The US senate has voted by an overwhelming majority of 98-1 to confirm climate change exists and is "not a hoax".
The symbolic amendment, approved by both Republicans and Democrats, was attached to a bill which aims to approve the construction of the controversial Keystone XL oil pipeline, which would transport oil from Canada to the US and join up with existing pipelines.
Republican senator of Oklahoma James Inhofe, seen as one of the most outspoken deniers of climate change in the senate – even writing a book entitled The Greatest Hoax: How the Global Warming Conspiracy Threatens Your Future – announced he was supporting the legislation.
The only person who voted against the notion "It is the sense of the Senate that climate change is real and not a hoax" was Republican senator Roger Wicker of Mississippi.
However, a second vote which asked whether humans were responsible for climate change failed to pass the 60-vote threshold, with 50 senators agreeing human activity contributes to climate change compared to 49 who did not.
"This is a small victory but an important one," said Democratic senator Barbara Boxer.
"It means that there's a softening of the attitude of the deniers. They're losing ground in the face of public opinion."
Senator Brian Schatz, who introduced the failed notion that humans are responsible for climate change, said the vote had "exceeded my expectations."
"There is an emerging bipartisan group of people who believe that climate change is real and caused by humans and solvable," he added.
Inhofe received lukewarm applause when he announced he supported the idea that climate change is real, adding there had been was archaeological, historic and "biblical evidence" of its existence.
He added: "The hoax is, that there are some people who think they are so arrogant to think that they are so powerful that they can change the climate. Man can't change climate."
In 2013, sole 'No' voter Wicker said scientific data showed there is no conclusive evidence global temperatures are rising.
"President Obama continues to defend his aggressive policies with assertions that global temperatures are on the rise — a notion challenged by scientists and scholars," he said.
"The recorded temperatures were much lower than the predictions from climate models often cited by the president and global warming activists."