Tag Archives: climate science

Karl Popper explains how to open the deadlocked climate policy debate

Summary: Many factors have frozen the public policy debate, but none more important than the disinterest of both sides in tests that might provide better evidence — and perhaps restart the discussion. Even worse, too little thought has been given to the criteria for validating climate science theories (aka their paradigm) and the models build upon them. This series looks at the answers to these questions given us by generations of philosophers and scientists, which we have ignored. This post shows how Popper’s insights can help us. The clock is running for actions that might break the deadlock. Eventually the weather will give us the answers, perhaps at ruinous cost.

“Confirmations should count only if they are the result of risky predictions; that is to say, if, unenlightened by the theory in question, we should have expected an event which was incompatible with the theory — an event which would have refuted the theory.”
— Karl Popper in Conjectures and Refutations: The Growth of Scientific Knowledge (1963).

“I’m considering putting “Popper” on my list of proscribed words.”
— Steve McIntyre’s reaction at Climate Audit to mention that Popper’s work about falsification is the hallmark of science, an example of why the policy debate has gridlocked.

This graph creates a high bar for useful predictions by climate models

Global fossil carbon emissions

From the Department of Energy’s Carbon Dioxide Information Center.

What test of climate models suffices for public policy action?

Climate scientists publish little about about the nature of climate science theories. What exactly is a theory or a paradigm? Must theories be falsifiable, and if so, what does that mean? Scientists have their own protocols for such matters, and so usually leave these questions to philosophers and historians or symposiums over drinks. Yet in times of crisis — when the normal process of science fails to meet our needs — the answers to these questions provide tools that can help.

A related but distinct debate concerns the public policy response to climate change, which uses the findings produced by climate scientists and other experts. Here insights about the dynamics of the scientific process and the basis for proof can guide decision-making by putting evidence and expert opinion in a larger context.

A previous post in this series (links below) described how Thomas Kuhn’s theories explain the current state of climate science. This post looks to the work of Karl Popper (1902-1994) for advice about breaking the gridlocked public policy debate about climate change. At the end of this post is the best-known section of his work about this.

Popper said scientific theories must be falsifiable, and that prediction was the gold standard for their validation. Less well known is his description of what makes a compelling prediction: it should be “risky” — of an outcome contrary to what we would otherwise expect. A radical new theory that predicts that the sun will rise tomorrow is falsifiable by darkness at noon — yet watching the dawn provides little evidence for it. Contrast that with the famous 1919 test of general relativity, whose prediction was contrary to that of the then-standard theory.

How does this apply to climate science?

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New research: Social scientists look for climate denial – and find it

Summary: The social science literature about climate change includes many oddities. A new hot paper about climate denial adds to that list, and illustrates why the climate policy debate has become gridlocked.


Another social science study of climate deniers makes waves on the Left: “Text-mining the signals of climate change doubt” by Constantine Boussalis and Travis G. Coan in the highly-ranked journal Global Environmental Change, January 2016. The abstract reads like real news…

“…This study contributes to the literature on organized climate scepticism by providing the first systematic overview of conservative think tank sceptical discourse in nearly 15 years. Specifically, we

  1. compile the largest corpus of contrarian literature to date, collecting over 16,000 documents from 19 organizations over the period 1998–2013;
  2. introduce a methodology to measure key themes in the corpus which scales to the substantial increase in content generated by conservative think tanks over the past decade; and
  3. leverage this new methodology to shed light on the relative prevalence of science- and policy-related discussion among conservative think tanks.”

“We find little support for the claim that “the era of science denial is over” — instead, discussion of climate science has generally increased over the sample period.”

The authors execute these goals described in the three bullets with detail and skill. From which they draw the conclusion of the last sentence. But their evidence provides little support for that conclusion; it is almost irrelevant to it. They state their conclusions in more detail. …

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Daniel Davies’ insights about predictions can unlock the climate change debate

Summary: Here are three powerful insights by Daniel Davies about predictions by experts. He used them to predict the outcome of the Iraq War. This post applies them to the public policy debate about climate change; you can use them to provide insights on other intractable problems.  This is another in a series about validating the case for public policy action to fight climate change.


Daniel Davies is a London-based analyst and stockbroker; he writes at his blog and the Leftist website Crooked Timber. Here he explains how he was able to accurately predict the disastrous outcome of our invasion of Iraq (different entirely from the theory-based predictions of those using history and 4GW). It is well-worth reading in full. His insights have great power and apply to many business and public policy issues — such as climate change. Excerpt…

… Here’s a few of the ones I learned {at business school} which I considered relevant to judging the advisability of the Second Iraq War.

Good ideas do not need lots of lies told about them in order to gain public acceptance.

I was first made aware of this during an accounting class. …

Fibbers’ forecasts are worthless.

Case after miserable case after bloody case we went through, I tell you, all of which had this moral. … If you have doubts about the integrity of a forecaster, you can’t use their forecasts at all. Not even as a “starting point”. …

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Yesterday’s Senate hearing shows why climate policy has gridlocked

Summary: Here is the video and transcript of a revealing discussion at yesterday’s Senate hearing about climate change. It shows in miniature how the debate about public policy to fight climate change has become gridlocked.

Cover of "Turning the Tide On Climate Change" by Robert Kandel

Cover of “Turning the Tide On Climate Change” by Robert Kandel (2009)

Hearing by the Senate Commerce Committee:
“Data or Dogma? Promoting Open Inquiry in the Debate
Over the Magnitude of the Human Impact on Earth’s Climate”.

I recommend attention to the Q&A at the hearing between Senator Ed Markey (D-MA), Judith Curry (Prof Atmospheric Science, GA Inst Tech), and Mark Steyn (arts reviewer and conservative activist, introduced by Senator Cruz as “an international bestselling author, a Top Five jazz recording artist, and a leading Canadian human rights activist”).

You can see a video of the hearing and the witnesses’ written testimony at the Senate website. Here is Prof Curry’s verbal testimony. The witnesses mostly rehashed material long-familiar to anyone following both sides of the debate (but, as usual, astonishing to the majority following only one side).

I found the Q&A more interesting, as it nicely illustrates why this important issue has become gridlocked — and policy discussions like Kabuki (formal opera, predictable but entertaining).

The transcript appears below, followed by a few comments by me.

——————– Computer-generated transcript ——————–

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Manufacturing climate nightmares: misusing science to create horrific predictions

Summary: Scientists and journalists bombard us with news about the coming climate catastrophe, described as certain unless we drastically change our economy. This has plunged many into despair. The hidden key to these forecasts is RCP8.5, the worst case scenario of the IPCC’s Fifth Assessment Report — often erroneously described as the “business as usual” scenario. Understanding this misuse of science reveals the weak basis of the most dire warnings (which set the mood at the Paris Conference), and helps explain why the US public assigns a low priority to fighting climate change despite the intense decades-long publicity campaign.

“We’re going to become extinct. Whatever we do now is too late.”
— Frank Fenner (Prof emeritus in microbiology at the Australian National U); Wikipedia describes his great accomplishments), an interview in The Australian, 10 June 2010.

Climate nightmares

In the IPCC’s Fifth Assessment Report four scenarios describe future emissions, concentrations, and land-use. They are Representative Concentration Pathways (RCPs), the inputs to climate models that generate the IPCC’s projections. Strong mitigation policies lead to a low forcing level of 2.6 W/m2 by 2100 (RCP2.6). Two medium stabilization scenarios lead to intermediate outcomes in RCP4.5 and RCP6.0.

RCP8.5 gets the most attention, with its bold and dark assumptions (details here). It is a useful and important scenario, a warning of what might happen if the 21st century goes badly. It should spur us to act. Unfortunately, “despite not being explicitly designed as business as usual or mitigation scenarios” RCP8.5 has often been misrepresented as the “business as usual” scenario — becoming the basis for hundreds of predictions about our certain doom from climate change.

The result of this (part of a decade-long campaign) is widespread despair among climate scientists and more broadly, among Leftists. This misuse of RCP8.5 is a triumph of propaganda, but polls show its ineffectiveness (with climate change ranking at or near the bottom of public policy concerns). Yet each month brings more of the same.

What future does RCP8.5 describe?

“In 2002, as I edited a book about global climate change, I concluded we had set events in motion that would cause our own extinction, probably by 2030. I mourned for months …”
— “Apocalypse or extinction?” by Guy McPherson (Prof Emeritus of Natural Resources and Ecology, U AZ), Oct 2009.

The papers describing the RCP’s clearly state their assumptions, unlike most of those that follow them. RCP8.5 describes a bleak scenario, a hot and dark world in 2100 (since it’s powered by coal, perhaps literally dark) — even before considering the effects of climate change. Below are the key points, with graphs from “The representative concentration pathways: an overview” by Detlef P. van Vuuren et al in Climatic Change, Nov 2011.

RCP8.5 assumes breaks in long-term trends for population growth and technological change, the opposite of the usual base case for planning. See this post for a more detailed look at it.

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Assigning blame for the flooding of Pacific atolls

Summary: Polar bears and pacific atolls (flooded by rising seas) are the poster children for climate change. Oddly, both are weak examples. Previous posts discussed polar bears. Here Judith Curry (Prof Atmospheric Science, GA Inst Tech) discusses the effect of rising sea levels on coral atolls.

Fanning Island, Kiribati

Fanning Island, Kiribati

Kiribati crisis: the blame game

Small atoll islands may grow, not sink, as sea level rises.
Judith Curry, posted at Climate Etc, 1 November 2015
Reposted under her Creative Commons License

Recent headlines highlight the plight of Kiribati:

Can we blame climate change, or more specifically sea level rise, for the problems of the atoll islands?  From a June 2 article in the New Scientist Small atoll islands may grow, not sink, as sea level rises, we find:

Rising seas are eating away at small islands and will eventually turn their inhabitants into climate refugees, right? Not so for some of the world’s most threatened islands, which have grown despite experiencing dramatic sea level rise.

After poring over more than a century’s worth of data, including old maps and aerial and satellite imagery, they conclude that 18 out of 29 islands have actually grown. As a whole, the group grew by more than 18 hectares, while many islands changed shape or shifted sideways. “There is still considerable speculation that islands will disappear as sea level rises,” says Kench. “Our data indicates that the future of islands is significantly different.”

Storms and other disturbances that churn up the sea seem to be more important than sea level in influencing stability, says Kench. Storms break up coral, which then gets deposited on the atolls. He says other coral reef islands are likely to evolve in the same way, and that the Maldives seem to be showing a similar effect.

“There will be less emphasis on external migration of ‘environmental refugees’ from atoll nations that has gained such prominence in the last few years,” he says. But he notes that the atoll-building sediment comes from productive coral reefs, which face a range of threats such as warming oceans and pollution.

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A way to break the gridlock on the climate change debate

Summary: The public policy debate about climate change consists largely of people tossing confetti at one another, with the reasonable people either pushed to the sidelines or buried. There is a simple step that both sides can agree on, with the potential to break the gridlock. Here’s a brief version of my proposal.

Trust can trump Uncertainty.”
Presentation by Leonard A Smith (Prof of Statistics, LSE), 6 February 2014.

The most important graph from the IPCC’s AR5

Figure 1.4 from the IPCC's AR5

Figure 1.4 from AR5: Estimated changes in the observed globally and annually averaged surface temperature anomaly relative to 1961–1990 (in °C) since 1950 compared with the range of projections from the previous IPCC assessments. Click to enlarge.

After 26 years of debate, US public policy on climate change remains paralyzed. Polls show that it ranks near the bottom of American’s concerns. We even remain poorly prepared for a repeat of past extreme weather, such as a major hurricane hitting an East coast city – let alone future climate. Both sides rehash their arguments, accomplishing nothing.

Climate scientists can begin to restart the debate and rebuild public confidence: re-run the climate models from the first three IPCC assessment reports (ARs) with actual emission data (from their future). See if they can show that models predict the observed global temperatures with reasonable accuracy. The cost of this project would be small compared to the overall funding of climate research and a dot compared to the potential costs of climate change.

The famous “spaghetti graphs” — one the most-cited graphics from the ARs — shows the forecast of models used in each report vs. actual global average atmospheric temperature. They tell us little, as in the above graph from the most recent AR. It packs too much information into one graph, but does not show what we most want to know: the accuracy of their forecasts. Each line represents a temperature forecast with specific assumptions of greenhouse gas (GHG) emissions.

How well do the models work if input with accurate GHG emissions? The answer can provide a fair test of the major climate models, one acceptable to both sides in the policy debate. A brief explanation of the models shows why.

{Read the full article at Climate Scepticism.}

“In an age of spreading pseudoscience and anti-rationalism, it behooves those of us who
believe in the good of science and engineering to be above reproach whenever possible.“
P. J. Roach, Computing in Science and Engineering, Sept-Oct 2004 — Gated.

Other posts in this series

  1. How we broke the climate change debates. Lessons learned for the future.
  2. A new response to climate change that can help the GOP win in 2016.
  3. The full version: climate scientists can restart the climate change debate – & win.