A change in the distribution of fish population that has resulted because of ocean warming, oxygen loss, nutrient supply changes and acidification has led to the reduction of global catch, according to a special report of the latest Intergovernmental Panel on Climate Change.
The report on Ocean and Cryosphere in a Changing Climate points out that marine life in the sea floor and Open Ocean has been widely affected.
With respect to warming, the report says that ocean has absorbed more than 90 per cent of excess heat. As ocean warming increases, it reduces oxygen and nutrient supply for marine life.
The report says that since 1982, marine heat waves have increased in frequency. It also said that heat wave is likely to increase in frequency and intensity. At 2 degree centigrade, heat wave frequency would be twenty times when compared to pre-industrial levels. If emission continued in this level, the heat wave would occur 50 times more. The report also states that acidification would increase once carbon uptake by ocean goes in this level.
The latest Intergovernmental Panel on Climate Change also maintains that sea level would only increase in the coming years. By 2100, it was expected to reach about 30 to 60 cm if green house emission is reduced below two degrees. However, if the emission is not reduced, then the sea level would have a rise of 60 to 110 cm.
With ice sheets and Glaciers in mountains and Polar Regions losing mass, the report said that the rising rate of sea level will be even worse. Stating that sea level has risen by 15 cm in 20th century, the report said that the level is rising at an accelerated with approximately 3.6 mm per year. In the report, it has been said that a few island nations would become uninhabitable because of cryosphere changes. The report warns that there would be an increase in coastal hazards, tropical cyclone winds.