The Timeline of Climate Denial

Timeline of Climate Denial

The contemporary climate change debate is fiercely polarised between those who see it as the greatest existential threat, and those who see it as a hoax. By looking back at the history of the climate change issue, we can identify events and trends that contributed to creating such a toxic discourse. Like any body of knowledge, climate change has a complicated history. Some beliefs from the past have been very different to present day understandings, and this contributes to the disagreements we see today. However, climate change is not a purely scientific matter, it can only be fully understood through appreciation for the political and social events that surround it and that it impacts upon. For various reasons, the important events in climate politics have disproportionately taken place in the US, and so it is US politics that this timeline focuses on.

19th Century

  • The effects of greenhouse gasses in the atmosphere begin to be studied formally. Greenhouse effect is thought to keep the world warm.

  • GHGs (Greenhouse Gasses) thought to trap radiation and warm the earth.

  • CO2 is experimentally observed to trap radiation.

  • Many different theories are proposed to explain climate variation that has been observed throughout history: volcanic activity; solar variation; ocean currents, etc. Experts at the time were not convinced by any of them in particular

  • Basic calculations of the extent of the greenhouse effect are made, concluding that global temps will rise and fall with CO2 levels. Svante Arrhenius (right), one of the leaders of the project, thought that warming due to human CO2 emissions would be slow and beneficial in the long term.


  • Attempts to recreate the warming effects of CO2 in the lab lead to inconclusive evidence.

  • CO2 was seen to absorb radiation of an overlapping range of frequencies to water vapour. This suggested that additional CO2 may have limited effect on the overall amount of radiation absorbed and heat trapped because water vapour was already absorbing most of the kinds of light that CO2 would absorb. Later discoveries show that there is little water vapour in the upper atmosphere, whereas there is CO2. This means that CO2 does in fact add to the greenhouse effect by absorbing radiation in the upper atmosphere, where there is no water vapour.

  • Many scientists assumed that excess CO2 will simply be absorbed by the oceans. Isotope analysis later shows that the dynamics of this process will allow atmospheric CO2 levels to rise because of the length of time between emission and absorption takes place.

  • Sunspot theory was established in 1920, leading to some believing that solar variations can explain historic climate changes. However, predictions of climate using solar theory consistently fail.


Nelson's Column obscured by smog, London
  • Smog, caused by aerosol pollution, becomes a serious local problem in many cities.

  • Scientists were unsure if the cooling effects of particulate pollution (aerosols), or the warming effect of GHG emissions would predominate. Increasingly, however, they began to suspect that human emissions could be disruptive of the climate in the 21st century.

  • The first climate models are produced. But they are not robust to small variations in input parameters, leading to large mispredictions much of the time.


  • Advances in computing allow for more precise calculations of the greenhouse effect.


  • American Petroleum Institute is warned by its own advisers of the possible dangers of increases in the global temperature.


  • Evidence that aerosols were increasing worldwide encouraged Reid Bryson and some others to warn of the possibility of severe cooling.

  • Evidence from the timing of ice ages relative to Earth's orbital cycles also leads to predictions of cooling.

  • The Northern Hemisphere undergoes a temperature decrease over 30 years to 1970. This leads to mistrust of expert warnings of the possibility of warming.


  • UN Conference on the Human Environment, Stockholm.

Environmental protesters, Stockholm 1972
  • The US delegation placed emphasis on institutional coordination, cooperative scientific research, and a few key environmental policies that resonated with Nixon's domestic constituents in traditionally “red” states. Nixon, remember, was a staunch anti-communist.

  • Issues promoted by the US included: ocean dumping, whaling, and world heritage sites (which mirrored the national park system in the US.

  • The US proposal contained significant support for environmental science, in particular research into the global atmosphere.

  • Nixon’s aides attempted to address environmental issues in terms favourable to US domestic and foreign policies. However, Sweden, China, and developing nations initiate diplomatic discussions that put environmental protection in the context of development, nuclear disarmament, and world peace. This leads to conflict with US geopolitical interests. The US is heavily criticised by China for the ecological warfare waged in Vietnam

  • Divisions begin to emerge created by the differing geopolitical concerns of the nations and the increasing awareness that environmental issues are highly relevant to these other concerns.


  • 3D global climate model was able to give a mostly accurate representation of the current climate, showing great progress compared to previous models. Many different models gave the same general results; increases in CO2 will lead to increases in temperature.

  • A paper was published on the importance of sunspots for global temperature, giving renewed credibility to the sunspot theory. Specific effects discussed could, however, also be linked with cycles of the North Atlantic.


  • Milankovitch cycles (variations in the earths movements) are shown to drive ice ages, proving the susceptibility of the climate to feedback amplification of small changes.

  • The Genesis Strategy is published by Steven Schneider. It popularises left learning policy solutions to climate threats.

  • Congressman Brown introduced the National Climate Program Act with Bipartisan support. This attempts to fix the fragmented climate surveillance of the federal government. The goal is to make resource planning more effective.

  • Much of the congressional interest in the National Climate Program Act came not from “prophets of doom” but from representatives of largely rural (red) states who wanted scientific agencies to meet their constituents' practical everyday needs. This included concerns about, heat, cold, storms, severe weather events, water, things that directly affect their constituents.


  • A National Academy of Science (NAS) reports the potentially catastrophic effects of increases in CO2 was released to the press. There was disagreement between scientists over the strength of these predictions.

  • It becomes clear that CO2 emissions measures would have economic effects, leading to increasing political attention. The new right which had grown up to oppose communism unites with business to oppose eco-radicalism.


  • NAS committee releases findings that CO2 doubling will lead to 1.5-4 degs warming.

  • Jimmy Carter’s problems in the Middle East led him to back synthetic fuels developed from coal. This puts climate scientist in an awkward position. He had previously been in favour of renewable energy.


James Hansen testifying to congress, 1988

  • Democrats like Al Gore begin to attack Reagan's environmental policies.

  • Democratic/ Environmentalist critique begins to make Reagan look anti-scientific leading to increasingly toxic debate.

  • Confrontational congressional hearings force scientists to take political sides

  • Clear conflict between the science of climate change and Reagans energy policy becomes apparent


  • Hansen publishes a paper on the climate impacts of rising CO2 and gives congressional testimony that alerts the public to its dangers. His predictions show temperature to rise faster than other scientists think it will.

  • Reagan is elected;

  • His energy policy is rhetorically promoted by: “cheap energy now!”

  • He slashes funding for social and environmental research. Department of Energy funding is cut by 1 billion dollars. Many scientists lose government jobs and are replaced by party line zealots.

  • James Watt was controversially appointed as Secretary of the Interior. His confirmation hearings allowed his drastically anti-environmentalist stance to be broadcast widely and led to a surge in donations to environmentalist organisations.

  • Old guard environmentalist Republicans were marginalised, leading to environmental organisations moving to the left.


  • A paper is published predicting that the firestorms created by large-scale nuclear conflict would create dramatic global cooling as a result of the aerosols release into the atmosphere. This created another conflict between US foreign policy and environmentalist goals. Rearmament by Reagan strongly opposed by scientists and environmentalists.

  • Publicly well know scientists Carl Sagan and Steven Schneider disagree over the details of the nuclear winter predictions


  • James Hansen testifies before a Senate committee on Energy and Natural resources. He describes a high degree of confidence in the causal relationship between rising atmospheric GHG levels and observed warming. Other scientists are less willing to make these claims so stridently. Coverage of this testimony leads to greater public awareness of the global warming issue.

  • The Intergovernmental Panel on Climate Change is established.

1988, and the establishment of the IPCC, marks the transition of climate change into a mainstream talking point. From this point onward climate change is no longer a niche issue but becomes a major node in the political discourse. Political movements become fully aware of the implications of the climate change issue for their ideological positions so they prepare their responses to it accordingly. The beginnings of formal and focused climate denial rise out of this as Republicans, and conservatives generally, realise that the issue itself creates problems for them, exacerbated by their weaponisation by the democrats/ left.

By Louder than the Storm Political Lead MacGregor Cox


READ MORE from this series on climate denial:

The Political Origins of Climate Denial

Uncertainty: A skeptics favorite tool

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