Republicans and Democrats in the U.S. Senate are widely divided about how the nation should respond to the threat of climate change. But at least they can agree on one thing: It is happening.

Senators voted 98-1 on Wednesday to pass a 16-word amendment that simply declares climate change “is real and is not a hoax.” The measure, proposed by Sen. Sheldon Whitehouse, D-R.I., is affixed to a broader GOP-backed bill to approve the controversial Keystone XL oil pipeline.

Still, the nearly unanimous vote belies the extent to which senators agree on the science of climate change. Sen. Jim Inhofe, R-Okla., a prominent climate denier and critic of the Obama administration’s environmental agenda, said that while he agrees the climate is changing, he doesn’t think humans are to blame. “The hoax is that there are some people who are so arrogant to think that they can change the climate,” he said on the Senate floor after signing on as a co-sponsor of the amendment.

A follow-up amendment from Sen. Brian Schatz, D-Hawaii, to clarify that humans "significantly" contribute to climate change failed by a vote of 50 to 49.

Prevailing climate science indicates that humans are largely responsible for the rise in global temperatures in the past century. Industrial activities like burning oil, coal and natural gas and destroying rainforests have pumped greenhouse gases into the atmosphere at levels unprecedented in human history, according to the United Nations-led Intergovernmental Panel on Climate Change. In a November report, the panel observed that “human influence on the climate system is clear and growing, with impacts observed on all continents.”

Inhofe and many congressional Republicans are staunch opponents of U.S. President Barack Obama’s proposals to cut carbon dioxide pollution from power plants and to slash methane emissions in the oil and gas sector. Many argue the policies would cripple American energy production, jeopardize jobs and raise energy costs for families and businesses. But policymakers still express doubt that such measures are even necessary, given what they claim is a tenuous link between human activity and global warming.

The majority of Americans -- 80 percent -- say they believe climate change is occurring, according to a December survey by Munich Re America, the world’s largest reinsurance firm. Of that group, about 60 percent say that man-made causes are to blame.

Obama in his State of the Union address Tuesday night made some of his strongest comments to date about the need to confront the climate crisis. “No challenge -- no challenge -- poses a greater threat to future generations than climate change,” he said. The president also mocked GOP policymakers who claim they can’t answer questions about climate change because they’re not scientists. "Well, I’m not a scientist, either. But you know what  --  I know a lot of really good scientists at NASA, and NOAA, and at our major universities," Obama said during the 63-minute speech.

The Wednesday amendment is part of a broader effort by Senate Democrats to hamper the main Keystone XL legislation. Two separate amendments that were rejected Tuesday would have required the Canada-to-Texas pipeline to use only U.S. materials in its construction and supply crude oil strictly for U.S. consumption. A third measure to promote energy efficiency passed by a vote of 94-5.