the war on the climate. http://www.cnn.com/2008/POLITICS/06/25/climate.change.security/index.html Report calls global warming a threat to U.S. security * Story Highlights * Climate change could destabilize weak states, U.S. report finds * It says free flow of commodities could be disrupted by climate change * Global warming could increase U.S. food production, report suggests * But experts say coasts could be threatened by larger storm surges * Next Article in Politics » Decrease font Decrease font Enlarge font Enlarge font WASHINGTON (CNN) -- Global warming's greatest threat to U.S. security will result from the way climate change destabilizes countries that are less able to handle its effects, according to a comprehensive government analysis of the subject. Climate change could increase flooding in coastal areas, like the flooding that hit the Philippines. Climate change could increase flooding in coastal areas, like the flooding that hit the Philippines. "Climate change alone is unlikely to trigger state failure in any state out to 2030, but the impacts will worsen existing problems -- such as poverty, social tensions, environmental degradation, ineffectual leadership and weak political institutions," Thomas Fingar, the chairman of the National Intelligence Council, told Congress on Wednesday. "Economic refugees will perceive additional reasons to flee their homes because of harsher climates," he predicted. That will put pressure on countries receiving refugees, many of which "will have neither the resources nor interest to host these climate migrants," he said in testimony to the House Select Committee on Energy Independence and Global Warming. Global warming may have a slight positive effect on the United States, since it is likely to produce larger farming yields, Fingar said But it is also likely to result in storm surges that could affect nuclear facilities and oil refineries near coasts, water shortages in the Southwest, and longer summers with more wildfires, the study found. International migration may also help spread disease, Fingar added. And climate change could put stress on international trade in essential commodities, he said. Don't Miss * In Depth: Planet in Peril * Scientist: 'We're toast' without action on climate * Obama slams McCain's energy policy "The United States depends on a smooth-functioning international system ensuring the flow of trade and market access to critical raw materials, such as oil and gas, and security for its allies and partners. Climate change and climate change policies could affect all of these," he warned, "with significant geopolitical consequences." Fingar painted a mixed picture of the effects of climate change on the United States itself. "Most studies suggest the United States as a whole will enjoy modest economic benefits over the next few decades, largely due to the increased crop yields," he said. "Costs begin to mount thereafter, however, and some parts of the United States -- particularly built-up coastal areas -- will be at greater risk of extreme weather events and potentially high costs related to losses in complex infrastructure." The impact of fighting and preparing for climate change may be greater than the effect of global warming itself, Fingar said. "Government, business and public efforts to develop mitigation and adaptation strategies to deal with climate change -- from policies to reduce greenhouse gases to plans to reduce exposure to climate change or capitalize on potential impacts -- may affect U.S. national security interests even more than the physical impacts of climate change itself," he said. The report, the "National Intelligence Assessment on the National Security Implications of Global Climate Change to 2030," relied on U.S. government, military, academic and United Nations studies of climate change. It is the first time the U.S. intelligence community has issued such a comprehensive report on the subject.