A coalition of leading climate scientists yesterday filed a 48-page document to the US Congress refuting an attack on climate science made earlier this year by the Ukip deputy leader, Lord Christopher Monckton.

The detailed rebuttal addresses nine key scientific claims made by Monckton, a prominent climate sceptic, to a house select committee hearing in May. It includes the responses of 21 climate scientists who variously conclude that Monckton's assertions are "very misleading", "profoundly wrong", "simply false", "chemical nonsense", and "cannot be supported by climate physics".

Monckton, a former journalist and policy adviser to Margaret Thatcher, who has been the deputy leader of the UK Independence party (Ukip) since June, was invited by the Republican party to give evidence to the house select committee on energy independence and global warming.

His testimony included claims that increasing ocean acidification is not due to rising CO2 levels, that recent decades of warming were due to global brightening as opposed to rising CO2 levels, and that there is nothing unusual about recent rises in global temperatures. He concluded his testimony by stating that anthropogenic climate change is a "non-problem" and that the correct policy response was "to do nothing".

"For those without some familiarity with climate science, [Monckton's] testimony may appear to have scientific validity," said yesterday's response to Monckton's claims . "We have therefore undertaken the task of soliciting responses from highly qualified climate scientists in each of the areas touched upon in Monckton's testimony … In all cases, Monckton's assertions are shown to be without merit – they are based on a thorough misunderstanding of the science of climate change."

In response to the document, Monckton today told the Guardian: "It is unlikely that Congress will pay much attention to this. It displays a lamentable absence of quantitative detail, and a pathetic reliance on fashionable but questionable forecasting techniques that have long been compellingly contradicted by hard data."

The rebuttal was organised over the summer by five scientists, including Prof Michael Mann, the director of the Earth system science centre at Pennsylvania State University, and John Abraham, the associate professor of engineering at the University of St Thomas in Minnesota. Both scientists have sparred with Monckton in the past over his various claims about the veracity of climate science.

The document contains referenced responses from 21 leading climate scientists, including James Hansen, the director of the Nasa Goddard Institute for Space Studies, and David Easterling, the chief of the scientific services division at the US National Oceanic and Atmospheric Administration's National Climatic Data Centre (NOAA).

The document, entitled Climate scientists respond, is the latest attempt by climate science community to conduct a co-ordinated fight back against the barrage of attacks and criticism it has endured since thousands of private email exchanges between leading climatologists were taken from University of East Anglia servers last November and published online.

Responding to the document, Monckton said: "In a lengthy letter to Congress some months ago, in which I addressed questions from Congressmen about my testimony before the global warming committee, I had already refuted in detail the points now belatedly raised again by the scientists who have written to Congress. The scientists were unaware of my letter to Congress because they did not have the good sense or courtesy to contact me - or even to contact the vast majority of the scientists whose conclusions I had cited - before circulating to friendly news media their prolix, turgid, repetitive, erroneous and inadequate response to my testimony."

Monckton has been among the most persistent and vociferous of critics, labelling climate science as the "largest fraud of all time" and arguing that it is being used to establish a "new world government". In May, when John Abraham published a rebuttal online of a speech made by Monckton last year, Monckton threatened Abraham with legal action. During his congressional testimony in May, Monckton was mocked by a Democratic congressman for claiming that he was a member of the House of Lords during a previous committee hearing appearance in 2009. Last month, the clerk of the parliaments, wrote to Monckton, a hereditary peer, stressing that he should stop referring to himself as a member of the House of Lords.

• In the bulletpoint link to the document we referred to sceptics when we of course meant scientists. This has been amended