish species and perhaps 1 to 3 million marine species in total. In economic terms, they provide goods and services estimated up to $375 billion per annum. Around 500 million to 1 billion people rely on coral reefs for food, and 30 million of the world’s poorest people in coastal communities depend entirely on reefs as their primary means of food production and livelihood.
The impacts of climate change are already apparent on coral reefs. There’s no need to resort to models that forecast the effects of increased global temperatures on coral-reef ecosystems and the species associated with them, the evidence is there. In the late 1970s the first mass coral-bleaching events were recorded. This phenomenon is associated with abnormally high sea-surface temperatures and results from the corals ejecting algal symbionts from their tissues.
The symbionts, microscopic plants, produce energy from photosynthesis and provide corals with most of their nutrients. Once these are ejected from coral tissues, the corals change from various shades of brown to a bleached white color; if warm conditions are prolonged, the corals die.