Marine: Cleaner Seas report
Inputs from land
Atmospheric effects
Global climate is expected to continue to change throughout the next century as a result of human activities. The size of the change will depend on the extent by which greenhouse gas emissions are reduced. Global temperatures are approximately 0.6oC higher than they were at the end of the last century and are predicted, by the Intergovernmental Panel on Climate Change (IPCC), to increase by a further 2oC by 2100.Global sea level has risen between 10 and 25 cm over the last 100 years. Projections of future changes estimate that sea level will be approximately 50 cm higher than it is today by the year 2100. Most of this rise is expected from thermal expansion of water, together with increased melting of land ice. Importantly, sea levels respond to warming over a long time-scale, and even if climate change is halted, levels will continue to rise for centuries afterwards. Sea level rise on this scale could put many low lying coastal areas at risk, threatening urban areas, agriculture, fisheries, industry and natural wetlands and other habitats. Low lying small islands are particularly threatened and measures to combat sea level rise will be costly.
Sea level rise will also significantly increase flood risk, resulting in more frequent and damaging flooding in coastal towns and harbours. Further-more, it could adversely affect ground water supply, and thereby affect human health. Changes in sea surface temperature will cause geographical shifts in the range of marine biota as well as changes in biodiversity. Changes in ocean circulation would influence nutrient availability and primary productivity and may reduce fish stocks. It will also affect the oceans uptake and storage capacity for greenhouse gases and could have significant impacts on regional climate.
The 3rd meeting of the UN Framework Convention on Climate Change held in Kyoto in December 1997 agreed targets to limit the increase in developed countries' greenhouse gas emissions by 5% by 2010. However, this is only a first step on a long road to halt the rise in greenhouse gas emissions in the atmosphere, their impact on global warming and potential threats to the marine environment.
Page last modified:
01 March 2005
Page published: 21 September 1988