In a letter published in the journal Science, more than 250 members of the US National Academy of Sciences, including 11 Nobel Prize laureates, condemned the increase in "political assaults" on scientists who argue greenhouse gas emissions are warming the planet.
The 'climategate' scandal and mistakes by the Intergovernmental Panel on Climate Change (IPCC) have led to a surge in attacks on climate scientists around the world.
In the US politicians have called for a criminal investigation of climate scientists, while in the UK eminent professors have received hate mail and even death threats.
In a strongly worded letter, the group of scientists likened the situation to the 'McCarthy era' in the US where anyone suspected of communist links was threatened with persecution. The period in the 1950s was named after the anti-communist pursuits of Senator Joseph McCarthy.
"We call for an end to McCarthy-like threats of criminal prosecution against our colleagues based on innuendo and guilt by association, the harassment of scientists by politicians seeking distractions to avoid taking action, and the outright lies being spread about them," the letter read.
The defence of climate science comes after a number of scandals cast doubt on the theory of man-made global warming. Emails stolen from the University of East Anglia (UEA) appeared to show scientists were willing to exaggerate temperature change in a scandal known as 'climategate', although two separate inquiries have found no evidence of misconduct.