Although there is an important role for scepticism in science, for almost 30 years some corporations have supported a disinformation campaign about climate change science.

While it may be reasonable to be somewhat sceptical about climate change models, these untruths are not based upon reasonable scepticism but outright falsification and distortions of climate change science.

These claims have included assertions that the science of climate change has been completely "debunked" and that there is no evidence of human causation of recent observed warming. There are numerous lines of evidence that point to human causation even if it is not a completely settled matter. Reasonable scepticism cannot claim that there is no evidence of causation and some other claims frequently being made by the well-financed climate change disinformation campaign, and they amount to an utter distortion of a body of evidence that the world needs to understand to protect itself from huge potential harms.

On 21 October, 2010, John Broder of the New York Times, reported that "the fossil fuel industries have for decades waged a concerted campaign to raise doubts about the science of global warming and to undermine policies devised to address it".

According the New York Times article, the fossil fuel industry has "created and lavishly financed institutes to produce anti-global warming studies, paid for rallies and websites to question the science, and generated scores of economic analyses that purport to show that policies to reduce emissions of climate-altering gases will have a devastating effect on jobs and the overall economy."

Disinformation about the state of climate change science is extraordinarily – if not criminally – irresponsible, because the consensus scientific view is based upon strong evidence that climate change:

• Is already being experienced by tens of thousands in the world;

• Will be experienced in the future by millions of people from greenhouse gas emissions that have already been emitted but not yet felt due to lags in the climate system; and,

• Will increase dramatically in the future unless greenhouse gas emissions are dramatically reduced from existing global emissions levels.

Threats from climate change include deaths and danger from droughts, floods, heat, storm-related damages, rising oceans, heat impacts on agriculture, loss of animals that are dependent upon for substance purposes, social disputes caused by diminishing resources, sickness from a variety of diseases, the inability to rely upon traditional sources of food, the inability to use property that people depend upon to conduct their life including houses or sleds in cold places, the destruction of water supplies, and the inability to live where has lived to sustain life. The very existence of some small island nations is threatened by climate change.

As long as there is any chance that climate change could create this type of destruction, even assuming, for the sake of argument, that these dangers are not yet fully proven, disinformation about the state of climate change science is extraordinarily morally reprehensible if it leads to non-action in reducing climate change's threat. In fact, how to deal with uncertainty in climate change science is an ethical issue, not only a scientific matter, because the consequences of delay could be so severe and the poorest people in the world as some of the most vulnerable.

The corporations that have funded the sowing of doubt on this issue are clearly doing this because they see greenhouse gas emissions reduction strategies as adversely affecting their financial interests.

This might be understood as a new type of crime against humanity. Scepticism in science is not bad, but sceptics must play by the rules of science including publishing their conclusions in peer-reviewed scientific journals and not make claims that are not substantiated by the peer-reviewed literature. The need for responsible scepticism is particularly urgent if misinformation from sceptics could lead to great harm.

We may not have a word for this type of crime yet, but the international community should find a way of classifying extraordinarily irresponsible scientific claims that could lead to mass suffering as some type of crime against humanity.

• Donald Brown is associate professor in environmental ethics, science and law at Penn State University. The full version of this article was first published on the Penn State website.