terça-feira, 10 de junho de 2008

Disasters are often used to illustrate the range of potential effects of global warming. Hurricane Katrina and the devastation it caused in the Gulf region in 2005 and the 2003 European heat
wave that caused 35,000 deaths and $15 billion in agricultural damage are two of the more commonly cited examples. Yet the impact of climate change on human and global security could extend far beyond the limited scope the world has seen thus far.

The Intergovernmental Panel on Climate Change (IPCC) examined the impacts of climate change on natural and social systems in Working Group II of its 2007 assessment report and concluded that climate change will affect species and ecosystems in all parts of the world—such as rainforests, coral reefs, and Arctic ecosystems—and that some already show stress symptoms. [1]

Due to climate change, the total area stricken with drought will likely increase, and water supplies stored in glaciers and snow cover in major mountain ranges such as the Andes and Himalayas will likely decline, jeopardizing access to water in large regions. Where natural
resources are already in a critical stage, global warming will tend to further degrade the environment as a source or sink of these resources. By degrading the natural resource base,
climate change will increase the environmental stress on the world’s population.

A combination of these stress factors could lead to cascading effects. Some of the environmental changes may directly threaten human health and life, such as floods, storms, droughts, and heat waves. Others, such as food and water scarcity, disease, and weakened economic and ecological
systems, could gradually undermine human well-being.

Environmental changes caused by global warming will not only affect human living conditions but may also generate larger societal effects, by threatening the infrastructures of society or by
inducing social responses that aggravate the problem. The associated socio-economic and political stress can undermine the functioning of communities, the effectiveness of institutions, and the stability of societal structures. These degraded conditions could contribute to civil strife and, worse, armed conflict.

According to the IPCC, confining the impacts will be difficult: “Where extreme weather events become more intense and/or more frequent, the economic and social costs of those events will increase.”

Whether societies are able to cope with the impacts and restrain the risks depends on their vulnerability, which the IPCC defines as a function of the “character, magnitude, and rate of climate change and variation to which a system is exposed, its sensitivity, and its adaptive capacity.” Societies that depend more on an ecosystem’s services and agriculture tend to be more vulnerable to climate stress. Some regions such as Bangladesh and the African Sahel are
more vulnerable due to their geographic and socioeconomic conditions and lack of adaptive capacities. Countries and communities that are not affected initially may become vulnerable later. Due to nonlinear effects, an increase in global mean temperature above a certain
threshold, say 2 degrees Celsius, may result in disproportionate impacts. [2]

The stronger the impact and the larger the affected region, the more challenging it becomes for societies to absorb the consequences. Large-scale and abrupt changes in the Earth system, beyond so-called “tipping points,” could have incalculable consequences on a continental and global scale. [3]

The societal implications of climate change crucially depend on how human beings, social systems, and political institutions respond. Some measures facilitate adaptation and minimize the risks, others may cause more problems. For instance, populations could respond to environmental hardships by migrating, which would spread potential hotspots of social unrest.[4]

These developments could turn into security problems, as the 2006 Stern Review on the Economics of Climate Change acknowledges: “Climate-related shocks have sparked violent conflict in the past, and conflict is a serious risk in areas such as West Africa, the Nile Basin, and Central Asia.”

Climate change and security

How is global warming affecting existing competition for resources and changing international security priorities? A survey of recent research shows how complex the picture could become.
By Jürgen Scheffran

Link to pdf file: http://thebulletin.metapress.com/content/926l0jg36j374838/fulltext.pdf

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