Nassim Nicholas Taleb warns us about climate change

Summary:  This is the second post looking at statistician Nassim Nicholas Taleb’s insights about “ruin” risks, and what they tell us about climate change. Here we look at his warning about climate change and two factors he ignores: the duration of the climate risk window and the odds of a climate disaster. The danger is real but the stories that we face certain doom are wild exaggerations, which make rational preparation more difficult. The previous post was Nassim Nicholas Taleb looks at the risks threatening humanity.

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

Yesterday’s post examined a methodology developed by a team including Nassim Nicholas Taleb for identifying “ruin” risks, where the result is non-recoverable for global civilization — or even the biosphere (described in “Mathematical Foundations for the Precautionary Principle“).

They wrote a note applying their method to one of the major risk debates of our time: “Climate models and precautionary measures” in Science and Technology, in press. The authors are brilliant, and it states with unusual clarity common arguments for radical and immediate action to fight climate change. Here’s the core of their analysis (it’s worth reading in full).

“Those who contend that models make accurate predictions argue for specific policies to stem the foreseen damaging effects; those who doubt their accuracy cite a lack of reliable evidence of harm to warrant policy action. These two alternatives are not exhaustive. One can sidestep the “skepticism” of those who question existing climate-models, by framing risk in the most straight-forward possible terms, at the global scale. That is, we should ask ‘what would the correct policy be if we had no reliable models?’

“We have only one planet. This fact radically constrains the kinds of risks that are appropriate to take at a large-scale. Even a risk with a very low probability becomes unacceptable when it affects all of us –– there is no reversing mistakes of that magnitude.

“…While some amount of pollution is inevitable, high quantities of any pollutant put us at a rapidly increasing risk of destabilizing the climate, a system that is integral to the biosphere. Ergo, we should build down CO2 emissions, even regardless of what climate-models tell us.

“…This leads to the following asymmetry in climate policy. The scale of the effect must be demonstrated tube large enough to have impact. Once this is shown, and it has been, the burden of proof of absence of harm icon those who would deny it.”

This is logical jujutsu! Taleb declares that climate change is a “ruin” event, so we must do whatever is necessary to defend against it (see yesterday’s post) — no matter how low the probability of this risk, with  the burden of proof on the other side (those recommending a slower or smaller response).

Yesterday’s post showed the daft nature of that advice. There are many “ruin” threats (Taleb doesn’t list them); the relevant funding is that which “defends” against them all. Plus more expenditures to fight shockwaves that have only disastrous consequences. The total sums spent would be fantastic.

Back in the real world we have to consider not just the possible consequences of threats, but also their probability and timing (the oceans’ death in the next few decades vs. climate doom in the late 21st C). Let’s look at the latter two factors.

Timing of climate ruin

Cumulative Probability of Ruin for a small risk“No matter how small the probability, in time, something bound to hit the ruin barrier is about guaranteed to hit it. No risk should be considered a “one-off” event.” (From Taleb el al.)

How long do we have to worry about increasing CO2? What’s the window of concern?  Taleb reminds us of the question’s importance.

“No matter how small the probability, in time, something bound to hit the ruin barrier is about guaranteed to hit it. No risk should be considered a ‘one-off’ event. …The longer the t, the more the expectation operators diverge. …The longer the life expectancy T (expressed in time periods), the more serious the ruin problem. Humans and plant have a short shelf life, nature doesn’t …”

The era of rapid CO2 emissions is just a moment in history. Massive anthropogenic emissions of CO2 began around WWII (hence the IPCC’s AR5 finding that “It is extremely likely {>95% probability} that human activities have caused more than half of the observed increase in global average surface temperature since the 1950s.”

This era will end sometime in the late 21st century. The world population will drop with a fertility rate (TFR) below the replacement rate, energy efficiency will continue to increase, and new energy sources replace fossil fuels. All of these trends are happening today. TFR dropped by half from 1955 to 2015, to 2.5 (with new tech coming to depress it more). Use of coal is dropping around the world, use of renewables is increasing, and radical new sources are attracting private capital (e.g., fusion).

As a result, CO2 emissions peaked approximately a decade ago in most developed nations (e.g., US in 2007). Even at slow rates of change, the combined effect of these trends will eventually reduce our CO2 emissions to de minimis levels — but not necessarily before we get severe warming. If though some unforeseeable factors it does not do so, then rapid consumption would exhaust all economically recoverable deposits of fossil fuels before the end of the century (an ugly worst case scenario).

Also there are offsets to emissions which might become significant by the late 21st century. Such as greening of the world (forests are a CO2 sink), as more nations follow the trends in the US and Europe. US forest extent increased 6% from its trough in 1920 to 2012 (see table 3).

Our climate risk window is a few generations long. It will almost certainly end before 2100. What is the size of our danger during this century?

About those predictions of certain doom from climate change

USS Enterprise
In the extended RC8.5 scenario, Captain Kirk’s ship is powered by coal or oil.

The IPCC’s AR5 gave four scenarios of global warming, each representing a rate of warming resulting from assumed trends in population, technology, etc. The worst of the four was RCP8.5 (details here), a world in which major trends change for the worse. Population growth is in the top 20% of forecasts, as fertility in Africa doesn’t drop as it has everywhere else (details here). Technological progress halts. And improvements in energy efficiency stall. It’s often called a “business as usual” scenario, which is absurd given its assumptions.

Scientists take this bad news scenario, run it in climate models assuming high impacts from CO2, and get nightmarish outcomes. These worst case assumptions are speculative. The IPCC’s AR5 says the key variables are as yet only roughly estimated. The most important is equilibrium climate sensitivity, which they describe as known within a 6x range…

“{T}here is high confidence that ECS is extremely unlikely less than 1°C and medium confidence that the ECS is likely between 1.5°C and 4.5°C and very unlikely greater than 6°C.”

Some studies take this speculation to a higher level of absurdity. What levels of greenhouse gases do we get if the conditions of RCP8.5 continue for another 3 centuries? We get an answer in “The RCP Greenhouse Gas Concentrations and their Extensions from 1765 to 2300” by M. Meinshausen et al in Climate Change, November 2011 — They assume “constant emissions after 2100, followed by a smooth transition to stabilized concentrations after 2250 achieved by linear adjustment of emissions after 2150.” They describe a scenario in which the unlikely trends of RCP8.5 continue for the next three centuries, burning off most (or all) of the world’s fossil fuel resources to create a modern version of the Dark Ages.

To add wild speculation on top of wild speculation, take this scenario and run it through climate models to produce “The climate response to five trillion tonnes of carbon” by Katarzyna B. Tokarska et al, Nature Climate Change, in press. This paper describes the climate response to the RCP8.5 scenario if it runs to 2300. It paints the “Bleakest Picture of Our Future to Date“ in which CO2 will “scorch” the Earth“.


Worse case scenarios provide valuable guidance for decision makers and the public. But scientists’ and journalists often focus on these without adequate explanation, giving people an exaggerated picture of the magnitude and likelihood of climate disasters. At some point these becomes lies, inducing panic in the public for political purposes.

As people become aware of these misrepresentations, they lose confidence in scientists and journalists. This makes rational public policy to cope with climate change less likely. That’s bad, since there are potentially large unpleasant effects from climate change — even if it is not “ruin” for life on Earth.

Wildfire Earth

For More Information

Please like us on Facebook and follow us on Twitter. For more information see The keys to understanding climate change, My posts about climate change, all posts about shockwaves (high impact, low probability scenarios), and especially these about the rumored coal-driven climate apocalypse…

  1. Is our certain fate a coal-burning climate apocalypse? No!
  2. Manufacturing climate nightmares: misusing science to create horrific predictions.
  3. Good news! Coal bankruptcies point to a better future for our climate.
  4. Britain joins the shift from coal, taking us away from the climate nightmare.
  5. Good news from America about climate change, leading the way to success.
  6. Good news from China about climate change!

To learn more about the state of climate change see The Rightful Place of Science: Disasters and Climate Change by Roger Pielke Jr. (Prof of Environmental Studies at U of CO-Boulder, and Director of their Center for Science and Technology Policy Research).

The Rightful Place of Science: Disasters and Climate Change
Available at Amazon.

9 thoughts on “Nassim Nicholas Taleb warns us about climate change”

  1. This article is irresponsible. This is no time to dumb down the effects of climate change. It is time to act……… If you have a high risk of a bad outcome, you act…you factor this into the market. He is either willfully ignorant, perhaps even a fossil fuel shill, or extremely frightened and unable to reason.

    1. Dophins,

      When in foreign lands, do you attempt to communicate by speaking loudly and slowly in English?

      The public policy debate is about facts and logic, using the large body of data gathered by climate scientists. That’s how scarce resources are allocated among the many important needs facing our society.

      Why do you believe fact-free and logic-free screeds like yours have any effect? Why should they have any effect? Do we fund those who scream the loudest, and give the wildest insults?

      If you disagree with something in this post, state what and why. That you don’t like the conclusion is immaterial to other people.

    2. Dolphins, your understanding of climate is flawed. Fossil fuel shill? Did you know that the “climate change” scam was started by Biggest Oil Rockefellers and their front man, the late Maurice Strong? Does that make you a “big oil shill?” Oops! They’re far more clever than you or I; they play both sides of the game to control the outcome. Yes, we’re being played.

      This idea of acting without knowledge and based only upon hysteria is dangerous. The precautionary principle only works if you’re headed in the right direction. Jumping off the cliff is not the right direction. And promoting global cooling and a fear of warmth in an ongoing Ice Age interglacial (Holocene) is not only dumb and dangerous, it is highly irresponsible. Forcing the end of the Holocene would usher in the next glacial period and would kill Trillions (humans and animals).

      Taleb and his friends are working with flawed data, so their output is wrong. But the same can be said of most of us. We don’t know everything.

      Your buddies at the UN lie about climate all the time. They tell only enough truth to keep you and your fellow warming alarmists on the hook. I know, because I was part of your group. Then, I dug deeper and found out that I was wrong.

      Here’s an example. Global warming is good! Why? Because we currently live in an Ice Age interglacial and reside far closer to dangerous cold than to dangerous warmth. We could cool the planet 2C and kill billions from the cold and lack of rain. We could warm the planet 20C and life could thrive from equator to the poles. The only real problem is that people would have to move from the current coastlines, just as they did 10,000 years ago when global warming made civilization possible.

      Storms? Ask yourself what causes wind to blow. If you say heat, think again. Venus has plenty of heat, but has had zero wind for millions of years. Jupiter has very little heat (-108C), but the largest storms in the Solar system — at least one larger than the entire Earth. Why would England get hurricanes during the Little Ice Age? Look up the Great Storm of 1703, and the sinking of the Spanish Armada in 1588.

      Drought? Ask yourself how land ever gets water. If you think cooling the planet would give us more rain, you need a better education in simple physics. Rain doesn’t happen from cold alone. You need warmth to get the water from the oceans into the upper atmosphere. More warming, more water, more rain, more food, more life.

      You’ve been lied to. Suck it up and change your mind. Support life on this planet. The Rockefellers and their ilk have tons of money for their selfish game of planetary take-over and eugenics. They don’t care about you or dolphins. They care about power. And you’re falling into their plans.

    3. I think the suggestion that Taleb is using “logical jujitsu,” which is the starting point of the article’s argument, is completely incorrect. I can only conclude that author either misses or rejects Taleb’s key premise: if a risk whose probability is low, but its effects are known in binary fashion – 0=catastrophic; 1= non-catastrophic, and where “catastrophic = obliteration – then it’s probability cannot be used in standard risk assessment form. This is the whole point of “The Black Swan” and is simply an extension of the “robustness” argument set forth in that book.

  2. Pingback: Nassim Nicholas Taleb looks at the risks threatening humanity | Watts Up With That?

  3. Fascinating, but flawed. Taleb works on the assumption that the mainstream definitions are correct and they’re not. He buys into the notion that CO2 is a pollutant which is incredibly and 100% wrong. He says, “we should build down CO2 emissions, even regardless of what climate-models tell us.”

    Carbon dioxide is called a pollutant because the warming alarmists view global warming as bad and tie CO2 to recent warming. Both notions are completely wrong.

    Global warming is good. In fact, we are far closer to deadly global cooling than we are to any measure of problem from warming. Most people don’t realize that we currently still live in an Ice Age interglacial. Yes, that’s right. We still live in an Ice Age. Changing the name of the period doesn’t magically make those 2 little white things at the poles disappear. As long as they persist throughout the year, we still live in an Ice Age.

    Carbon dioxide shows zero correlation to warming, except as a product of warming (effect, not cause) on time scales of 10,000 to 100,000 years.

    Taleb, el al’s work looks promising, but it’s not quite ready for prime time. Like the old programmer’s maxim — garbage in = garbage out. And Taleb and his fellows still haven’t figured out how to deal with the garbage.

    Reduce CO2? That’s garbage. Plants have been starved for CO2 for millions of years. In fact, when CO2 plummeted down to 800 ppm (2x today’s levels), some 30 million years ago, plants freaked out and evolved C4 species because of the starvation levels. So, even Taleb gets it wrong. We need far more CO2 and far more warmth.

    You really, really, really do not want the Holocene to end with those 2 little white things at the poles still around. The only thing the warming alarmists got right is sea level rise, and that’s easy: people can move. But I dare you to feed 7+ billion people when all of Canada, half of USA, and half of Europe are buried under permanent snow.

  4. Pingback: Weekly Climate and Energy News Roundup #232 | Watts Up With That?

  5. There is a risk you are missing – that there is reason to believe that an irreversible temperature rise will be triggered before our technology is able to reduce C02 to a safe level again. Read up on this tipping point.

    1. Ron,

      “There is a risk you are missing”

      There are thousands of risks out there. They are called “shockwaves” — low probability, high impact scenarios. We can go broke attempting to prevent or prepare for them. See these posts, esp
      The first step to protecting the world from its many dangers.

      “Read up on this tipping point.”

      While its fun to read individual papers, they provide a weak basis for public policy — since many (perhaps most) prove to be wrong. That’s why we have the IPCC and major science agencies to assemble scientists’ work into a coherent picture — and show the consensus opinion. That is the best foundation for making sound public policy.

      As a starting point, look at the Summary for Policymakers to IPCC’s AR5 Working Group I report. Read up on it!

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