More and more countries understand the need for action, and there should be a worldwide commitment to reduce emissions and other global warming pollutants, Gore said.
"We have arrived at a moment of decision. Our home -- Earth -- is in danger," Gore said. "What is at risk of being destroyed is not the planet itself, of course, but the conditions that have made it hospitable for human beings."
"The Science is screaming at us," said Kerry, who, like Gore is a former Democratic Presidential candidate. Kerry also has his own tome on the threat of global warming.
"To the naysayers and the deniers out there, let me make it clear the little snow in Washington does nothing to diminish the reality of the crisis that we face," Kerry said.
The two former Presidential candidates ignored usual committee rules on time and for more than an hour with their opening statements and a riffing series of question and answer on what should be done.
The treaties and the cap-and-trade policy will have to follow, Gore said.
Unlike in testimony before Senate Environment Committee in 2007, Gore encountered no doubters as to the existence of climate change.
But there was some skepticism about how to address U.S. reliance on carbon-based fuel.
Sen. Johnny Isakson, R-Ga., said the United States should encourage more nuclear development.
"If you accept every dire circumstance of climate change and you take a clean and reliable source of energy off the table you make it much more difficult to get where you're going to," Isakson said.
Gore countered that private investors tend to be wary of nuclear development, which requires enormous investment up front. He said nuclear plants in Europe are financed mostly with public money.
Investing in energy efficiency, renewables, a unified national energy grid and clean cars will create millions of jobs, hasten the economic recovery and begin to solve the climate crisis, Gore said.
Gore also pointed to the increase in weather-related disasters -- fires, hurricanes and drought -- occurring due to climate changes that "will increase even more dramatically the longer we delay action on this."
Kerry said he would provide Gore's testimony to every member of the Senate.
"If ever there was an underscoring of the urgency, I think you've given it to us," Kerry said.