Ocean warming
From Envirowiki
With the heavy emissions of Greenhouse gases that are entering the Earth’s atmosphere, a topic of great urgency is how the change in the climate will affect the ocean’s temperature. This topic has already gained notice from the public with the help of drowning polar bears and miles of ice sheets breaking off, however the problem is even more intricate than that.
Marine organisms need very specific conditions in order to survive in their environment. When the temperature changed even a little the entire ecosystem could be drastically affected. Take the case of coral reefs in the Caribbean. Just the slightest temperature increase could act as a stressor on the corals themselves as well as the organisms that inhabit the reef. This fragile ecosystem could crumble in a very short time.
What is also disconcerting is the potential for the sea level to rise globally. It has been predicted that the sea level will have risen by half a meter in most places around the world by 2100! This will impact the global coastlines in a way never before seen. Erosion will occur that will drastically change beaches and coastal development. Floods will occur more frequently in low lying area. Salt water could potentially infiltrate freshwater reservoirs that would stress the freshwater supply even more so.
There are two main theories that scientists have as to how this change will occur. The most obvious theory is that the Antarctic, Greenland and other polar ice sheets will begin melting. If the Antarctic ice sheet were to melt completely the sea level would rise by over 60 meters[1]! It has already been estimated that over 13,000 sq km of sea ice in the Antarctic Peninsula has been lost over the last 50 years. Furthermore, over the past five years, studies have found that melting Antarctic ice caps contribute at least 15% to the current global sea level rise of 2mm (0.08in) a year. In 2001, the Intergovernmental Panel on Climate Change (IPCC) predicted the average global sea level would rise by between 11cm (4.3in) and 77cm (30.3in) by 2100 - but forecast that Antarctic's contribution would be small[2]. With these predictions it is difficult to even comprehend how the world will look one hundred years from now.
The other way that global sea levels will rise will be through the process of water volume to increase when heated. This theory of global thermal expansion states that when the water temperatures rise, the water in the oceans will actually expand causing the sea level to increase. Although this will not have as great an impact as the melting of the polar ice caps and sheet will, it is still an uncertainty that has been addressed by scientists.
The only way to stop this catastrophe from happening is to cut down on fossil fuel emissions that are heating our world’s atmosphere and consequently increasing surface water temperatures. There is no way to fully predict the extent to which this will affect human life and coastal habitats, however, with the help of global climate models, it is understood that the heat moves between the atmosphere and the ocean’s surfaces. So when ocean’s temperatures rise due to the increase in the temperature of the atmosphere, it will have a boomerang effect and influence the climate to change even more drastically.
[edit] References
- ↑ Salt, David. Getting into hot water- global warming and rising sea levels. March 2004. www.science.org.au/nova
- ↑ Antarctic’s ice ‘melting faster’. BBC News. February 2005. http://news.bbc.co.uk/go/pr/fr/-/1/hi/uk/4228411.stm
