Security

The Military Boars, a panel of retired U.S. generals and admirals released a report en titled "National Security and the Threat of Climate Change. " The report prdicts that global warming will have security implication, in particular serving as a "threat multiplier" in already volatile regions. Britain's Foreing Secretary Margaret Beckett argues that "An unstable climate will exacerbate some of the core drivers of conflic, such as migratory pressures and competition for resources.

Economic and Social

Indigenous populations in high-latitude areas are already experiencing significant adverse impacts because of climate change. The impact of future climate change on system will likely be unevenly distributed. Africa is probably the most vulnerable continent to future climate change. Developing countries are problably more vulnerable to climate change than developed countries. With warming of 1-2 ºC above 1990-2000 levelsm it is likely that key negative impacts would be experienced in some regions.

Shutdonwn of Thermohaline Circulation

There is some speculation that global warming could, via a shutdown or slowdown of the thermohaline ciculation, trigger localized cooling in the North Atlantic and lead to cooling, or lesser warming, in the region. This would affect in particular areas like Scandinavia and Britain that are warmed by the North Atlantic drift.

Acidification

Ocean acidification is an effect of rising concentration of CO2 in the atmosphere, and is not a direct consequence of global warming. The oceas soak up much of the CO2 produced by living oranisms, either as dissolved gas, or in the skeleton of tiny marine creatures that fall to the bottom to become chalk or limestone

Temperature rise

From 1961 to 2003, the global oceans temperature has rise by 0. 10 ºC from the surface to a depth of 700 m. There is variabiliti both year-to-year and over longer time scale, with global ocena heat content observations showing high ates of warming for 1991 to 2003, but some cooling from 2003 to 2007. The temperature of the antartic southerm Ocean rose by 0.17 ºC (0.31 ºF) between the 1950s and the 1980s, nealy twicw the ratw for the world's oceans as a whole.

Oceans

The role of the oceans in global warmingis a complex one. the oceans serve as a sink for carbon dioxide, taking up much that would otherwise remian in the armosphere, but increased levels, of CO2 have led to ocean ocidification. furthermore, as the temprerature of the oceans increases. they become less able to absorb excess CO2. Global warming is projected to have a number of effect on the oceans. Ongoing effects incluide rising sea levels fue to thermal expansion and melting of glaciers and ise sheets, and warming of the ocean surface, leading to increased temperature stratification.


The Melting of Glaciers




















In historic times, glaciers grew during a cool period from about 1550 to 1850 know as the little Ice Age. Subsequently, until about 1940, glaciers around the world retreated as the climate warmed. Glacier retreat declined and reversed in many cases from 1950 to the existences of many of the glaciers of the world. this process has increased markedly since 1995.

Excluding the ice caps and ice sheets of the Arctic and Antartic. the total surface area of glaciers worldwide has decreased by 50% since the end of the 19th century.

The lost of glaciers not only directly causes landslides, flash floods end glacial lake overflow, but also increases annual variation in water flows in rivers.