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A new lease of life

Colin Summerhayes laments the rise of climate science denialism

14 May 2025

Melt water streams from an iceberg calved from the Ilulissat Glacier, West Greenland. With Donald Trump in the White House, denial of anthropogenic climate change has a new lease of life, notes Colin Summerhayes (© Alamy)

Strange things are in the wind. With the arrival of Donald Trump in the White House, environmental science has come under significant threat, and global warming denial has received a new lease of life. One of the hot beds of global warming denial in the USA – the Heartland Institute – has just become established in the UK and is already working with Nigel Farage (Horton & Quinn, 2025). The Institute has also been working with right-wing Members of the European Parliament to campaign against environmental policies (Horton et al., 2025). On the Trump agenda is the shrinkage of the Environmental Protection Agency, which advises on and implements environmental regulations, and the virtual cessation of climate change advice from NOAA (the National Oceanic and Atmospheric Administration), which collects and manages the USA’s weather and climate data. NOAA also works with similar agencies around the world to provide a global picture of climate change and sea level rise. Casting science away like this sets a dangerous precedent. Just because one doesn’t like what the science tells us, doesn’t mean it’s not true.

Climatic processes

As a palaeoclimatologist, I frequently come across individuals who tell me that there is no connection between CO2 and temperature. For the most part their ‘evidence’ comes from noticing that there is not a perfect match in time between rises and falls of temperature and CO2 recorded in ice cores. What they neglect are climatic processes basic to geology. Let’s look at how CO2 and temperature interact as the climate either warms out of a glacial period, or cools into one. Basically, as the ocean warms it releases dissolved gases, like CO2.

As a result there is an excellent match in timing between increasing insolation and CO2 release. But, in addition, warming melts glacial ice, raises sea level, and increases ocean area, thereby releasing yet more CO2. This connection breaks down when a glacial period begins. Cooling sets in as insolation decreases. But as ice forms on land, the sea level falls, which restricts the area of the ocean available to absorb CO2. At the same time, sea ice covers the polar ocean surface further restricting the ocean’s ability to absorb CO2. Thus, CO2 cannot fall as fast as temperature does, even though it will dissolve more in cold water. Furthermore, plant life decreases on land as tundra – a treeless biome – grows in the cold, so plants absorb less CO2 in cold times. Basic geology tells us that under these circumstances we should not expect a simplistic 1:1 relationship between CO2 and temperature ice age fluctuations.

It’s also now well understood that falling CO2 due to marine biological activity led to Snowball Earths, and that rising CO2 from volcanoes brought Snowball Earths to an end. So, warming can raise CO2, and rising CO2 can raise temperature. Denial of the linkage between CO2 and temperature is misplaced.

(Image by Pexels from Pixabay)

Climate science is no different from any other science in being a consensual social process (Oreskes, 2019). Climate scientists study the natural world to find things out, explain what they know and how they know it. Just like other scientists, they are linked to colleagues across the world and work as a community to robustly vet claims by reviewing articles, and through conferences, workshops and specialist meetings. Critical interrogation of results is mandatory. Published work is continually evaluated and judgements are made about the worthiness of candidates for tenured positions. Consequently, the track record of climate science has a substantial record of success in explanation, prediction, and providing the basis for successful action. In any scientific field, when a subject has been investigated for some time, scientists will converge on a consensus – that the universe is expanding, or that organisms evolve, or that greenhouse gases cause global warming, for example – because having investigated other possible causes, they found them wanting.

Hard decisions

Why is climate science, especially global warming, considered by some to be controversial? Much of the criticism of global warming science comes from the hydrocarbon industries or those they fund (Oreskes & Conway, 2010). That is because climate science findings are unwelcome to those vested interests, which are rich and powerful enough to lobby governments on their behalf, and to fund apparently independent think-tanks to spread their message to the unsuspecting public. Their messages, often through paid ‘so-called’ experts, spread through the Internet, YouTube and media outlets, which serve as their echo-chambers.

Because the discoveries of climate scientists imply a need to take actions contrary to those interests and their profitability, some in those industries misrepresent the scientific evidence for global warming, and manufacture doubt about it (as the tobacco industry did regarding claims that smoking caused cancer; Oreskes & Conway, 2010). They are not using scepticism to question the science so as to improve it, but rather to discredit it, and to confuse politicians and the public. And yet in 1984, E.E. David, the President of EXXON Research and Engineering Company, wrote “Few people doubt that the world has entered an energy transition away from dependence upon fossil fuels and toward some mix of renewable resources that will not pose problems of CO2 accumulation. The question is how do we get from here to there while preserving the health of our political, economic and environmental support systems” (David, 1984). EXXON knew by the late 1970s that hard decisions would be needed regarding changes in energy strategy. Those hard decisions have never been taken – because they would threaten profits.

Judging reliability

Widespread misrepresentation of climate science is not obvious to the general public (Bardon, 2019), for three main reasons:

  1. It is difficult for the public to access the latest climate science, which is published in scientific journals. Access to the articles and their data is often hidden behind publishers’ paywalls. To overcome that, colleagues and I write books (e.g. Summerhayes, 2020) for and lecture to the public about global warming and sea level rise.
  2. Difficulty in accessing the data forces the public to seek information about climate change on the Internet, a source of misinformation (incorrect or misleading) and disinformation (deceptive and a form of propaganda). This is a ‘new’ problem, because the Internet did not reach homes until the mid-2000s.
  3. Most major newspapers are owned by very rich people, many of whom support the excessive profit-making of the fossil fuel industries, and thus further denial of global warming.

Where can people go to judge how reliable climate science is? Obvious sources are the websites of the Royal Society (royalsociety.org), or professional scientific organisations like the UK’s Meteorological Office, or their equivalents elsewhere. The Geological Society of London provides a geological perspective on climate change (Lear et al., 2020). The UK’s Guardian newspaper is a reliable source of information. Books, too, carry a great deal of useful data (e.g. Krauss, 2021).

Confusion and discord

Before someone tries to beat me over the head with the infamous ‘hockey stick’ of climate change over the past 2,000 years, know that since its first publication in 1998, multiple studies carried out by different groups around the world have confirmed this picture (Neukom et al., 2014). At the tip of the ‘blade’ the last ten years have been the warmest in the observational record (Hansen et al., 2023). With a global average temperature rise of >1.5°C above pre-industrial levels, 2024 was the warmest year yet recorded in the modern era (EU Annual Climate Summary, 2024). 

Some people may have the impression of confusion, disagreement, or discord among climate scientists. That impression is false.

Despite the strong consensus within the climate science community that humans are causing global warming (Oreskes, 2004), some politicians, economists, journalists, and others may have the impression of confusion, disagreement, or discord among climate scientists. That impression is false. The scientific consensus might, of course, be wrong. But our grandchildren will surely blame us if they find that we understood the reality of anthropogenic global warming and failed to do anything about it.

Dr Colin Summerhayes

Geochemist and Oceanographer, Scott Polar Research Institute, University of Cambridge, UK

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