I posted this on Streetsblog yesterday, April 22, the 50th anniversary of Earth Day. It’s NYC-centric and doesn’t mention climate change (!). But its lessons apply nationwide, and good news is always welcome, especially now. PS, there is Covid-19 content, toward the end. — CK.

On Thanksgiving Day in 1966, I was driving from my parents’ home in suburban Long Beach, NY to dinner with family friends in Forest Hills, Queens. The air seemed extra bad. My eyes were teary, my nostrils were twitching and the radio was reporting some sort of pollution episode.

At that very moment, New York Times photographer Neal Boenzi was memorializing what the air looked like from a perch high up in the Empire State Building: smog shrouding skyscrapers like Met Life, NY Life and the Flatiron Building; smoke obscuring the financial district; the Hudson and East Rivers, invisible.

Fast forward 50 years to a mid-September weekday in 2016. Former New York City government official and activist Jon Orcutt steps onto the India Street Pier in Greenpoint, Brooklyn and aims his iPhone at east Midtown. The contrast of his photo with Boenzi’s couldn’t be more stark, and not because one was black and white while the other was color and digital. Ocutt’s picture glistens with mountaintop clarity. Zoom in, and every building — every window — is distinguishable. Billowing clouds adorn the sky, multitudes of pristine blue and pellucid white.

The distance between the photos attests to the past half-century’s clean-air revolution — a vast do-over to our nation’s skies, much of it led by New York City. Through citizen activism, enlightened governance and innovative technology, pollution levels were slashed across the board. No one knows the precise extent, but my best guess is that from the late sixties to today, citywide levels of noxious pollutants like PM2.5 (tiny particulates that invade and obstruct the lungs) and photochemical smog (a gaseous soup cooked by sunlight from nitrogen oxides and volatile organic compounds) fell by over 80 percent. Another lethal pollutant, sulfur dioxide, almost certainly declined even more. (The writer-activist Bill McKibben reported this week in his weekly New Yorker magazine climate newsletter that “air pollution has dropped by more than sixty per cent across America since 1970.”)

These improvements didn’t just enhance public health and cut medical costs. They also contributed to New York City’s economic resurgence. Here, too, no one knows precisely how much; polls don’t ask if cleaner air factored into people’s decisions to settle here. But my guess is that, after reduced street crime, cleaner air has been on a par with better schools and improved public transportation in attracting and retaining residents and businesses to New York.

No single regulation or program or anti-pollution device wrought these striking gains. Rather, a multiplicity of initiatives reduced air pollution levels here. These have probably been key:

• Lowering five- to 10-fold the sulfur content of fuel oil burned for heating and power generation*
• Tailpipe and engine technologies that cut per-mile auto emissions at least 10-fold
• Cleaner fuels and engines for diesel-powered heavy vehicles (still a work in progress)
• Investments in mass transit that stanched growth in auto travel (partly undermined by Uber)
• Widespread switching of dirtier oil-fired power, furnaces and boilers to natural gas
• Decommissioning in-building incinerators
• Controls on emissions from upwind sources such as refineries and power plants 

* = CTC readers will enjoy my 2009 post in Grist relating how NYC’s 1972 emergency surcharge on dirty oil — an early instance of Pigovian taxation — protected the city’s low-sulfur oil regulation from oil industry interference.

These developments didn’t happen by themselves. They were, and are, the most visible and impactful fruits of the environmental movement whose arrival 50 years ago as a political and cultural force we mark on Earth Day today. At its forefront were the Natural Resources Defense Council and NYC-based organizations such as Citizens for Clean Air (which preceded Earth Day), Straphangers Campaign and Transportation Alternatives (which came in its wake); indefatigable campaigners like Gene Russianoff, Marcy Benstock, Rich Kassel and the late Carolyn Konheim; and proactive city officials like Mayor John Lindsay, his Environment Commissioner Jerry Kretchmer, and engineering dynamo Brian Ketcham. In turn, these individuals and institutions were backed by (and often preceded and helped spark) federal environmental legislation enacted in the national upwelling of environmental activism that took full flower in the early 1970s.

It is true, and shameful, that, nationwide, communities of color today breathe dirtier air than wealthy, white areas (though in New York City there is surprising overlap between affluence and pollution). Even so, air quality has risen significantly in most environmental justice communities in recent decades, with more gains likely as ecological activism grows increasingly black- and brown-led, although that, of course, depends heavily on the outcome of the next election.

I have labored in recent years to foster appreciation of air quality progress, especially in New York City. Valorizing environmental regulations and, at least implicitly, the scientists, attorneys and activists whose labors and expertise brought them into being, isn’t just right, it’s an investment in protecting and enhancing our environment going forward.

Well, my project has a ways to go. Case in point: this statement in a recent New York Times story on a preliminary Harvard School of Public Health study linking higher levels of PM2.5 pollution with increased COVID-19 deaths:

If Manhattan had lowered its average particulate matter level by just a single unit, or one microgram per cubic meter [µg/m³], over the past 20 years, there would have been 248 fewer COVID-19 deaths in Manhattan by that point in the outbreak [April 5].

That framing is completely backwards, in my view. Rather than bemoaning the failure to reduce New York pollution levels by one hypothetical unit, we should be celebrating the reductions already accomplished. They are enormous: almost certainly more than 20 µg/m³ since 1970 (early baseline data for New York and other cities is sketchy). If the preliminary link between particulate pollution and COVID-19 mortality in the Harvard study is confirmed, then NYC’s pollution reduction since the time of Earth Day will be shown to have spared vast numbers of lives through population-level improved lung functioning.

(The linkage between polluted air and COVID-19 mortality is this, in a nutshell: the coronavirus kills primarily by ravaging people’s lungs, while chronic exposure to fine particulate matter and other air pollutants degrades lung functioning, rendering inhabitants of polluted areas more vulnerable once they’ve been infected. Conversely, the advent of cleaner air has given New Yorkers a hidden but sizable degree of immunity, relative to our susceptibility if the air had remained chronically polluted.)

It’s tempting to recast the pull-quote from the Times in terms of thousands of New York City COVID-19 deaths already averted, but I’m going to demur. For one thing, the hypothetical 248-lives figure there (which the Times article took directly from the preliminary Harvard paper) was calculated from a baseline of citywide deaths and ascribed (incorrectly) to Manhattan alone. More importantly, I’m not convinced that the correlation between PM2.5 pollution and COVID-19 mortality is as strong as the paper contends. Despite laudable effort by the authors, their county-level analysis may not have been fine-tuned enough to fully control for the 17 different possible confounding factors they included in their model such as population density and education levels.

Consider that from 2001 to 2017, a period rigorously analyzed by environmental-health experts at NYC’s Department of Health, citywide average PM2.5 levels declined from around 18 µg/m³ to around 10 (see graph). That’s a drop of 8 µg/m³ in just 16 years. If we extend that rate of improvement backwards to the three decades leading to 2001 — when many of the innovations I bulleted earlier were taking effect — the drop in PM2.5 in that period would be around 16 µg/m³. That would yield an overall reduction of 24 µg/m³ in fine particulate pollution levels from Earth Day to today.

But today, let’s lift our gaze from COVID-19 and epidemiology to New York’s clearer skies. Dear reader, please join me in toasting a half-century of scientist and activist vision and grit that has made — and continues to make — our city cleaner, healthier and more beautiful.

[NB: This post is co-authored with Christopher Ketcham. A slightly different version was published earlier today in The Intercept under the headline “What The Coronavirus Pandemic Can Teach Us About The Climate Emergency.”]

One is that science’s prestige and value are being restored. Americans watching Trump’s circus-like coronavirus daily briefings see National Institutes of Health immunologist Dr. Anthony Fauci stepping in to correct the president’s dangerously ignorant commentary. Similarly, we know it is the community of front-line doctors, nurses, and health care workers who will care for the sick; the epidemiologists and science journalists who will inform the public’s response; and trained chemists, biologists, and statisticians who will synthesize and prove the vaccines that will bring the pandemic to an end. As environmental legal scholar Michael Gerrard wrote last week, the climate change lessons of Covid-19 are to heed the warnings of scientists, do everything possible to minimize the hazards they predict, and prepare to cope with the impacts that remain.

Second, the crisis is helping us see just how much our well-being depends on muscular, proactive governance. Government of the people and for the people is literally the thing that’s now needed more than ever.  The people must be sovereign over corporations and not vice versa — a point driven home by the tepid response of big business to Trump’s exhortations to step up manufacture of equipment to protect health care workers.

Third, we may be shaking loose the defeatism that nothing can be done quickly. Take the example of those of us sheltering in place: We are learning, overnight, that simplicity isn’t necessarily austerity, frugality need not be privation, and that we can forgo quite a lot of our leisure and consumer entitlements if it serves some higher purpose — at present, to stop the sickening and death of our fellow human beings; in the longer run, to bend the rising curve of carbon emissions and put a hard stop on climate chaos.

Moreover, if our society can act, finally, to manufacture a million ventilators and a billion protective masks, surely we can within a few years act on a far grander scale to erect, say, a million wind turbines, insulate and solarize a hundred million buildings, carve ribbons of bicycle paths throughout our cities and suburbs, and so on. With the pandemic enforcing a brutal but necessary reset, the NIMBYism that has impeded this kind of progress practically everywhere might be swept into the dustbin for good.

Most hearteningly, the crisis is instilling a renewed appreciation of social solidarity. The more we are forced to quarantine and isolate, paradoxically, the more we become cognizant of the need for mutuality and social relations and social conscience. As New York Times columnist Roger Cohen wrote yesterday, “If this plague that cares not a whit for the class or status of its victims cannot teach solidarity over individualistic excess, nothing will.”

My well-being depends on your not being sick. My ability to be fed depends on your ability to grow and transport and distribute food. My life is now literally in your hands, as you make decisions whether to restrain your activity in the public sphere, keep your distance, self-quarantine.

If we so fully need each other, how can I abide your not having affordable health care? In this moment when the precarity of half or more of American households is laid bare, how can I abide a government that places the well-being of billionaires — whose wealth each week generates more money than many of us earn in a lifetime — above that of the 90 percent of Americans who make less than $100,000 a year?

What does solidarity have to do with climate? Everything. People whose health is tenuous and whose pocketbook is empty can’t easily stand up for climate action, but they may do so if government has put them on a solid footing and, in the Green New Deal, provided a framework for paying them good wages to actually implement it.

Synergies abound. With the U.S. government providing direct payments to American households, it’s only a step or two to paying coal miners and cattle ranchers to become solar installers and wind farm maintainers. Enacting some form of guaranteed income, even just temporarily, could pave the way for the “carbon fee and dividend” approach to taxing carbon fuels without further burdening the less well-off. In a different vein, trading frenetic foreign travel for staycations could downsize socially destructive companies like Airbnb, making rental apartments more affordable and in turn diminishing long-distance commuting and slashing carbon footprints.

As for the super-rich, never have their fortunes been so fully revealed as hollow and corrosive. Worldwide, the wealthiest 5 percent of households collectively burn more carbon than the entire bottom half, according to a comprehensive new report from the University of Leeds. Could the past decade’s research and agitation on economic inequality now culminate, in the pandemic’s wake, in an insistence on transmuting extreme private wealth into a new collectively shared wealth of renewable energy and sustainable communities?

Table presents the calculations and assumptions underlying Carbon Tax Center’s assertion that economic disruption from the pandemic could cut 1 ppm from atmospheric CO2. For fuller discussion, follow link from “calculations” higher up in the text.This, more than fossil fuel divestment or class-action litigation, is the kind of program that will actually cast off the yoke of the fossil fuel empire upon which the portfolios of the super-rich depend. In the process, the toxic aspiration to join the super-rich could be swept aside. Bye-bye, lusting after commuter helicopters. Bye-bye, hungering for one’s own island. Bye-bye, legislatures purchased by dark money.

As for those in the rarified upper classes who, in Margaret Thatcher’s iconic phrasing, embrace the libertarian right-wing precept that “there is no such thing as society,” let’s hope they will be answered by the millions of commoners who see clearly, as the pandemic rages, that we are all in this leaky boat together.

Charles Komanoff, a New York City-based economist and activist, directs the Carbon Tax Center.  Christopher Ketcham, an upstate New Yorker, is author of “This Land: How Cowboys, Capitalism, and Corruption are Ruining the American West.”  

David Wallace-Wells, the writer for New York magazine who jolted us last year with his searing climate-change story, The Uninhabitable Earth, has posted a follow-up, UN Says Climate Genocide Is Coming. It’s Actually Worse Than That.

You guessed right, the sequel is about the new IPCC report. We began the week covering the report’s first-time recommendation of a high carbon price to drive emission reductions. We can’t fully do justice to Wallace-Wells’ latest with a summary — it’s too layered for that. To convey a sense of his argument and his urgency, we’re excerpting five key passages (disclosure: some are longer than mere sentences), with comments.

David Wallace-Wells: Barring the arrival of dramatic new carbon-sucking technologies, which are so far from scalability at present that they are best described as fantasies of industrial absolution, it will not be possible to keep warming below two degrees Celsius — the level the new report describes as a climate catastrophe. As a planet, we are coursing along a trajectory that brings us north of four degrees by the end of the century. The IPCC is right that two degrees marks a world of climate catastrophe. Four degrees is twice as bad as that. And that is where we are headed, at present — a climate hell twice as hellish as the one the IPCC says, rightly, we must avoid at all costs. (emphasis added)

Carbon Tax Center: It’s worse than that. The most likely “shape” of the planetary climate-damage curve (or function) is a quadratic. (See graphic, from our June 2017 post, Showing the Cost Side of the Damage Equation in a New Light.) Doubling the temperature rise doesn’t double the damage, it quadruples it. Tripling the rise magnifies the damage nine-fold. The silver lining, if there is one, is that each increment of temperature rise we can prevent through societal action pays back more than proportionately in damage avoidance.

DW-W [this sentence is from his previous passage]: New carbon-sucking technologies … are so far from scalability at present that they are best described as fantasies of industrial absolution.

CTC: We agree.

DW-W: Because the numbers are so small, we tend to trivialize the differences between one degree and two, two degrees and four. Human experience and memory offers no good analogy for how we should think about those thresholds, but with degrees of warming, as with world wars or recurrences of cancer, you don’t want to see even one.

CTC: Goodness, yet another way in which human cognition militates against fully grasping and grappling with climate change. We thought Dale Jamieson’s magnificent 2014 book, Reason in a Dark Time: Why the Struggle Against Climate Change Failed, and What It Means for Our Future, covered all the obstacles to understanding and action: It’s hard to attribute the myriad consequences we see in the world to climate change… Evolution built us to respond to “rapid movements of middle-sized objects,” not to the slow buildup of insensible gases in the atmosphere. And of course, climate change is the world’s largest and most complex “collective action problem,” in which each of us, acting on our own desires, contributes to outcomes we neither desire nor intend. And many more, to which Wallace-Wells has added the new one, above.

DW-W: Nothing in the IPCC report is news … not to the scientific community or to climate activists or even to anyone who’s been a close reader of new research about warming over the last few years. That is what the IPCC does: It does not introduce new findings or even new perspectives, but rather corrals the messy mass of existing, pedigreed scientific research into consensus assessments designed to deliver to the policymakers of the world an absolutely unquestionable account of the state of knowledge.

CTC: That’s helpful to those of us in the trenches. It aids us in seeing why the release of old news — include the lede that limiting the earth’s average temperature rise to 1.5°C is pretty much off the table — was served up by important media as news, period.

DW-W: The IPCC has also, thankfully, offered a practical suggestion, proposing the imposition of a carbon tax many, many times higher than those currently in use or being considered — they propose raising the cost of a ton of carbon possibly as high $5,000 by 2030, a price they suggest may have to grow to $27,000 per ton by 2100. Today, the average price of carbon across 42 major economies is just $8 per ton. The new Nobel laureate in economics, William Nordhaus, made his name by almost inventing the economic study of climate change, and his preferred carbon tax is $40 per ton — which would probably land us at about 3.5 degrees of warming. He considers that grotesque level “optimal.”

CTC: Yesterday we posted the comment by our colleague Thomas Sterner, declaring that Nordhaus’s “choice to label the 3.5°C [temperature rise] as optimal is … unfortunate.” Today we would rather dwell on the brighter side, that the IPCC for the first time called not just for a carbon price but for a high one, as we reported on Monday.

DW-W: A carbon tax is only a spark to action, not action itself.

CTC: Yes … and no. No, because a robust carbon tax will be far more than a mere spark — it will stimulate enormous changes in behavior, investment, decision-making and innovation, all of it toward vastly lessened use of carbon fuels. Yes, because the tax itself doesn’t reduce emissions, rather it instills incentives that will provoke the reductions.

We think the article is well worth reading. Let us hear your take.

Addendum, Sept 19: The Trump administration yesterday formally adopted the proposed rules we wrote about last week, below. The New York Times’ Lisa Friedman reports the details. 

“This is insane – it borders on criminality,” said California Gov. Jerry Brown yesterday about President Trump’s proposed revisions to Obama administration regulations on methane emissions from oil and gas wells.

Brown has authority to speak, and not just because on Monday he signed SB (California Senate Bill) 100, which commits the Golden State to a 100% carbon-free electricity sector by 2045. Brown’s entire 16-year career as governor (1974-1982 & 2008-2016) has been one of breathtaking, broad-based innovation in energy efficiency, renewable energy and environmental protection.

Not just in California but across the U.S., fridges and A/C’s consume less electricity, cars burn less gasoline, and tailpipes pollute less because Brown’s administrations pioneered the required engineering, regulations and politics. If any human being living or dead has done more than Gov. Brown to cut carbon emissions, I’d like to know her name.

The Obama reg’s targeted natural gas leakage, venting and flaring by requiring more frequent inspection of leaks from gas wells and pipelines and expedited repairs. The Trump revisions will cut inspection frequencies at wells and compressor stations and extend repair deadlines, as reported yesterday by Romany Webb, Senior Fellow and Associate Research Scholar at Columbia University’s Sabin Center for Climate Change Law. Watering down the Obama rules will mean more heat-trapping methane released to the atmosphere.

Exactly how much more methane is hard to pinpoint but EPA estimates appear to be around 50,000 excess tons in 2020, rising to just over 100,000 in 2025. (Those are the two years displayed in Table 1.1 of EPA’s Regulatory Impact Analysis; the figure rises over time because the Obama reg’s being watered down apply to new wells only.) We’ll use the approximate 2025 figure, 100,000 tons per year as representative of the next 10-15 years.

“Methane is a highly potent greenhouse gas,” Ms. Webb reminds us in her informative post, “trapping approximately 87 times more heat in the earth’s atmosphere than carbon dioxide in the first 20 years after it is released, on a pound-for-pound basis.” Applying that multiplier, the additional 100,000 tons of methane per year will have the same climate-change impact as 8-10 million tons a year of additional CO2.

Total U.S. emissions of CO2 currently run between 5 and 6 billion tons, while emissions of methane and other GHG’s add the equivalent of another 1 billion or so (all figures are in short tons and are approximate). The Trump/EPA rollback will thus add less than two-tenths of one percent (0.2%, or one part in 500) to America’s climate pollution emissions.

If the rollback’s numerical impact is so small, why is it so odious?

First, the Obama rules being watered down were the opposite of revolutionary; they adhered to the time-honored (and bipartisan) pollution-control paradigm of covering only new or expanded emissions sources, an accommodation that circumvents arguably costlier “retrofitting” of existing sources.

Second, they’re eminently doable. Inspecting and fixing leaky wells and other gas infrastructure is good housekeeping, pure and simple. And they’re easy to follow.

Third, the methane rules bring substantial co-benefits: They create jobs. They cut down on “local” (toxic) pollution. They protect workers. And they’re at least partially cost-offsetting since the saved methane can be delivered and sold.

Fourth, they’re a giveaway to an industry that needs none: the U.S. oil and gas sector. With over a quarter of a trillion dollars a year in profits, and with annual contributions to Congress nearing a third of a billion dollars a year, America’s oil and gas industry is the last segment of our society in want of more federal largesse. (Figures are from Oil Change International; contributions figure includes coal companies.)

Last, as OCI reminds us in its mission statement: The production and consumption of oil, gas, and coal are major sources of global warming, human rights abuses, war, national security concerns, corporate globalization, and increased inequality. Anything that further incentivizes fossil fuel extraction and usage, as the Trump-EPA methane reg rollback will do, only exacerbates that.

In short, the rollback is quintessential Trump: spiteful, short-sighted, ignorant, amoral.

Jerry Brown is right on Trump and right on climate. He’s wrapping up his lifetime of public service on the highest possible notes of policy, leadership and moral clarity. The opposite of what we suffer with the White House.

I’m tempted to call it the decade’s most important paper on the costs of climate damage. The paper, just published in the peer-reviewed journal, Environmental and Resource Economics, upends the long-prevailing approach for estimating the social cost of carbon, potentially laying the ground for putting the SCC (in dollars per metric ton of CO2) into triple digits, from the $44 figure stipulated in rule-making by the Obama White House.

Not only that, the paper presents a trio of climate-damage functions relative to the temperature rise, that let us calculate the estimated global cost to humanity from each global warming increment. The functions vary depending on whether they include so-called “catastrophic damages” from climate change as well as estimates of climate change’s potential drag on future growth in economic productivity.  Each function expresses that cost as the percent of future GDP lost per additional centigrade-degree in global-average temperature relative to the pre-industrial level. (Graph at left, with equation in bold, is the most conservative, i.e., slowest-growing, of the three graphs in the paper. All three are shown in the next graphic.)

The new paper, Few and Not So Far Between: A Meta-analysis of Climate Damage Estimates, is by Peter Howard, economics director at NYU Law School’s Institute for Policy Integrity; and Thomas Sterner, professor of environmental economics at the University of Gothenburg in Sweden. (Disclosure: Thomas and I have shared a warm personal friendship since the 1980s.) As the somewhat unwieldy title suggests, the paper combines data and results of prior analyses that sought to place a cost on future damages from climate change. In those analyses, “damages” are expressed as a percentage of future global economic product — a somewhat cold-blooded metric that nevertheless allows policy-makers to compare the impacts of climate change on human well-being to the costs of mitigation and adaptation.

The Howard-Sterner paper identifies several sources of bias in previous meta-studies of the temperature-damage relationship. There’s “duplicate bias,” by which early climate-damage models tended to be overly conservative but, because of their primacy, came to be cited multiple times, thus biasing downward the temperature-damage relationships in meta-studies. Moreover, methodological choices or constraints kept some analyses from accounting for non-market climate impacts such as reduced biodiversity or for so-called catastrophic impacts such as collapses of regional or global agriculture.

Earlier analyses also failed “to control for whether market impact estimates [of climate damages] included potential impacts on economic productivity,” write Howard and Sterner. Though it may appear bizarre, until recently many attempts to estimate the temperature-damage function deliberately excluded the prospect that climate change will erode societies’ ability to generate new wealth by inhibiting the accumulation of technological and intellectual capital, which are key drivers of economic productivity and growth. In recent years, renowned climate economist William Nordhaus, whose Dynamic Integrated Climate-Economy (DICE) model and long-time intellectual leadership have been integral to estimating the social cost of carbon, has come under criticism for excluding non-market, productivity and catastrophic climate impacts from his modeling.

As we wrote last Friday, in 2015 the Interagency Working Group (IWG) on the Social Cost of Carbon created by President Obama directed federal agencies to use a “social cost of carbon” equivalent to $37/ton in 2007 dollars. (Note that the official link to the IWG was scrubbed away by the Trump White House, in 2017.) That figure, which equates to $44/ton in 2017 dollars, was drawn in part from the “2013R” version of DICE.

In their paper’s conclusion, Howard and Sterner point out that updating DICE as per their findings “would increase the resulting SCC of the Interagency Working Group by between one-and-a-half to twofold.” While that’s true arithmetically, it’s an understatement of sorts, insofar as their conclusion states clearly that “Using the preferred [model] specification, we find that the 2015 SCC increases by approximately three- to four-fold depending on the treatment of productivity.” However, that increase is attenuated by the IWG’s decision to derive their SCC not only via DICE but with two other temperature-damage models, neither of which are addressed in the Howard-Sterner paper.

Thus, while the authors’ analysis would raise the estimate of the SCC derived solely from DICE by an estimated 209 percent, the need to average the increases for the DICE figures with the unchanged figures from the other models leads the overall increase to be considerably less, though a still substantial 63 percent. Even that lower rise boosts the social cost per ton of CO2 to $72, from the Obama administration’s $44 (both figures in 2017 dollars).

That change is important since it warrants recalibrating the panoply of cost-benefit and other calculations that carbon tax advocates, corporate carbon-cutters and others have been basing on the social cost of carbon during recent years. But there’s more, and here we return to the equation we highlighted (and graphed) in the chart at the top.

In their paper, Howard and Sterner tested various curve shapes to distill the set of temperature-damage relationships they sifted in their meta-analysis. Their most robust functional form was a simple quadratic, by which the total damage to global well-being (expressed as the lost percentage of global economic output) rises by the square of the temperature deviation from pre-industrial levels.

Quadratic curves start slowly and gather steam — much as, when an object is dropped from some height, the distance from its point of release increases more with each passing second. And so it appears with the Howard-Sterner climate-damage function, by which the additional societal damage from each new temperature increment is greater than the damage from the previous increment. (See table directly above.) In fact, the additional damage is a linear function of the temperature rise (as you calculus jocks will have noticed, since the first derivative of any quadratic function is a linear one).

The implications are obvious but nonetheless profound. Arresting climate change isn’t binary, whereby we either stop global warming in its tracks or we don’t. It is, literally, a question of degree, with the importance of reducing and stopping warming intensifying as global temperatures rise. While that appears obvious, experientially — discomfort rises more when the mercury climbs to 100F from 95F than from 90F to 95F; and what goes for heat effects should go for drowned coasts, extreme weather, ecosystem stress, and so forth — now there’s an equation to codify it.

Howard’s and Sterner’s quantification of the accelerating harm as global temperatures increasingly diverge from pre-industrial levels obliges humanity — all of us — to redouble our efforts to tax and eliminate fossil fuels and other greenhouse gas emitters at the fastest imaginable rate.

This fall marks the tenth anniversary of the Stern Review, the 700-page report to the U.K. government on the economics of climate change by a team headed by economist Nicholas Stern, who was then chair of the Government Economic Service. The report famously called climate change the greatest market failure in human history and argued persuasively that the costs of climate inaction would grossly outweigh any possible benefits, even assuming high returns from monies not expended in the near term to arrest climate change.

Lord Stern — he received a life peerage in 2007 — currently directs the Grantham Research Institute on Climate Change and the Environment at the London School of Economics. Last week he published an editorial in Nature, Economics: Current climate models are grossly misleading, in which he argues emphatically that climate damage models — which translate postulated global temperature increases into societal and environmental costs — are grossly biased toward undercounting costs.

The editorial builds on research by Lord Stern and colleagues at Grantham that we reported on two years ago. In a nod to Lord Stern’s prominence and the importance of climate-damage modeling, we reprint it here in full. — C. Komanoff

The twin defining challenges of our century are overcoming poverty and managing climate change. If we can tackle these issues together, we will create a secure and prosperous world for generations to come. If we don’t, the future is at grave risk.

Researchers across a range of disciplines must work together to help decision-makers in the public, private and non-profit sectors to rise to these challenges. Economists, in particular, need more help from scientists and engineers to devise models that provide better guidance about what will happen if we succeed or if we fail.

As the 2015 Paris agreement on climate change made clear, we must achieve a net-zero carbon economy this century. Doing so will require policies that drive innovation, investment and entrepreneurship. The political will to make the necessary decisions depends partly on improving the analysis and estimates of the economics of climate change. Then the consequences of unmanaged global warming can be weighed much more transparently against the investments and innovations necessary to mitigate it.

Current economic models tend to underestimate seriously both the potential impacts of dangerous climate change and the wider benefits of a transition to low-carbon growth. There is an urgent need for a new generation of models that give a more accurate picture.

Dark impacts

The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), published in 2013 and 2014, provided a comprehensive overview of the literature on the costs of action and inaction. But the assessment understated the limitations of the research done so far. Essentially, it reported on a body of literature that had systematically and grossly underestimated the risks of unmanaged climate change. Furthermore, that literature had failed to capture the learning processes and economies of scale involved in radical structural and technical change, and the benefits of reducing fossil-fuel pollution, protecting biodiversity and forests, and so on.

The IPCC pointed out¹ that estimates of losses resulting from a 2 °C increase in mean global temperature above pre-industrial levels ranged from 0.2% to 2% of global gross domestic product. It admitted that the global economic impacts are “difficult to estimate” and that attempts depend on a large number of “disputable” assumptions. Moreover, many estimates do not account for factors such as catastrophic changes and tipping points.

It is these hard-to-predict impacts that are the most troubling potential consequences of inaction. The next IPCC report needs to be based on a much more robust body of economics literature, which we must create now. It could make a crucial difference.

Many estimates of economic losses are based on the outputs of integrated assessment models (IAMs). These models attempt to combine the key elements of biophysical and economic systems. This is a worthy endeavour. Sadly, most IAMs struggle to incorporate the scale of the scientific risks, such as the thawing of permafrost, release of methane, and other potential tipping points. Furthermore, many of the largest potential impacts are omitted, such as widespread conflict as a result of large-scale human migration to escape the worst-affected areas.

For instance, there is evidence that temperature increases of 1.5 °C and 2 °C would lead to differing extents of sea-level rise and extreme weather events², with obvious implications for small island states and coastal communities. These differences are simply not represented in the flawed estimates of economic losses.

IAMs are also used to calculate the social cost of carbon (SCC). They attempt to model the incremental change in, or damage to, global economic output resulting from 1 tonne of anthropogenic carbon dioxide emissions or equivalent. These SCC estimates are used by policymakers in cost–benefit analyses of climate-change-mitigation policies.

Because the IAMs omit so many of the big risks, SCC estimates are often way too low. As a first step, the consequences being assessed should include the damages to human well-being and loss of life beyond simply reduced economic output. And the very large uncertainty, usually involving downward bias, in SCC estimates should always be made explicit.

As the IPCC acknowledged², published SCC estimates “lie between a few dollars and several hundreds of dollars”. These values often depend crucially on the ‘discounting’ used to translate future costs to current dollars. The high discount rates that predominate essentially assume that benefits to people in the future are much less important than benefits today.

These discount rates are central to any discussion of our hand in the fate of future generations. Most current models of climate-change impacts make two flawed assumptions: that people will be much wealthier in the future and that lives in the future are less important than lives now.

The former assumption ignores the great risks of severe damage and disruption to livelihoods from climate change. The latter assumption is ‘discrimination by date of birth’. It is a value judgement that is rarely scrutinized, difficult to defend and in conflict with most moral codes.

Costing transition

The other role of IAMs — to estimate the costs of climate-change mitigation — also suffers from major shortcomings.

The IPCC’s mitigation assessment³ concluded from its review of IAM outputs that the reduction in emissions needed to provide a 66% chance of achieving the 2°C goal would cut overall global consumption by between 2.9% and 11.4% in 2100. This was measured relative to a ‘business as usual’ scenario. Clearly, growth itself can be derailed by climate change from business-as-usual emissions.

So the business-as-usual baseline, against which costs of action are measured, conveys a profoundly misleading message to policymakers that there is an alternative option in which fossil fuels are consumed in ever greater quantities without any negative consequences to growth itself.

Crucially, IAMs generally omit the potentially huge costs of air pollution from fossil fuels — which are saved if alternative fuels are used⁴. IAMs struggle to describe developments in alternative energy. They fail, in general, to capture the feedback loops in the innovation process that interact across the economy, prompting institutional and behavioural change, possible discoveries and economies of scale. There is empirical evidence, for example, that the geographical location of researchers and inventors can affect whether a firm chooses to do clean or dirty innovation.

“Discount rates are central to any discussion of our hand in the fate of future generations.”

The initial investment required to catalyse the transition to a low-carbon pathway might lead to great economic benefits in the long run. These could go well beyond avoided climate risks⁵. The knowledge spillover from low-carbon innovation into the wider economy — for instance, a battery developed for electric vehicles being used in wheelchairs — seems to be greater overall than that from high-carbon-energy technologies⁶.

As engineers learn how to install, connect and repair technology cheaply, unit costs fall faster for many new technologies than for existing ones. This has already allowed solar-photovoltaic and onshore-wind technologies to become competitive with natural gas and coal in several locations, even without emissions taxation.

Also influential will be the emergence of new networks, such as the integration of electric-vehicle-energy storage into smart grids, as well as rapid technical progress. And these steps can be accelerated if, for example, consumers change behaviour and demand support for resource efficiency, recycling and pedestrianization. It is clear that much will depend on urban management and design; as cities grow rapidly, damaging infrastructure can become ‘locked in’.

What’s needed?

There is much that can be done to make the assumptions in standard IAMs more realistic with respect to the scale and nature of damages^{7, 4}. But to give policymakers the reliable information that they need when implementing the Paris agreement, incremental improvements^{7, 8} to the present generation of IAMs may not be enough.

A comprehensive review of the problems of using IAMs in climate economics⁵ called for the research community to develop a “third wave” of models. The authors identify various types of model that might offer advances. Two are: dynamic stochastic computable general equilibrium (DSGE) models, and agent-based models (ABMs).

Like current IAMs, DSGE models can explicitly account for uncertainty about the future through the introduction of shocks, for instance, to economic output, consumption or climate damages⁹. ABMs, by contrast, seek to provide more-realistic representations of socio-economics by simulating the economy through the interactions of a large number of different agents, on the basis of specific rules. ABMs are widely used in finance, but have yet to be seriously applied to climate change. These are promising developments.

Now, a concerted effort is required by the research community to explore as many potential avenues as possible to better estimate the costs of action and inaction on climate change. The IPCC should distil what policymakers need to inform their decision-making. Learned societies and national academies must bring together researchers from a wide range of relevant disciplines to focus attention on improving economic modelling quickly.

Bangladeshi farmers and Cairo city-dwellers are at severe risk of flooding and storms; southern Europe and parts of Africa and the Americas are threatened by desertification. Perhaps hundreds of millions of people may need to migrate as a result, posing an immense risk of conflict.

There is huge potential in future technologies that can drive change. These are omitted or badly underestimated in our current climate modelling — deeply damaging our guidance for policymaking. The well-being and prosperity of future generations are worth more.

Nature 530, 407–409 (25 February 2016) doi:10.1038/530407a

Even for folks hardened by decades in the trenches fighting climate change, the release yesterday of 2015 planetary temperature data was still shocking. The “global land and water temperature” didn’t just set another record last year, it changed the rate at which those records are being set.

This morning we downloaded the official NOAA/NCDC global temperature dataset of temperature anomalies — that’s each year’s deviation from the trend increase averaged across the 20^th Century. Here’s what we saw when we ran the stats:

• The 2015 anomaly was 0.90 degrees Celsius (1.6 degrees Fahrenheit; except for graph excerpt at right, all figures here are Celsius); in other words, last year’s global average temperature was almost a full degree above the 20^th Century average.
• The 2015 temperature anomaly was 0.16 degrees greater than the anomaly for 2014, making last year’s increase the biggest since 1997 — even though the 2014 anomaly had just set a new record.
• The trendline we drew through 1975-2015 temperature data has a nearly 4 percent steeper slope than our year-earlier trendline for 1975-2014 data. Adding 2015 data in effect lifts the prior trend from its moorings, like an earthquake, tilting it upward.

Here’s how climate scientist Michael Mann characterized the new data, as reported by the New York Times:

Michael E. Mann, a climate scientist at Pennsylvania State University, calculated that if the global climate were not warming, the odds of setting two back-to-back record years would be remote, about one chance in every 1,500 pairs of years. Given the reality that the planet is warming, the odds become far higher, about one chance in 10, according to Dr. Mann’s calculations.

(The entire Times article, which led the paper’s Jan. 21 print edition and was written by the paper’s superb climate reporter, Justin Gillis, is well worth reading.)

Here’s one more way of grasping how the rate of temperature rise is accelerating:

The trendline running through the entire 1880-2015 NOAA/NCDC dataset yields an average rate of temperature rise of 0.0668 degrees per decade; it’s probably easier to multiply that by 10 to derive a per-century rise of two-thirds of one degree. However, a trendline on just the most recent 40 years, 1975-2015, gives an average rise of 0.1664 degrees per decade, or one-and-two-thirds of one degree per century. Over the past 40 years, temperatures have risen 2.5 times as fast as they have over the entire 135-year record.

(NB: Our 1880-2015 slope matches the slope reported by NOAA/NCDC. Our choice of 1975 as the start year for our recent trendline has no particular significance; a regression on 1995-2015 yields a similar slope. For those interested in methodological issues in temperature measuring, the Niskanen Institute posted a useful primer earlier this week.)

In his State of the Union Address last week, President Obama sent a message to senators and representatives on the GOP side of the aisle:

[I]f anybody still wants to dispute the science around climate change, have at it. You will be pretty lonely, because you’ll be debating our military, most of America’s business leaders, the majority of the American people, almost the entire scientific community, and 200 nations around the world who agree it’s a problem and intend to solve it.

It’s hard to discern the extent to which the denialism running through the Republican Party is driven by ideology or by politics, especially since the two are strongly intertwined. At some point, reality will come into play. Temperature data can help that happen. So can election returns.

On Sunday, November 29, the eve of the UN climate summit in Paris, the Carbon Tax Center released a letter signed by 32 notable individuals urging Paris climate negotiators to focus on national carbon taxes, both for their intrinsic value and as a gateway to a global carbon price.

The group includes four Nobel Laureates, three former U.S. cabinet secretaries who served under four Presidents (from both major political parties), two former vice-chairs of the Federal Reserve System’s board of governors, and three distinguished faculty members from Harvard University’s economics department. It also includes leading carbon tax advocates from across the political spectrum: Jerry Taylor of the Niskanen Center, Mark Reynolds of Citizens Climate Lobby, and Charles Komanoff of CTC.

The text of the letter is directly below, followed by a complete listing of the signatories. (The identical text and listing are in this pdf.)

Released in Paris and New York, Sunday, November 29, 2015

Taxing carbon pollution will spur everyone ― businesses, consumers and policymakers ― to reduce climate-damaging emissions, invest in efficient energy systems and develop low-carbon energy sources.

This single policy change — explicitly using prices within existing markets to shift investment and behavior across all sectors — offers greater potential to combat global warming than any other policy, with minimal regulatory and enforcement costs.

We urge negotiators at the upcoming UN Climate Conference in Paris to pursue widespread implementation of national taxes on climate-damaging emissions.

We endorse these four principles for taxing carbon to fight climate change without undermining economic prosperity:

1. Carbon emissions should be taxed across fossil fuels in proportion to carbon content, with the tax imposed “upstream” in the distribution chain.

2. Carbon taxes should start low so individuals and institutions have time to adjust, but then rise substantially and briskly on a pre-set trajectory that imparts stable expectations to investors, consumers and governments.

3. Some carbon tax revenue should be used to offset unfair burdens to lower-income households.

4. Subsidies that reward extraction and use of carbon-intensive energy sources should be eliminated.

Signed,

Frank Ackerman Kenneth J. Arrow Jim Barrett Alan S. Blinder Dallas Burtraw Steven Chu Richard N. Cooper Robert H. Frank Shi-Ling Hsu Charles Komanoff N. Gregory Mankiw

Donald B. Marron Jr. Aparna Mathur Warwick McKibbin Gilbert Metcalf Adele C. Morris Robert Reich John Reilly Mark Reynolds Alice M. Rivlin James Rydge Thomas C. Schelling

Robert J. Shapiro George P. Shultz Joseph Stiglitz Steven Stoft Chad Stone Jerry Taylor Richard Thaler Eric Toder Martin Weitzman Gary Yohe

(Institutional affiliations are for identification purposes only, and do not connote any organizational approval.)

Frank Ackerman, PhD
Principal Economist, Synapse Energy Economics

Kenneth J. Arrow, PhD
Nobel Prize in Economics, 1972
Joan Kenney Professor of Economics and Professor of Operations Research, Emeritus, Stanford University
Convening Lead Author, Intergovernmental Panel on Climate Change

Jim Barrett, PhD
Chief Economist, American Council for an Energy-Efficient Economy
Former Senior Economist, Joint Economic Committee

Alan S. Blinder, PhD
Gordon S. Rentschler Memorial Professor of Economics and Public Affairs, Princeton University
Vice Chairman, Board of Governors, Federal Reserve System, 1994-1996
Member, President’s Council of Economic Advisers, 1993-1994

Dallas Burtraw, PhD
Darius Gaskins Senior Fellow, Resources for the Future

Steven Chu, PhD
Nobel Prize in Physics, 1997
U.S. Secretary of Energy, 2009-2013
Elected to Royal Society, 2014
William R. Keenan, Jr. Professor of Physics, Professor of Molecular and Cellular Physiology, Stanford University

Richard N. Cooper, PhD
Maurits C. Boas Professor of International Economics, Harvard University
Deputy Assistant Secretary of State, 1977-1981
Former Senior Staff Economist, Council of Economic Advisers

Robert H. Frank, PhD
Henrietta Johnson Louis Professor of Management, Cornell University
Professor of Economics, Samuel Curtis Johnson Graduate School of Management, Cornell University

Shi-Ling Hsu, PhD
John W. Larson Professor of Law and Associate Dean, Florida State University College of Law

Charles Komanoff
Director, Carbon Tax Center

Gregory Mankiw, PhD
Robert M. Beren Professor of Economics, Harvard University
Chair, President’s Council of Economic Advisers, 2003-2005

Donald B. Marron Jr., PhD
Director of Economic Policy Initiatives, Urban Institute
Member, President’s Council of Economic Advisers, 2008-2009
Congressional Budget Office, Deputy Director 2005-2007, Acting Director 2006

Aparna Mathur, PhD
Resident Scholar in Economic Policy Studies, American Enterprise Institute

Warwick McKibbin, PhD
Non-resident Senior Fellow, The Brookings Institution
Professor of Economics, Australian National University and Centre for Applied Macroeconomic Analysis

Gilbert Metcalf, PhD
Professor of Economics, Tufts University
Deputy Assistant Treasury Secretary for Environment and Energy, 2011-2012

Adele C. Morris, PhD
Senior Fellow and Policy Director, Climate and Energy Economics, The Brookings Institution

Robert Reich, PhD
U.S. Secretary of Labor, 1993-1997
Chancellor’s Professor of Public Policy, Goldman School of Public Policy, University of California, Berkeley

John Reilly, PhD
Co-Director, MIT Joint Program on Science and Policy of Global Change
Senior Lecturer, MIT Sloan School of Management

Mark Reynolds
Executive Director, Citizens Climate Lobby

Alice M. Rivlin, PhD
Senior Fellow, The Brookings Institution
Visiting Professor, Georgetown University
Vice Chair, Board of Governors, Federal Reserve System, 1996-1999
Director, White House Office of Management and Budget, 1994-1996
Founding Director, Congressional Budget Office, 1975-1983

James Rydge, PhD
Lead Economist, Global Commission on Economy and Climate, New Climate Economy

Thomas C. Schelling, PhD
Nobel Prize in Economics, 2005
Lucius N. Littauer Professor of Political Economy, Harvard University (Emeritus)
Professor of Foreign Policy, National Security, Nuclear Strategy and Arms Control, School of Public Policy, University of Maryland

Robert J. Shapiro, PhD
Chairman, Sonecon
Under Secretary of Commerce for Economic Affairs 1997-2001
Senior Fellow, Georgetown University School of Business

George P. Shultz, PhD
Thomas W. and Susan B. Ford Distinguished Fellow at the Hoover Institution, Stanford University
Secretary of State, 1982-1989
Secretary of the Treasury, 1972-1974
Director, White House Office of Management and Budget, 1970-1972
Secretary of Labor, 1969-1970

Joseph Stiglitz, PhD
Nobel Prize in Economics, 2001
Elected to Royal Society, 2001
John Bates Clark Medal, 1979
Professor of Economics, Columbia University
Former Senior Vice President and Chief Economist, World Bank
Chair, President’s Council of Economic Advisers, 1995-1997

Steven Stoft, PhD
Convenor, Global Carbon Pricing Symposium, Economics of Energy & Environmental Policy
Founder and Director, Global Energy Policy Center

Chad Stone, PhD
Chief Economist, Center on Budget and Policy Priorities
Council of Economic Advisers, Chief Economist 1999-2000, Senior Economist 1996-1998

Jerry Taylor
President and Founder, Niskanen Center
Vice President, Emeritus, Cato Institute
Task Force Director Emeritus for Energy, Environment and Natural Resources, American Legislative Exchange Council

Richard Thaler, PhD
Ralph and Dorothy Keller Distinguished Service Professor of Behavioral Science and Economics, Booth School of Business, University of Chicago

Eric Toder, PhD
Institute Fellow, Urban Institute
Co-director, Urban-Brookings Tax Policy Center

Martin Weitzman, PhD
Ernest E. Monrad Professor of Economics, Harvard University

Gary Yohe, PhD
Huffington Professor of Economics and Environmental Studies, Wesleyan University
Senior Member, UN Intergovernmental Panel on Climate Change

(Institutional affiliations are for identification purposes only, and do not connote any organizational approval.)