Rising CO2 levels acidifying oceans, threatening sea life
According to an international group of scientists, carbon-dioxide emissions are threatening marine life and human food supplies by making the oceans more acidic.
More than 150 leading marine scientists are calling for immediate action to reduce CO2 emissions sharply so as to avoid widespread and severe damage to marine ecosystems from increasing ocean acidification—the “other CO2 problem”. They issued this warning in the Monaco Declaration, released on 30 January, 2009.
The surface ocean currently absorbs about one-fourth of the carbon dioxide emitted to the atmosphere (more than 20 million tons per day) from human activities, namely from fossil-fuel combustion, deforestation, and cement production. However, when CO2 dissolves in seawater, it forms carbonic acid. That increases the acidity of seawater, making it easier for the water to dissolve the shells of corals and shellfish. This ongoing ocean acidification also reduces the ability of many marine organisms to build their shells and skeletal structure. Increasing acidity and related changes in seawater chemistry also affect reproduction, behaviour, and general physiological functions of some marine organisms.
The scientists note that ocean acidification is accelerating. They caution that its negative socio-economic impacts could destroy coral reefs, threaten the fishing and tourism industries and affect the food supplies of millions of people unless policymakers work to curb carbon dioxide levels, the declaration said.
Measurements show that the acidity at the surface of the ocean has increased by 30 per cent since industrialization began in the 18th century. Scientists predict that if nothing is done to reduce CO2 emissions, most of the world’s oceans could be inhospitable to coral reefs by the middle of this century. The reefs currently provide important fish habitat and protect coastal areas from flooding. The rising acidity could also make it more difficult for the oceans to absorb additional carbon dioxide, thus exacerbating climate change.
For more information on this important topic, please visit The Ocean Acidification Network.
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