June 25, 2008  -- Global warming is likely to increase illegal immigration, create humanitarian disasters and destabilize precarious governments in political hot spots, all of which could affect U.S. national security, according to an assessment by U.S. intelligence agencies.

Sub-Saharan Africa, the Middle East and Central and Southeast Asia are most vulnerable to warming-related drought, flooding, extreme weather and hunger. The intelligence assessment warns of the global impact from the spillover: increased migration and "water-related disputes," according to prepared remarks by Tom Fingar, deputy director of national intelligence for analysis, who was scheduled to speak before a joint House committee hearing.

"We judge that the most significant impact for the United States will be indirect and result from climate-driven effects on many other countries and their potential to seriously affect U.S. national security interests," Fingar stated.

The national intelligence assessment on the national security implications of global climate change to 2030 is one of a series of periodic intelligence reports that offer the consensus judgment of top analysts at all 16 U.S. spy agencies on major foreign policy, security and global economic issues. Congress requested the report last year.

The assessment deals with the projected effects of climate change, and not just the negative ones. It predicts modest improvements in agricultural yields in North America and more water resources in South America. It predicts that most U.S. allies will have the means to cope economically. Fingar says, however, that unspecified "regional partners" could face severe problems.

Fingar states that the quality of the analysis is hampered by the fact that climate data tend not to focus on specific countries but rather on broad global changes.

Africa is among the most vulnerable regions, the report states. An expected increase in droughts there could cut agricultural yields of rain-dependent crops by up to half in the next 12 years.

Parts of southern and eastern Asia's food crops are vulnerable both to droughts and floods, with rice and grain crops potentially facing up to a 10 percent decline.

As many as 50 million additional people could face hunger by 2020, and the water supply - while larger because of melting glaciers - will be stressed by growing population and consumption. Between 120 million and 1.2 billion people in Asia "will continue to experience some water stress."

Latin America may experience increased precipitation, possibly cutting tens of millions of people from the ranks of those in want of water. But from 7 million to 77 million could still be short water resources because of population growth.

As Fingar represents it, the assessment strikes a considerably less ominous tone than a report issued a year ago by the Center for Naval Analyses on the same subject. That report, written by top retired military leaders, drew a direct correlation between global warming and the conditions that lead to failed states becoming the breeding grounds for extremism and terrorism.

"Climate change will provide the conditions that will extend the war on terror," stated Adm. T. Joseph Lopez, who commanded U.S. and allied peacekeeping forces in Bosnia in 1996.

"Weakened and failing governments, with an already thin margin for survival, foster the conditions for internal conflicts, extremism and movement toward increased authoritarianism and radical ideologies," the previous report said. "The U.S. will be drawn more frequently into these situations," stated the report, which drew on 11 retired generals and admirals.

The naval think tank report was a clarion call to reverse global warming with a reduction in greenhouse gas emissions.

Fingar's remarks are far more muted. Where the 63-page private report mentions terror or terrorism almost 30 times, his 21-page statement makes no mention of it. "Conflict" appears about 20 times in the think tank report. Fingar mentions "conflict" only twice, "disputes" once, and "ethnic clashes" once.