WASHINGTON — Global warming is likely to have a series of destabilizing effects around the world, causing humanitarian crises as well as surges in ethnic violence and illegal immigration, according to an assessment released Wednesday by U.S. intelligence agencies.
Rising temperatures could weaken already fragile regimes around the world and create a new set of national security challenges for the United States over the next two decades, the report warns.
"Climate change alone is unlikely to trigger state failure" during that period, said Thomas Fingar, chairman of the National Intelligence Council, in remarks prepared for a joint congressional hearing.
"But the impacts will worsen existing problems -- such as poverty, social tensions, environmental degradation, ineffectual leadership and weak political institutions," Fingar said.
The report represents the U.S. intelligence community's most comprehensive assessment to date of the long-term security consequences of global warming. It also marks a reluctant foray into a politically charged topic.
Democrats and environmental activists praised the assessment, calling it formal acknowledgment by a key part of the government that the threat of rising temperatures is real.
But the report was also criticized, particularly by skeptics of global warming and people who oppose using U.S. intelligence resources to track something as amorphous as the environment.
"I think it was a pathetic use of intelligence resources," said Rep. Peter Hoekstra (R-Mich.), the ranking Republican on the House Intelligence Committee.
Hoekstra said the study did little to expand government officials' understanding of global warming and its consequences.
The document "didn't add anything I didn't already know," he said.
According to the report, the effects of global warming are likely to be most severe in sub-Saharan Africa, the Middle East and Central and Southeast Asia. Its authors warn that less rainfall and more volatile weather could cut agricultural output in some regions of Africa by as much as 50%.
"We judge that economic refugees will perceive additional reasons to flee their homes because of harsher climates," Fingar said. "Many likely receiving nations will have neither the resources nor interest to host these climate migrants," who might be carriers of infectious diseases.
