根據研究報告，10-15%海洋受氣候變遷影響甚鉅，遠超過先前估計；而且受影響的區域正是「全球重要漁場」，包括當前最有經濟價值漁場的7.5%。聯合國緊急應變小組為此提出另一份報告，名為《 死水之中》(In Dead Wate)，首次具體揭示這些環境危害因子對海洋造成的多重衝擊。
Climate change is threatening the world's fish populations, already stressed by pollution, alien infestations and over-exploitation, warns a new report by the United Nations Environment Programme, UNEP.
The worst impacts are concentrated in 10 to 15 percent of the oceans, a far greater area than previously believed. These locations are "concurrent with today's most important fishing grounds," the report documents, including the 7.5 percent of the oceans that are the most economically valuable fishing areas of the world.
The findings come in a rapid response report entitled "In Dead Water," which for the first time maps the multiple impacts of these stressors on the seas and oceans.
The work of UNEP scientists in collaboration with universities and institutes in Europe and the United States, the report was presented today during the final day of UNEP's Governing Council/Global Ministerial Environment Forum in Monaco.
Dr. Christian Nellemann, head of the rapid response team that compiled the report, said, "We are already seeing evidence from a number of studies that increasing sea temperatures are causing changes in the distribution of marine life."
Some of these ocean changes are documented in the Continuous Plankton Recorder survey of the Northeast Atlantic. Warmer water species of tiny animals called copepods have moved northward by around 1,000 kilometers during the second half of the 20th century, with the patterns continuing into the 21st century, the survey shows.
The report shows that at least 75 percent of the world's key fishing grounds may be affected by changes in the circulation of ocean water as climate change interferes with the ocean's natural pumping systems. These natural pumps bring nutrients to fisheries and keep them healthy by flushing out wastes and pollution.
Higher sea surface temperatures over the coming decades also threaten to bleach and kill up to 80 percent of the world's coral reefs.
There also is growing concern that the atmospheric concentration of carbon dioxide, CO2, is steadily rising, and oceans directly assimilate CO2. As ocean concentration of CO2 increases, the oceans automatically become more acidic.
Dead zones, ocean areas low in oxygen, are increasing as a result of pollution from urban and agriculture areas. There are an estimated 200 temporary or permanent dead zones up from around 150 in 2003, the UNEP report shows.
In addition to the climate stress, fishing pressure is relentless. Up to 80 percent of the world's primary fish catch species are exploited beyond or close to their harvesting capacity, according to the report. Advances in technology, alongside subsidies, means the world's fishing capacity is 2.5 times bigger than that needed to sustainably harvest fisheries.
"Climate change threatens coastal infrastructure, food and water supplies and the health of people across the world," said UNEP Executive Director Achim Steiner. "It is clear from this report and others that it will add significantly to pressures on fish stocks." "This is as much a development and economic issue as it is an environmental one," he said. "Millions of people, including many in developing countries, derive their livelihoods from fishing, while around 2.6 billion people get their protein from seafood."
The report, "In Dead Water: Merging of climate change with pollution, over-harvest, and infestations in the world's fishing grounds," is online at: www.unep.org