Category Archives: Climate science

"Risky Business" stands out in growing sea of climate reports

This blog post was co-authored by Gernot Wagner and first published on EDF Voices.

Put Republican Hank Paulson, Independent Mike Bloomberg, and Democrat Tom Steyer together, and out comes one of the more unusual – and unusually impactful – climate reports.

This year alone has seen a couple of IPCC tomes, an entry by the American Association for the Advancement of Science and the most recent U.S. National Climate Assessment.

The latest, Risky Business, stands apart for a number of reasons, and it’s timely with the nation debating proposed, first-ever limits on greenhouse gas emissions from nearly 500 power plants.

Tri-partisan coalition tackles climate change

The report is significant, first, because we have a tri-partisan group spanning George W. Bush’s treasury secretary Paulson, former mayor of New York Bloomberg, and environmentalist investor Steyer – all joining forces to get a message through.

That list of names alone should make one sit up and listen.

Last time a similar coalition came together was in the dog days of 2009, when Senators Lindsay Graham, Joe Lieberman, and John Kerry were drafting the to-date last viable (and ultimately unsuccessful) Senate climate bill.

Global warming is hitting home

Next, Risky Business is important because it shows how climate change is hitting home. No real surprise there for anyone paying attention to globally rising temperatures, but the full report goes into much more granular details than most, focusing on impacts at county, state and regional levels.

Risky Business employs the latest econometric techniques to come up with numbers that should surprise even the most hardened climate hawks and wake up those still untouched by reality. Crop yield losses, for example, could go as high as 50 to 70 percent (!) in some Midwestern and Southern states, absent agricultural adaptation.

The report is also replete with references to heat strokes, sky-rocketing electricity demand for air conditioning, and major losses from damages to properties up and down our ever-receding coast lines.

Not precisely uplifting material, yet this report does a better job than most in laying it all out.

Financial markets can teach us a climate lesson

Finally, and perhaps most significantly, Risky Business gets the framing exactly right: Climate change is replete with deep-seated risks and uncertainties.

In spite of all that we know about the science, there’s lots more that we don’t. And none of that means that climate change isn’t bad. As the report makes clear, what we don’t know could potentially be much worse.

Climate change, in the end, is all about risk management.

Few are better equipped to face up to that reality than the trio spearheading the effort; Paulson, Bloomberg and Steyer have made their careers (and fortunes) in the financial sector. In fact, as United States Treasury secretary between 2006 and 2009, Paulson was perhaps closest of anyone to the latest, global example of what happens when risks get ignored.

We cannot – must not – ignore risk when it comes to something as global as global warming. After all, for climate, much like for financial markets, it’s not over ‘til the fat tail zings.

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Reality check: Society pays for carbon pollution and that's no benefit

This open letter, co-authored by Gernot Wagner and first published on EDF Voices, was written in response to a New York Times article citing Dr. Roger Bezdek’s report on “The Social Costs of Carbon? No, The Social Benefits of Carbon.”

Dear Dr. Bezdek,

After seeing so many peer-reviewed studies documenting the costs of carbon pollution, it’s refreshing to encounter some out-of-the-box thinking to the contrary. You had us with your assertion that: “Even the most conservative estimates peg the social benefit of carbon-based fuels as 50 times greater than its supposed social cost.” We almost quit our jobs and joined the coal lobby. Who wouldn’t want to work so selflessly for the greater good?

Then we looked at the rest of your report. Your central argument seems to be: Cheap fuels emit carbon; cheap fuels are good; so, by the transitive property of Huh?!, carbon is good. Pithy arguments are fine, but circular ones aren’t.

First off, cheap fuels are good. Or more precisely, cheap and efficient energy services are good. (Energy efficiency, of course, is good, too. Inefficiency clearly isn’t.) Cheap energy services have done wonders for the United States and the world, and they are still doing so. No one here is anti-energy; we are against ruining our planet while we are at it.

The high cost of cheap energy

Yes, the sadly still dominant fuels—by far not all—emit carbon pollution. Coal emits the most. Which is why the cost to society is so staggering. Forget carbon for a moment. Mercury poisoning from U.S. power plants alone causes everything from heart attacks to asthma to inhibiting cognitive development in children. The latter alone is responsible forestimated costs of $1.3 billion per year by knocking off IQ points in kids. All told, coal costs America $330 to 500 billion per year.

Put differently, every ton of coal—like every barrel of oil—causes more in external damagesthan it adds value to GDP. The costs faced by those deciding how much fossil fuel to burn are much lower than the costs faced by society.

None of that means we shouldn’t burn any coal or oil. It simply means those who profit from producing these fuels shouldn’t get a free ride on the taxpayer. Conservative estimates indicate that carbon pollution costs society about $40 per ton. And yes, that’s a cost.

Socializing the costs is not an option

As someone with a Ph.D. in economics, Dr. Bezdek, you surely understand the difference between private benefits and social costs. No one would be burning any coal if there weren’t benefits to doing so. However, the “social benefits” you ascribe to coal are anything but; in reality they are private, in the best sense of the word.

If you are the one burning coal, you benefit. If you are the one using electricity produced by burning coal, you benefit, too. To be clear, these are benefits. No one disputes that. It’s how markets work.

But markets also fail in a very important way. The bystanders who are breathing the polluted air are paying dearly. The costs, if you will, are socialized. Society—all of us—pays for them. That includes those who seemingly benefit from burning coal in the first place.

Your claim that what you call “social benefits” of coal dwarf the costs is wrong in theory and practice. In theory, because they are private benefits. As a matter of practice because these (private) benefits are very much included in the calculations that give us the social costs of coal. What you call out as the social benefits of coal use are already captured by these calculations. They are part of economic output.

Our indicators for GDP do a pretty good job capturing all these private benefits of economic activity. Where they fail is with the social costs. Hence the need to calculate the social cost of carbon pollution in the first place.

So far so bad. Then there’s this:

Plants need carbon dioxide to grow, just not too much of it

In your report, you also discuss what you call the benefits of increases in agricultural yields from the well-known carbon dioxide fertilization effect. It may surprise you to hear that the models used to calculate the cost of carbon include that effect. It turns out, they, too, in part base it on outdated science that ought to be updated.

But their science still isn’t as old as yours. For some reason, you only chose to include papers on the fertilization effect published between 1902 and 1997 (save one that is tangentially related).

For an updated perspective, try one of the most comprehensive economic analysis to date, pointing to large aggregate losses. Or try this Science article, casting serious doubt on any claims that carbon dioxide fertilization could offset the impacts on agricultural yields from climate change.

Farmers and ranchers already have a lot to endure from the effects of climate change. There’s no need to make it worse with false, outdated promises.

Coal lobby speaks, industry no longer listens

It’s for all these reasons that, to borrow the apt title to the otherwise excellent New York Times story that ran your quote: “Industry Awakens to Threat of Climate Change”. And it’s precisely why the U.S. government calculates the social cost of carbon pollution. Yes, sadly, it’s a cost, not a benefit.

To our readers: Want to get involved? The White House has issued a formal call for public comments on the way the cost of carbon figure is calculated, open throughFebruary 26. You can help by reminding our leaders in Washington that we need strong, science-based climate policies.

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Why the cost of carbon pollution is both too high and too low

From EDF Voices:

Tell someone you are a “climate economist,” and the first thing you hear after the slightly puzzled looks subside is, “How much?” Show me the money: “How much is climate change really costing us?”

Here it is: at least $40.

That, of course, isn’t the total cost, which is in the trillions of dollars. $40 is the cost per ton of carbon dioxide pollution emitted today, and represents the financial impacts of everything climate change wreaks: higher medical bills, lost productivity at work, rising seas, and more. Every American, all 300 million of us, emit around twenty of these $40-tons per year.

The number comes from none other than the U.S. government in an effort to uncover the true cost of carbon pollution. This exercise was first conducted in 2010. It involved a dozen government agencies and departments, several dozen experts, and a fifty-page, densely crafted “technical support document,” replete with some seventy, peer-reviewed references and an even more technical appendix.

Cass Sunstein, the Harvard legal scholar of Nudge fame, who was co-leading the process for the White House at the time, recently declared himself positively surprised how the usual interest-group politics were all-but absent from the discussions throughout that process. This is how science should be done to help guide public policy.

The cost of carbon pollution is too low

The number originally reached in 2010 wasn’t $40. It was a bit more than half as much. What happened? In short, the scientific understanding of the impacts of rising seas had advanced by so much, and the peer-reviewed, economic models had finally caught up to the scientific understanding circa 2007, that a routine update of the cost of carbon number resulted in the rather dramatic increase to near $40 per ton. (There are twenty pages of additional scientific prose, if you want to know the details.)

In other words, we had been seriously underestimating the cost of climate change all along. That’s the exact opposite of what you hear from those who want to ignore the problem, and the $40 itself is still woefully conservative. Some large companies, including the likes of Exxon, are voluntarily using a higher price internally for their capital investment decisions.

And everything we know about the science points to the fact that the $40 figure has nowhere to go but up. The more we know, the higher the costs. And even what we don’t knowpushes the costs higher still.

Howard Shelanski, Sunstein’s successor as the administrator of the Office of Information and Regulatory Affairs (OIRA, pronounced “oh-eye-ruh”), has since presided over a further update of the official number. In fact, this one didn’t incorporate any of the latest science. It was simply a minor technical correction of the prior update, resulting in a $1 revision downward. (The precise number is now $37, though I still say $40 at cocktail parties, to avoid a false sense of precision. Yes, that’s what a climate economist talks about at cocktail parties.)

And once again, it all demonstrated just how science ought to be done: Sometimes it advances because newer and better, peer-reviewed publications become available. Sometimes it advances because someone discovers and fixes a small mathematical error.

Your input is needed

While announcing the correction, Shelanski added another layer of transparency and an opportunity for further refinements of the numbers: a formal call for public comments on the way the cost of carbon figure is calculated, open through January 27 February 26.

We are taking this opportunity seriously. EDF, together with our partners at the Natural Resource Defense Council, New York University School of Law’s Institute for Policy Integrity, and the Union of Concerned Scientists, is submitting formal, technical comments in support of the administration’s use of the cost of carbon pollution number as well as recommending further revisions to reflect the latest science.

The bottom line, as economists like to put it, is that carbon pollution costs society a lot of money. So as the technical experts trade scientific papers, you can help by reminding our leaders in Washington that we need strong, science-based climate policies.

Update (on January 24): The official comment period just was extended for another month, through February 26. More time to show your support.

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Correcting the maths of the "50 to 1 Project"

(This post first appeared on Climate 411.)

A nine-minute video, released earlier this fall, argues that climate mitigation is 50 times more expensive than adaptation. The claims are based on calculations done by Christopher Monckton. We analyzed the accompanying “sources and maths” document. In short, the author shows a disconcerting lack of understanding of climate science and economics:

  1. Fundamental misunderstanding of basic climate science: Pre-industrial levels of carbon dioxide (CO2) were at around 280 parts per million (ppm).[i] One of the most commonly stated climate policy goals is to keep concentrations below 450 ppm CO2. Monckton, oddly, adds 280 and 450 to get to 730 ppm as the goal of global stabilization efforts, making all the rest of his calculations wildly inaccurate.
  2. Prematurely cutting off analysis after ten years: Monckton calculates the benefits of the carbon tax over a ten-year time horizon. That is much too short to see the full effects of global warming or of the policy itself. Elevated carbon levels persist for hundreds to thousands of years.[ii]
  3. Erroneously applying Australian “cost-effectiveness” calculation to the world: This may be the most troubling aspect from an economist's point of view. Monckton first calculates the effect of the Australia-only tax on global temperatures, which is unsurprisingly low, as Australia accounts for only 1.2% of world emissions. Next, he calculates the tax’s resulting “cost-effectiveness” — defined as the Australian tax influencing global temperatures. No surprise once again, that influence is there, but Australia alone can't solve global warming for the rest of us. Then, Monckton takes the Australia-only number and scales it to mitigate 1ºC globally, resulting in a purported cost of “$3.2 quadrillion,” which he claims is the overall global “mitigation cost-effectiveness.” But this number simply represents the cost of avoiding 1ºC of warming by acting in Australia alone. Monckton has re-discovered the fact that global warming is a global problem! The correct calculation for a globally applied tax would be to calculate cost-effectiveness on a global level first. If Australia’s carbon price were to be applied globally, it would cut much more pollution at a much lower cost. And that, of course, is very much the hope. Australia, California, and the European Union are called “climate leaders” for a reason. Others must follow.

What’s the real cost of cutting carbon? The U.S. government’s estimate of the cost of one ton of CO2 pollution released today is about $40.[iii] That's also the optimal price to make sure that each of us is paying for our own climate damages. Any policy with a lower (implied) carbon price—including the Australian tax—easily passes a benefit-cost test.

With all due respect Lord Monckton, 3rd Viscount of Brenchley, your maths are way off.


[i] "Summary for Policymakers," IPCC Fifth Assessment Report, Working Group I (2013).

[ii] Results differ across scenarios, but a rough rule of thumb suggests that approximately 70% of the ‘peak enhancement level’ over the preindustrial level of 280 ppm perseveres after 100 years of zero emissions, while approximately 40% of the ‘peak enhancement level’ over the preindustrial level of 280 ppm persevered after 1,000 years of zero emissions (Solomon, Susan, Gian-Kasper Plattner, Reto Knutti and Pierre Friedlingstein, “Irreversible climate change due to carbon dioxide emissionsProceedings of the National Academy of Sciences 106, no. 6 (2009): 1704-1709). Note that this refers to the net increase in carbon dioxide in the atmosphere, not the exact molecule. Archer, David, Michael Eby, Victor Brovkin, Andy Ridgwell, Long Cao, Uwe Mikolajewicz, Ken Caldeira et al. "Atmospheric lifetime of fossil fuel carbon dioxide." Annual Review of Earth and Planetary Sciences 37 (2009): 117-134 discusses these two often confused definitions for carbon’s ‘lifetime,’ and concludes that 20-40% of excess carbon levels remain hundreds to thousands of years (“2-20 centuries”) after it is emitted. Each carbon dioxide molecule has a lifetime of anywhere between 50 to 200 years, according to the U.S. Environmental Protection Agency’s “Overview of Greenhouse Gases: Carbon Dioxide Emissions.” The precise number is under considerable scientific dispute and surprisingly poorly understood. (Inman, Mason, “Carbon is forever,” Nature Reports Climate Change 20 November 2008)

[iii] The precise value presented in Table 1 of the Technical Update of the Social Cost of Carbon for Regulatory Impact Analysis Under Executive Order 12866 for a ton of carbon dioxide emitted in 2015, using a 3% social discount rate increased is $38. For 2020, the number is $43; for 2030, the number increases to $52. All values are in inflation-adjusted 2007 dollars. For a further exploration of this topic, see Nordhaus, William D. The Climate Casino: Risk, Uncertainty, and Economics for a Warming World. Yale University Press (2013) as only one of the latest examples summarizing this kind of analysis. Nordhaus concludes that the optimal policy, one that maximizes net benefits to the planet, would spend about 3% of global GDP.

Many thanks to Michelle Ho for excellent research assistance.

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New York Times op-ed: Inconvenient Uncertainties

By Gernot Wagner & Martin L. Weitzman

The headline in The New York Times yesterday was succinct. “By 2047, Coldest Years May Be Warmer Than Hottest in Past, Scientists Say.” Not, say, “around 2050” or “within our lifetime.” The specificity makes the crisis feel real, imminent and terrible. Call it a convenient truth.

The story was about a new study published this week in the journal Nature that calculated that by 2047, the average temperature will be hotter across most parts of the planet than it had been at those locations in any year between 1860 and 2005.

In truth, attention to the year 2047 is misguided. Climate around the world has already changed to a point where we can perceive humanity’s fingerprint. Extreme weather events like the two hurricanes that hit New York City in the past two years are going to be only more intense in the future.

Continue reading at nytimes.com/opinion.

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Uncovering the Real Cost of Carbon

(This post was co-authored by Thomas Sterner and appeared first on EDF Voices.)

Last week, the Obama administration released new energy efficiency standards for microwaves, along with an update to the government’s official Social Cost of Carbon (SCC) figure. What do those two things have to do with each other? Well, the efficiency standards will help the planet by cutting the energy needs of microwaves, which will in turn save consumers money. And the new SCC numbers show just how expensive our addiction to fossil fuels has become.

The SCC is used to estimate the damages from carbon emissions (and the benefits from reducing those emissions) for the purposes of regulatory benefit-cost analyses. The central estimate for the SCC is now around $35 per ton of carbon dioxide pollution emitted today.

That’s the administration’s estimate of the damage—to human health, ecosystems, and the economy—caused by every ton of carbon dioxide emitted into the atmosphere. The average American emits about 20 tons each year.

The new cost of carbon figure is a welcome step forward, reflecting the latest versions of the underlying models. The bad news is that the increased number also shows that our lack of a comprehensive climate policy is becoming ever more costly.

Moreover, this updated SCC number underestimates the true costs of carbon emissions. For example, the current SCC quickly rises to $55 per ton under a lower discount rate (that is, an estimate that doesn’t “discount” harms to the wealth and health of future generations by quite as much as the administration did in reaching its $35 per ton figure).

The value of one ton of carbon dioxide would rise higher still with a declining discount rate, something that, in line with the general consensus among economists, would more closely reflect the true costs of climate change. And none of that includes the cost of extreme climate events.

Basing Policy on Science

The good news: the administration’s latest numbers show exactly how policy analysis should be done—rigorously and consistent with the latest advances in science and economics. For example, instead of using older versions of three main SCC models to calculate its official number, the administration now uses the most recent peer-reviewed versions of each. That simple but important step helps to bring the new official SCC more in line with the latest academic literature.

In short, the administration’s economics are slowly and carefully catching up with what we all can see outside our windows. While atmospheric carbon dioxide levels have just passed the 400 parts per million threshold for the first time in over 3 million years, the real costs of climate change keep piling on.

What the country really needs, of course, is for Congress to pass a comprehensive climate policy. Only then will Americans stop living in a world where their personal behavior leads to socialized costs of at least $35 for each of the 20 tons of carbon dioxide we emit every year. Until then, the Obama administration is right to at least include these costs in its own regulatory impact assessments.

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