The man chosen by Donald Trump to be the new head of Nasa is a “climate change denier” who has “made a career out of ignoring science” and might disregard scientific advice about the safety of launching astronauts into space, US senators have warned.

Giving Tea Party congressman James Bridenstine the final say on whether to launch a manned space mission would, it was claimed, be “terrifying”.

But Mr Bridenstine was still confirmed in the job this week in a vote that split 50-49 along party lines – in contrast to the unanimous senatorial approval granted to all 12 previous Nasa leaders.

The confirmation of Mr Trump’s nominee came despite Mr Bridenstine telling Congress in 2013 that “global temperatures stopped rising ten years ago. Global temperature changes – when they exist – correlate with sun output and ocean cycles”.

Not only did this statement rely on debunked claims of a global warming “hiatus”, it also flatly contradicted the first sentence of the Nasa website page explaining the causes of climate change: “Most climate scientists agree the main cause of the current global warming trend is human expansion of the ‘greenhouse effect’.”

During a November confirmation hearing Mr Bridenstine softened his position slightly to accept that global warming is still happening and “human activity absolutely is a contributor to the climate change that we are currently seeing.”

But the Oklahoma congressman still refused to accept that humans were the primary drivers of climate change, instead saying: “It's gonna depend on a whole lot of factors. We're still learning more about that every day. In some years you could say absolutely. In other years during sun cycles and other things there are other contributing factors that would maybe have more than an impact."

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This again contradicted the website of Nasa, the organisation which Mr Bridenstine now leads, which states: “The intergovernmental panel on climate change, a group of 1,300 independent scientific experts from countries all over the world, concluded [that] industrial activities have raised atmospheric carbon dioxide levels from 280 parts per million to 400 parts per million in the last 150 years.

“The panel also concluded there's a better than 95 per cent probability that human-produced greenhouse gases have caused much of the observed increase in Earth's temperatures over the past 50 years.”

Mr Bridenstine’s apparent disagreement with the overwhelming scientific consensus prompted Brian Schatz to warn his fellow senators voting on whether to approve the congressman’s appointment: “Jim Bridenstine is a climate denier with no scientific background who has made a career out of ignoring science.

“And that is terrifying.

“This [Nasa administrator job] is about whether you are going to rely on people who actually know things, or rely on your own politics and your own ideology. When you have final launch authority you better rely on science.

“If something goes wrong people could die.”

The Hawaii senator was backed by Bill Nelson, the Democrat from Nasa’s home state of Florida, who said that the administrator who had the “final decision on the lives of astronauts” needed to be a “scientifically competent, consummate space professional, not a politician.”

Mr Nelson, a former astronaut, said: “From an understanding of Nasa’s history, and having lived through some of its darkest moments, I think what is not right for Nasa is an administrator who is not [adequately] prepared to be the last in line to make that fateful decision on ‘go’ or ‘not go’ for launch.”

In his 2013 speech, Mr Bridenstine demanded an apology from then president Barack Obama for the “gross misallocation” of research funds towards climate change, suggesting the money would be better spent on studying extreme weather forecasting and warning systems.

His appointment also comes amid concerns about the Trump administration’s apparent removal of references to global warming in official documents and websites, and its alleged block on government officials speaking about scientific research.

Mr Nelson alluded to both Mr Bridenstine’s speech and the Trump administration’s record when he warned: “Given Nasa’s mission to study the Earth, congressman Bridenstine’s past statements on climate change are troubling to say the least, particularly in this administration, where words like ‘science-based’ and ‘climate-change’ are being scrubbed from government documents, and where some scientists have been restricted from speaking publicly about scientific findings.

“Nasa needs a strong leader who understands the critical importance of studying the Earth, and is willing to put his job on the line to protect Nasa scientists.

“Congressman Bridenstine’s record suggests that he will do otherwise.”

Mr Bridenstine is a former Navy pilot with combat experience in Afghanistan and Iraq, who is also the executive director of the Tulsa Air and Space Museum.

Mr Bridenstine, who has also spoken out against gay marriage, has a triple major in economics, psychology and business from Rice University and a Masters of Business Administration from Cornell, but no formal academic qualifications in science subjects.