The idea that climate change is a vast global conspiracy -- involving everyone from Nasa and the British Met Office to Chinese government scientists and – has persisted in the United States to an alarming degree.

So much so that more than 180 members of Congress are believed to be climate deniers, including Senator Jim Inhofe, who once tossed a snowball to the presiding officer in February, saying: “You know what this is? It’s a snowball, from outside here. So it’s very, very cold out. Very unseasonable.” Washington DC gets an average of about 12cm (5 inches) of snow in February.

Now 31 major scientific organisations in the US – including the American Association for the Advancement of Science, the American Meteorological Society and the Society for Industrial and Applied Mathematics – have signed a joint letter to Congress urging them to accept that climate change is real and action needs to be taken.

“Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research concludes that the greenhouse gases emitted by human activities are the primary driver,” they write.

“This conclusion is based on multiple independent lines of evidence and the vast body of peer-reviewed science.

“There is strong evidence that ongoing climate change is having broad negative impacts on society, including the global economy, natural resources, and human health.

“For the United States, climate change impacts include greater threats of extreme weather events, sea level rise, and increased risk of regional water scarcity, heat waves, wildfires, and the disturbance of biological systems. The severity of climate change impacts is increasing and is expected to increase substantially in the coming decades.”

The letter adds that to reduce the risk of the “most severe” impacts of climate change, “greenhouse gas emissions must be substantially reduced”.

“In addition, adaptation is necessary to address unavoidable consequences for human health and safety, food security, water availability, and national security, among others,” the signatories say.

“We, in the scientific community, are prepared to work with you on the scientific issues important to your deliberations as you seek to address the challenges of our changing climate.”

Climate change protests around the world Show all 25 1 /25 Climate change protests around the world Climate change protests around the world People rally to promote climate protection in Rome, Italy Climate change protests around the world Hundreds of demonstrators gather in front of City Hall in Los Angeles, California EPA Climate change protests around the world People hold hands to form a human chain during a gathering called by ecologist organisations in Marseille, southern France, to protest against global warming a day ahead of the United Nations Conference on Climate Change (COP21) held in Paris Climate change protests around the world Demonstrators clash with French riot police during protests on Place de la Republique, ahead of the COP21 World Climate Change Conference 2015 in Paris, France Climate change protests around the world Demonstrators clash with French riot police during a protest on Place de la Republique ahead of the COP21 World Climate Change Conference 2015 in Paris, France Climate change protests around the world A group of people perform during a rally to promote climate protection in Rio de Janeiro, Brazil Climate change protests around the world A protester sits next to his sign that reads 'Monsanto the Devil Incorporated ' as he joined hundreds of demonstrators who gathered in front of City Hall in Los Angeles, California EPA Climate change protests around the world Environmentalists dance during a protest near the Place de la Republique after the cancellation of a planned climate march following shootings in the French capital, ahead of the World Climate Change Conference 2015 (COP21), in Paris, France Reuters Climate change protests around the world People protest next to characters dressed as wild animals during a march against climate change near the Monument to the Revolution, in Mexico City AP Climate change protests around the world Protesters carries a banner while they take part in a protest about climate change at New York City Hall steps in lower Manhattan, New York Reuters Climate change protests around the world People take part in a protest about climate change around New York City Hall at lower Manhattan, New York Reuters Climate change protests around the world People rally to promote climate protection in Piazza Castello, Turin, Italy Climate change protests around the world A woman holds a globe during a protest for the global climate day in Lugano, Switzerland Climate change protests around the world Yemenis hold banners as they participate in the Global March for Climate in the old city of Sanaía, Yemen Climate change protests around the world Protesters dressed as Santa Claus take part in a protest about climate change at New York City Hall steps in lower Manhattan, New York Reuters Climate change protests around the world People gather at the Legislative Palace in Montevideo, during the Global Climate March to demand action on climate change telling world leaders on the eve of a crunch UN summit that there is "no planet B". From Sydney to London, humid Rio to chilly New York, at least 683,000 hit the streets in 2,300 events across 175 countries at the weekend, co-organiser and campaign group Avaaz said, calling it the largest number of people to protest over climate change all at once Getty Images Climate change protests around the world Climate change protests around the world Demonstrators participate in the Global March for Climate in Athens, Greece Climate change protests around the world A man wearing a Bernie Sanders mask leads hundreds of demonstrators who marched near City Hall in Los Angeles, California EPA Climate change protests around the world Patricia Hauser joined hundreds of demonstrators who gathered in front of City Hall in Los Angeles, California Climate change protests around the world A woman holds a poster of a sick Earth as she joined hundreds of demonstrators who gathered in front of City Hall in Los Angeles, California EPA Climate change protests around the world Hundreds of demonstrators march around City Hall in Los Angeles, California EPA Climate change protests around the world A demonstrator holds cut-out of US Democratic Presidential candidate Bernie Sanders as she joined hundreds of demonstrators who gathered in front of City Hall in Los Angeles, California EPA Climate change protests around the world George Patten holds a sign that reads 'No Fracking Ever!' as he joined hundreds of demonstrators who gathered in front of City Hall in Los Angeles, California EPA Climate change protests around the world Gabrielle Sosa wears 'Rising Sea Levels' sign as she joined hundreds of demonstrators who gathered in front of City Hall in Los Angeles, California EPA

They can expect a frosty reception from some, particularly Mr Inhofe, who chairs the Senate Committee on Environment and Public Works and is also the author of The Greatest Hoax: How the Global Warming Conspiracy Threatens Your Future.

Last year, during the talks about the Paris climate agreement, Mr Inhofe told a meeting of sceptics: “I look forward to hearing what kind of cover-up deal emerges from this international climate conference.