When assessing doomsday claims about climate change promulgated by politicians, public figures and scientists themselves, it is important to consider where those claims come from and what is incentivizing the people making the claims. The problem is that everyone in the climate change arena, from the most sober scientists to the most devout activists, is incentivized to avoid null or inconclusive results about the effects of climate change and magnify the positive results. The result is a hype machine that cascades rapidly from uncertain and heavily debated conclusions in academic circles to the “certain” claims that citizens are bombarded with in the media.

A systemic problem in all scientific fields is that null results are rarely published, and in the area of climate science, this problem often manifests in scientists only publishing results that show a positive link between human activity and climate change or results that highlight an observed or predicted effect of climate change. Scientific governing bodies that interact with policymakers amplify the positive claims because their purpose depends on the existence of a problem and their ability to study it and offer solutions. The Intergovernmental Panel on Climate Change (IPCC) is the most glaring example of this conflict of interest. Finally, the activist movement that has coalesced around climate science has built a powerful publicity machine that magnifies claims further because their purpose depends on spurring the public and policymakers to adopt their philosophies and goals.

Because of this perverse, self-perpetuating incentive structure, the climate change hype machine doesn’t require an active conspiracy to operate. It simply requires all of these parties to act in their own self-interest, which they already perceive to be aligned with the interest of humanity as a whole, and draw similarly minded people to work with them. Using the release of the IPCC’s reports as an example, here is how the hype machine usually works, as shared by climate scientist Caleb Rossiter:

  • Public figures, news editors, and commentators make claims that are more alarmist than what individual IPCC authors say at the release of the report.
  • Individual IPCC authors make claims at the release of the report that are more alarmist than what the official press release says.
  • The official press release makes claims that are more alarmist than what the report’s summary for policymakers says.
  • The summary for policymakers makes claims that are more alarmist than the various chapters of the reports.
  • The report itself makes claims that are more alarmist than the studies they reference in the footnotes.
  • The studies referenced in the footnotes make cautious claims about trends spotted in a small number of locations or in a global computer model, and the authors acknowledge that their conclusions are based on uncertain measurements of highly complex phenomena with many interacting causes.

As a more specific example, let’s consider the release of the IPCC Special Report in October 2018, which attempted to summarize the consequences of warming greater than 1.5°C above pre-industrial levels.

At the top level, former vice president Gore went on the PBS Newshour and spoke repeatedly about how the report was further evidence that “… global warming could end human civilization as we know it.” He said that statements about the issue need to be “torqued” because scientists were too cautious with their words for politicians and the public to listen.

At the UN author level, Cornell physicist Natalie Mahowald, with a bit more caution, said in summary, “For some people, this is a life or death situation, without a doubt.”

At the press release level, things were more staid. “Every extra bit of warming matters, especially since warming of 1.5°C or higher increases the risk associated with long-lasting or irreversible changes,” said Hans-Otto Pörtner, Co-Chair of IPCC Working Group II.

The summary for policy-makers was calmer still. “Climate models project robust differences in regional climate characteristics between present-day and global warming of 1.5°C, and between 1.5°C and 2°C. These differences include increases in: mean temperature in most land and ocean regions (high confidence), hot extremes in most inhabited regions (high confidence), heavy precipitation in several regions (medium confidence), and the probability of drought and precipitation deficits in some regions (medium confidence).”

The technical summary of the report offered similarly sober statements. “Substantial changes in regional climate occur between 1.5°C and 2°C (high confidence), depending on the variable and region in question (high confidence).”

The studies cited go to further lengths to delineate the uncertainties, which are completely lost in the translation to the public statements. One of the studies, which appeared in Environmental Research Letters, accurately summarizes the difficulties of climate research. “The advantage of climate model based approaches is that large samples of climate with and without human emissions can be simulated, which in turn can be used to estimate the probabilities. Climate models, however, suffer from incomplete process knowledge and other model uncertainties. The advantage of observational approaches is that they can utilize the power of real-world observations. This comes, however, at the cost of strong simplifying assumptions, which may introduce biases to the analysis.”

Avoiding simplifying assumptions and uncertainties is impossible in such a complicated field, and the authors are not wrong to acknowledge those issues and then attempt to build a model anyway. Good science is all about traversing uncertain terrain. The problem is that if they did not achieve their goal of drawing a clear link between warming and drought in Europe, their “null” or “inconclusive” result would almost never be published in an academic journal. Who would publish or read a paper where the conclusion is “we built a model, and we didn’t observe anything”? Therefore, their endeavor is fundamentally fraught from the start.

The release of each IPCC report and the resulting doomsday claims clarify how scientists, policymakers, public figures, and the media are all incentivized to “find something” and “make an impact”. As a result, the hype machine generates calls for drastic changes to our entire economy from something that, at its core, is a difficult and uncertain science. This fact does not mean that we should disparage the science as a whole and not take any of its premises or conclusions seriously. Rather, we should take a sober look at the reality behind the public statements on climate change and be extremely careful about implementing any policy changes based on climate research.