In a predictably contentious hearing, the Senate's environment and public works committee heard from a lead scientist for the UN's climate body, the IPCC, on the growing evidence linking extreme weather and climate change.
"It is critical to understand that the link between climate change and the kinds of extremes that lead to disaster is clear," Christopher Field, a lead author of the IPCC report and director of global ecology at the Carnegie Institute for Science, said in testimony.
"There is no doubt that climate has changed," he went on. "There is also no doubt that a changing climate changes the risks of extremes, including extremes that can lead to disaster."
He later told the committee that those climate-related disasters would have profound effects on industry and agriculture.
Field was the first IPCC scientist to appear before the committee since February 2009. It was a time when there was real optimism about prospects for action on climate change under the new Obama Administration.
By Wednesday, however, it was universally acknowledged there was no prospect of moving climate change legislation through Congress. There was also little chance the scientists' presentations would persuade the most prominent Republican climate contrarian, Senator Jim Inhofe, who told the committee: "The global warming movement has completely collapsed."
Senator Barbara Boxer, the California Democrat who chairs the committee, also noted she had deliberately avoid calling any administration officials or government scientists.
The Republican's campaign against Obama's green agenda, with their attacks on the Environmental Protection Agency and his clean energy loans, would make their presence a political distraction, she indicated.
But Boxer told reporters before the hearing she had faced growing pressure from the public to air the issue of climate change. The Republican-controlled House has turned down 15 requests from Democrats for a similar hearing.
Field, in his testimony, warned that the devastating extremes of the last year could soon become routine.
"The US experienced 14 billion-dollar disasters in 2011, a record that surpasses the previous maximum of 9," he said. "The 2011 disasters included a blizzard, tornadoes, floods, severe weather, a hurricane, a tropical storm, drought and heatwaves, and wildfires. In 2012, we have already experienced horrifying wildfires, a powerful windstorm that hit Washington DC, heat waves in much of the country, and a massive drought."
He went on to make a point of warning Texans that the future of farming and ranching could be put in jeopardy because of climate change.
The committee also heard from James McCarthy, a Harvard oceanographer and IPCC author, who warned that sea-level rise was occurring about three times faster than scientists believed even a decade ago.
The hearing quickly veered off course from reviewing the latest climate science to the intractable politics surrounding climate change in America.
In one of the liveliest exchanges, Bernie Sanders of Vermont continued his effort to take down Inhofe for his statements that climate change is a hoax and a conspiracy.
Sanders asked the scientists on the panel for their opinions on some of Inhofe's more notorious assertions – that climate change is a hoax, that the planet is actually in a state of cooling, and that such environmental concerns were a conspiracy by the UN, Al Gore, and Hollywood.
The scientists did not support Inhofe's claims.