Sizzling June fires up greenhouse debate.

Showing rare ardor, Vice President Al Gore charged that Congress has tried to douse government discussion of global warming even as extreme temperatures have set records in the United States and across the world.

Gore and federal scientists reported last week at a White House press conference that the global average surface temperature for June hit an all-time high, far surpassing all other Junes since 1880. Each month of this year has shattered global temperature records, making the first half of 1998 substantially warmer than that of previous years, even the rest of the 1990s, already the hottest decade on record.

"This is so incredibly unusual--to have 6 months in a row where every single one of those months sets the record for being the hottest," Gore said.

The administration is currently battling Congress over whether to adopt policies aimed at curbing emissions of heat-trapping greenhouse gases, in accordance with an international treaty adopted last December in Kyoto, Japan. "The evidence of global warming keeps piling up. How long is it going to take before the people in Congress get the message?" asked the vice president.

El Nino helped warm Earth last year and early this year, but conditions in the tropical Pacific cooled off rapidly in June, says Thomas R. Karl, director of the National Climatic Data Center (NCDC) in Asheville, N.C. Nonetheless, global temperatures remained elevated throughout June and the first half of July.

"There's absolutely no question. Clearly, we have very compelling evidence to suggest that global temperatures are indeed warming," said Karl.

In the climate treaty known as the Kyoto Protocol, the United States agreed to cut its emissions of greenhouse gases by 7 percent from 1990 levels by 2012. Before the treaty becomes U.S. law, however, it must be ratified by the Senate, where it is currently stalled in committee. The House Appropriations Committee has sought to stifle public discourse on the issue, says Gore. It directs the administration to "refrain from conducting educational outreach or informational seminars on policies underlying the Kyoto Protocol until or unless the Protocol is ratified by the Senate."

As the political battle over global warming seethed in Washington, D.C., the southwestern and southeastern United States endured a withering drought and heat wave. The months of April through June were the driest on record for Florida, Louisiana, New Mexico, and Texas, according to the NCDC.

Karl offered snapshots of the extreme conditions. Amarillo, Tex.--less prone to extreme heat than Dallas--had 13 days in a row in June with temperatures topping 100 [degrees] F And Brownsville, Tex., went 17 days with the minimum temperature never dropping below 80oE

Meteorologists cannot determine whether any individual event, such as a heat wave, can be linked to greenhouse arming because weather can vary quite markedly on its own. Yet the recent events, says Karl, provide a taste of what will happen more frequently as the climate warms. For instance, the string of hot days in Brownsville would be predicted to occur in a stable climate once every 1,000 years. But if atmospheric greenhouse gases build at the present rate until the middle of the next century, such a heat wave would recur every 3 years, he says.

Computer climate models and theory predict that greenhouse warming will lead to more weather extremes, such as droughts and heavy rainfall. Already, U.S. episodes of severe rain have increased since 1910, says Karl.

Other climatologists, however, dispute some of the administration's numbers. "I think many of the temperature records are questionable," says George H. Taylor of Oregon State University in Corvallis. He is Oregon's state climatologist and the president-elect of the American Association of State Climatologists.

"The quality of data in many foreign countries is rather poor and data are sparse in many areas of the world," he says. What's more, as researchers have made their climate models more sophisticated, they have lowered their forecasts of how much temperatures will increase in the future, he adds.

Critics of the Kyoto Protocol say that the treaty lets developing nations continue to emit greenhouse gases without restriction and that it will slow the U.S. economy, costing millions of jobs nationwide.

Global temperatures for the first 6 months of each year, shown relative to the average.