New Delhi (ISJ) - Ocean warming may well turn out to be the greatest hidden challenge of our generation. More than 93% of the enhanced heating since the 1970s, resulting from human activities has been absorbed by the ocean. A new report by the International Union for Conservation of Nature, IUCN indicates there is a sustained and accelerating upward trend in ocean warming. The scale of ocean warming depicted in the report is truly staggering -� if the same amount of heat that has gone into the top 2 km of the ocean between 1955 and 2010 had instead gone into the lower 10 km of the atmosphere, the Earth would have seen a warming of 36�C.
Compiled for IUCN by 80 scientists in 12 countries, the report explores the impacts of ocean warming on ecosystems and species, and on the every-day benefits derived from the ocean ? its ?goods and services?.
?Ocean warming has led to increased rainfall in mid-latitudes and monsoon areas, and less rain in various sub-tropical regions. These changes will have impacts on crop yields in important food-producing regions such as North America and India,? suggests the report.
Warming oceans are affecting fish stocks in some areas by damaging fish habitats, forcing them to move to cooler waters. This would result in reduced catches in tropical regions, like India, says the report.
In East Africa and the Western Indian Ocean, for example, ocean warming has reduced the abundance of some fish species by killing parts of the coral reefs they depend on, adding to losses caused by overfishing and destructive fishing techniques. In South-East Asia, harvests from marine fisheries are expected to fall by between 10% and 30% by 2050 relative to 1970-2000, as the distributions of fish species shift, under a high ?business as usual? greenhouse gas emission scenario, the report states.
The report also highlights evidence that ocean warming is causing increased disease in plant and animal populations, and impacting human health as pathogens spread more easily in warmer waters, including cholera-bearing bacteria and harmful algal blooms that cause neurological diseases like ciguatera.
Warming oceans are also affecting the weather, with a range of knock-on effects on humans. The number of severe hurricanes has increased at a rate of around 25-30% per degree of global warming, the report states.
The protection against climate change offered to us by oceans and their ecosystems ? such as absorbing large amounts of CO2 and sheltering us from storms and erosion ? is also likely to reduce as the ocean warms, according to the report.
The report?s recommendations include recognising the severity of ocean warming impacts on ocean ecosystems and the benefits they provide to humans, expanding marine protected areas, introducing legal protection for the high seas, better evaluating the social and economic risks associated with warming oceans and continuing to fill gaps in scientific knowledge, as well as cutting greenhouse gas emissions rapidly and substantially.
The report also describes the inadequacy of current knowledge, capabilities and capacity to adequately study ocean warming, and to advise and cope with the associated challenges.
The report is being launched at the IUCN World Conservation Congress, a key moment to press home the urgency with which such reductions now need to be achieved.
Source: IUCN Report
Image courtesy: IUCN