The Economic Benefits Of Carbon Fee & Dividend Policies

Introduction

Note: For charts & full text, download this PDF: Economic Benefits of Carbon Fee & Dividend white paper. To sign up for the March/April Training Series, go here.

CCL asserts that a Carbon Fee and Dividend (CFD) policy is “good for the economy and good for people,” but for some that assertion is not convincing because we are advocates for the policy.  Our advocacy would be strengthened by fully understanding and being able to relay why there is such strong support among independent experts, as reflected in the peer-reviewed economic literature, for this general type of policy. For example, why does "the largest economist’s statement in history," advocate for CFD as the best way to address climate change?

The purpose of this training is to illuminate how the peer-reviewed literature supports carbon pricing generally and CFD in particular, highlighting the literature that shows revenue neutral carbon tax (RNCT) policies provide tremendous climate and health benefits at minimal to no economic cost, and a policy as ambitious as the Energy Innovation and Carbon Dividend Act (EICDA) in particular generates net benefits to the U.S. of roughly $1 trillion a year.  Also, CFD, an RNCT policy that distributes all funds directly to households, is preferred by CCL because it provides a clear financial benefit to the most vulnerable in our society. Finally, though carbon pricing should be the backbone of an ambitious climate policy, certain regulations can be valuable complements to achieving science-based emission reduction targets.  In sum, the peer-reviewed literature shows a policy like the EICDA can quickly and efficiently help stabilize climate risk, is good for the economy, increases job opportunities, greatly improves our health, and provides a strong financial benefit to the most vulnerable.

Emission Reductions

According to scientists, temperatures will continue to rise until net emissions (emissions less carbon sinks and any carbon removal) reach zero on a global basis. Therefore, the most important thing the U.S. can do to stabilize climate risk is to pass a law that achieves net zero emissions by the 2050 target date suggested by the IPCC and to do it in a way that incentivizes other countries to follow in step.

What are the projected U.S. emission reductions from an RNCT policy?  Likely the most comprehensive study on RNCT policy impacts, referred to as the EMF 32, showed results from 11 different peer-reviewed models on a variety of such policies (see chart on page 10). Four carbon tax rates were modeled: starting at both $25/ton and $50/ton and increasing by both 1% and 5% a year. The results show significant variation in projected reductions from the models. For example, under the $50 1% policy (second column from right), after 15 years of the policy, reductions range from roughly 20% of reference scenario emissions to 50% across the 11 models.  However, all show significant reductions from a carbon price over the 15-year time frame modeled.   Note that the model with the most aggressive reductions did not report results for the $50-5% scenario, which explains the deeper maximum reductions in the $50-1% scenario. 

A recent study from Columbia University looked explicitly at what carbon price trajectory would be sufficient to achieve net zero CO₂ emissions in the U.S. by three target years: 2040, 2050 and 2060 (see chart, below).  As discussed here, the estimated price range required to meet the net zero 2050 objective is $34 to $64/ton in 2025 and $77 to $124/ton in 2030. Note that if the EICDA carbon price began in 2021, it would reach $55/ton in 2025 and $105/ton in 2030, and these are right in the middle of the range of necessary prices, so that according to this very credible estimate, the EICDA’s baseline carbon price path is well designed to achieve this science-based emission reduction target.

In sum, there is a clear consensus in the peer-reviewed economic literature that putting a price on carbon pollution will be effective in reducing emissions, and the higher the price, the more emissions will be reduced. There is some uncertainty as to just how great the reductions are, though a carbon price consistent with the baseline price within the EICDA is estimated to put the U.S. on track to achieve net zero emissions by 2050.

Longer-term GDP Impacts

A different type of model, referred to as an Integrated Assessment Model (IAM), is able to incorporate the impact of some climate and health impacts on GDP or “output” over the longer-term. Two such studies are summarized by the IMF in the October 2020 issue of World Economic Outlook (see Chapter 3). The studies, from Burke and Nordhaus, first show the impact on global GDP assuming little is done to reduce emissions. The two models generate significantly different results: whereas Burke (blue) shows Output declining by 25% by 2100, Nordhaus shows a decline of 7%. The IMF appears to favor the Burke results in stating “… more recent studies that take account of the possibility of nonlinear effects and long-lasting reductions in economic growth (for example, Burke, Hsiang, and Miguel 2015) point to much higher damages than previously projected” (Page 86).

More importantly, the models then estimate the difference in GDP should a carbon tax policy (with some initial green investment) be implemented that would reduce global emissions 80% by 2050, and the results are noteworthy (see chart, below). The Burke results show World GDP being about 10% higher (WLD in the chart below), and U.S. GDP being about 15% higher in 2100 with the carbon tax policy. Nordhaus shows weaker results, but the IMF makes clear Burke is likely more credible, stating “The more recent studies (for example, Burke, Hsiang, and Miguel 2015) point to much larger damages than previously estimated and are more in line with the substantial risks scientists have warned about the projected net output gains from mitigating climate change increase rapidly after 2050, reaching up to 13 percent of global GDP by 2100 (Figure 3.7). However, even these estimates are likely to understate benefits from mitigating climate change as they imperfectly take account of—or do not incorporate—some of the damages related to temperature increases, such as a higher frequency and severity of natural disasters, a rise in sea levels, and the risk of more catastrophic climate change.”

To summarize the impacts to GDP, when valuable climate and health benefits are not included, the impact to GDP is minimal in the shorter-term and could be slightly positive or negative. CFD tends to have a slightly negative impact on GDP, though is unique in providing significant financial benefits to low-income and minority households. In the longer term, when some of the climate benefits are included in the modeling, strong market-based climate policy significantly increases GDP.  These policies are unquestionably good for the economy, and that is why they are so fully supported by economists.

Climate and Health Benefits: Stabilizing Climate Risk

The economic value of the reduced emissions from any policy reflects the value of avoided climate damages, and these are exceedingly difficult to measure. Columbia’s Dr. Noah Kaufman recently commented to CCL that published analysis shows this value could be anywhere from $0 to $1,000 per ton of CO₂ emitted.  We first show a simple view of how certain climate damages have increased in the US.  We then look at official estimates of climate damage called the Social Cost of Carbon (SCC) in order to approximate the value of climate benefits in a policy like EICDA.

Economic damages from climate and extreme weather events, one small part of overall climate damages, are charted each year by NOAA.  The results are stunning yet should not be a surprise. The economic losses from climate and weather-related damages grew from an average of $17 billion per year in the 80s to $81 billion per year last decade, an increase of almost fivefold (471% increase). And again, inflation was completely taken out of the equation. Similarly, the number of events that cost at least $1 billion grew from an average of 2.9 per year in the 80s to 11.9 last decade, a fourfold increase. These numbers confirm our intuition: we are unquestionably seeing a steady but dramatic increase in the cost of extreme weather events. If the annual averages are taken from only the last five years of the last decade, 2015 to 2019, the average losses and events increase to $107 billion and 13.8, respectively, indicating that the trend toward increased damages may be accelerating.

How much of the increase in losses are due to climate change? We can’t know with certainty, but we can derive an indication. NOAA states that the increase is due to climate change and increased vulnerability and exposure. The increase in vulnerability and exposure reflects that there are simply more valuable assets in harm’s way in the last decade relative to the 1980s, but how much more? U.S. population growth is about one-third in that time as is the value of the average home. Though these are significant, they come nowhere near explaining a 470% increase in average annual damages. Climate change, as long predicted by a strong majority of climate scientists, is the primary driver behind this dramatic and costly trend.

The Social Cost of Carbon (SCC)

To estimate the climate benefits of a particular policy, we need an estimate of the total value of the damages avoided over time. The SCC is designed to provide exactly this (page 1): it is an estimate of the economic value of avoided damages per ton of CO₂ emissions.  The SCC is derived in two parts: the value of damages from climate change over forthcoming decades are projected with a “damage function,” and these values are discounted back using an appropriate discount rate.   

Most damage functions are quite limited in that they only include those climate impacts that we know will occur as a result of climate change and can be readily quantified. Therefore, they exclude what we cannot readily quantify or do not know will occur. The damage function may include at least portions of “mortality and other health effects from excess heat and natural disasters, depressed agricultural production, reductions in labor productivity, disruption of energy systems…property damage from hurricanes and floods” (page 2 of the above link). However, they do not include damages to ecosystems and the services they provide (e.g., natural capital), wildfires, species extinction, slower economic growth from higher temperatures, mass migration out of affected regions, increased risk of violent conflict, tipping points, morbidity, and impacts from catastrophic events. As a result of what is not included in the estimate as well as other factors, current SCC estimates significantly underestimate total damage from climate change.

As difficult as estimating the value of damages over forthcoming decades is, the challenge is compounded by the need to appropriately discount those values over time to derive a single current SCC estimate. The discount rate is incredibly impactful because the worst damages from climate change are expected to occur far into the future. As an example of its importance, whereas the discounted value of a dollar of damages in 2100 is worth 20 cents using a 3% discount rate, it is worth only nine cents using a 2% discount rate, so the discount rate used will greatly alter the SCC. 

What is a reasonable value or range of values for the SCC? Under the Obama Administration, the EPA formed an interagency working group (IWG) to derive an estimate of the SCC. An initial estimate was derived in 2013 and partially revised in 2016. The estimate was an average of results from three Integrated Assessment Models (IAM’s), utilizing scientific data generally from 2009 or before, and the resulting SCC was used by the federal government as a shadow price to ensure the cost of carbon pollution was considered in investment and purchase decisions. According to that estimate, if using a suggested constant discount rate of 3%, the SCC would be $52/ton as of 2020 and would continue to rise gradually every year.   

In 2017, the National Academy of Sciences (NAS) published an in-depth study of the SCC and how it could be improved. A consortium led by the University of Chicago, the Climate Impact Lab (CIL), set about constructing a process to generate an SCC that complied with the NAS recommendations and utilizing the latest and far more abundant climate science, utilizing more granular data and improved methodologies. Though the final estimate is not expected until the Spring of 2021, the Director of the CIL published a working paper recommending that, until the new estimate is ready, the Biden Administration use the prior IWG estimate but with a discount rate of at most 2%, owing to the fact that real (inflation adjusted) long-term risk free interest rates (i.e., yields on 10-year U.S. Treasuries) on which the discount rate may be based have declined significantly.

Very recent analysis in a top journal, as discussed here, attempts to incorporate one missing source of climate damages: those to “natural capital.” “Natural capital includes elements of nature that produce value to people either directly or indirectly.” One author provides an analogy: “The standard approach [to estimating SCC] looks at how climate change is damaging ‘the fruit of the tree’ (market goods); we are looking at how climate change is damaging the ‘tree’ itself (natural capital).” According to this analysis, just by including the “direct” damage to industries like timber, agriculture and fisheries, the total damages from climate change increase by $44/ton. Including all direct and indirect damages from impacts to natural capital increases damages by $132/ton.

From this, estimates of the climate benefits of a particular policy can be derived. The value of climate benefits in a given year are the product of the SCC and the number of tons of emissions reduced by the policy in that year. For example, using net zero by 2050 path (see Source Data, Fig. S1), the EICDA would reduce emissions by 1.5 billion tons in the 10^th year after enactment. Using $169 as our SCC, this would indicate the value of climate benefits derived in that year to be $254 billion (1.5 billion X $169).

Health Co-Benefits

Greenhouse gas emissions that cause climate change are also a significant source of air pollution that greatly degrades our health. Though climate change brings about its own health issues, such as heat stress, that are already included in the SCC estimates, health costs from air pollution are separate, and are substantial. The value of these benefits are referred to as health co-benefits of climate policy.

Though there is substantial research on health co-benefits from climate policy for both the U.S. and globally, this section is focused on the work of a team at Duke University led by Dr. Shindell. The reason is that, though work is completely in line with the literature, they focus on estimating co-benefits from a level of emission reductions consistent with the EICDA. Specifically, they evaluate U.S. health co-benefits under a policy that yields reductions consistent with a 2^oC target for global temperature increase. This allows for an explicit but conservative dollar estimate of the co-benefits from this policy.

Initial research was published on the value of U.S. health co-benefits in 2016, and they were estimated at $250 billion a year. As discussed here, Dr. Shindell presented updated research to the House Oversight Committee in August 2020 that utilized far more granular data. The revision found that over 50 years a 2^oC policy would prevent, on average, 90,000 premature deaths, 70,000 hospitalizations, and six million lost workdays each year, as well as other health benefits. The value of these benefits was estimated at an average of $700 billion per year over the 50-year period. This reflects tremendous value! In other words, we could take climate damages completely out of the equation, and the health benefits from reduced air pollution would pay for a policy like EICDA many times over.

Total Net Benefits

Clearly, the climate and health benefits of RNCT policies will greatly outweigh the costs, and this is a key reason they have nearly universal support among economists. As to the EICDA specifically, we can derive a rough but conservative estimate of net benefits: ten years after policy implementation, we conservatively estimate benefits at $952 billion ($252 $700) and costs at $98 billion for net benefits of approximately $854 billion per year. Again, this is a conservative estimate because the SCC is understated for the three reasons noted above.   

Fairness

This study from Columbia that evaluated the GDP impacts of various RNCT policies also assessed their distributional impacts, and this nicely illustrates a key reason why CCL favors returning all funds to households (CFD). They estimated the “change in tax burden” from a set of RNCT, including CFD, across income quintiles, each of which represents 20% of the population. A decline in tax burden from the policy reflects a financial benefit to the quintile. The paper makes clear that when funds are used to reduce the deficit, labor taxes, or corporate taxes, the lowest (poorest) quintiles are harmed financially as their net cost burden rises. CFD is unique in providing a clear financial benefit to the poor, and the Household Impact Study, which is specific to the EICDA, makes clear the bottom three quintiles benefit handsomely. This helps explain why, though using the funds to reduce other taxes may be slightly more beneficial to GDP, distributing the funds directly to households addresses deep economic inequities that have been growing worse in recent decades.

Job Impacts

The models that evaluate economic impacts of an RNCT policy cannot readily evaluate the economy-wide impact on employment. As a demonstration of this, none of the ten carbon pricing proposals introduced in the last Congress had an evaluation of the impact on jobs, including EICDA. The reason is that peer-reviewed analysis of these policies is done by Computable General Equilibrium (CGE) models. They start with the assumption that all markets are in equilibrium: all goods are priced so that all produced are sold, and markets “clear,” in both the non-policy (reference) scenario and in the RNCT policy scenario. Labor (the job market) is one such market: it starts at a condition of equilibrium (everyone has a job who wants one at prevailing wages) and ends at equilibrium in both non-policy and policy scenarios, so it is not useful to calculate the change in employment between the two scenarios. This makes it difficult for an assessment of job impacts within the peer-reviewed literature.   

Though we cannot readily project what the economy-wide impact on jobs will be of a specific policy, the peer-reviewed literature does tell us that job opportunities will increase significantly. First, within the energy sector, job opportunities will clearly rise. Impacts on the energy sector are critical because, in model after model, the clearest result of a carbon price is a shift from fossil fuel energy to renewables and energy efficiency. And as discussed here and here, two to five times more jobs are required to produce clean energy than to produce that energy from fossil fuels.

This research looked at the jobs created from a set dollar investment in fossil fuels versus renewables and energy efficiency. This is pertinent because the result of the carbon price will be to shift future investment. The results are similar to the production numbers above. Their summary conclusion is that “Spending a given amount of money on a clean-energy investment agenda generates approximately 3.2 times the number of jobs within the United States as does spending the same amount of money within the fossil fuel sectors” (see chart, below). The fundamental explanation for this is that, whereas fossil fuels are more “capital intensive,” requiring heavy investments in machinery and systems to extract, process and burn the fuel, clean energy is more “labor intensive,” with little or no cost for fuel, but more of the revenue supporting workers’ wages for functions such as installation, control and maintenance.

Clean Energy Jobs are Good Jobs

A concern that has stemmed from the evidence of job increases in new industries is whether they will be “good jobs” or comparable in compensation to those that they replace. A study evaluates the quality of clean energy jobs in the U.S. by comparing the wages and benefits of these jobs—clean energy generation, energy efficiency, clean grid and storage, clean fuels, and clean vehicles—to the national average as well as to those in the fossil fuel industry. The summary results are as follows:  

• Median hourly wages for clean energy jobs are 25% higher than the national median wage. Further, clean energy jobs are more likely to come with health and retirement benefits than the rest of the private sector. And generally, unionization rates for clean energy jobs are slightly higher than the rest of the private sector.
• Clean energy job salaries are comparable to fossil fuel job salaries. For instance, jobs in coal, natural gas and petroleum fuels pay about $24.37 an hour, while jobs in solar and wind pay about $24.85 an hour. Similarly, jobs in energy efficiency come with median salaries of about $24.44.
• Even without a charge for pollution, U.S. clean energy employment has grown 6.0%, more than twice the national average, for the last three years (2017-2019). In contrast, employment has fallen in the natural gas (-5.3%) and coal (-7.1%) businesses.

In summary, an RNCT will clearly cause a shift in jobs and resources from more polluting industries to cleaner industries. Though this transition must occur to stabilize climate risk, we understand the hardships that result are real and transition assistance is important. However, the evidence indicates more jobs will be created than eliminated, and that compensation in the new jobs will be comparable to the old. An RNCT will bring a stronger, cleaner economy that is a clear job creator.

A Clear Role for Regulations

Can a carbon price achieve the necessary emission reductions by itself? What role is there for regulations that complement the price? Economists agree that having an RNCT be the backbone of the policy is best for the economy and distributing the revenues to households (CFD) helps promote economic equity, but that achieving an objective as stringent as net zero by 2050 requires regulations to source reductions where a carbon price is less effective. This section first describes the key advantages of a carbon price versus regulations to motivate the vast majority of reductions. Next, the regulations are discussed that are most complementary to a carbon price, and so clearly will increase the total reductions from the policy in as efficient and effective manner as possible.

Preference for a Carbon Price - CCL believes a carbon price should be the backbone of ambitious climate policy, and economists, the IMF, World Bank, the IPCC, UN and many others agree. Below is a list of key reasons why.

• Efficiency - With an economy-wide carbon price, emission reductions are achieved in a least cost manner, so an RNCT is significantly better for the economy. A price allows producers and consumers flexibility (see section on page 12) to reduce emissions in the least-cost manner, whereas regulations tend to dictate how the reductions will be made without tapping the huge pool of expertise available throughout the private economy. So, for example, a clean energy standard (CES) in the power sector does not incentivize energy efficiency as transparently as a price does, and a fuel economy standard does not incentivize driving fewer miles or taking the bus. A study compared the impact on GDP of a CFD policy starting at just over $40/ton and rising at 5% per year to a reasonably efficient regulatory approach that generated the same level of emission reductions. The CFD policy averaged $190 billion higher GDP per year, and this figure grows over time. By 2036, the GDP was $420 billion higher, and average household consumption was $1,260 higher under the CFD policy. Arguing that climate policy is “good for the economy” is more problematic under a predominantly regulatory approach.
• Fairness – We discussed in the Fairness section, above, how CFD generally, and EICDA in particular, provides a significant financial benefit to the most vulnerable in society.  As discussed here, regulations that reduce carbon emissions tend to be neutral to slightly regressive, actually making life harder for the poor, even though those costs tend to be hidden. But more importantly, they will raise the cost of essential products like energy and energy-intensive products without any offsetting compensation and, unless the policy explicitly addresses this, it will place a financial burden on the poor and middle classes.
• Durability - CCL's objective is to help pass strong climate legislation with bipartisan support. Policy that can attract broader support stands a better chance of passage in the Senate and will provide an essential message to the global climate community that the U.S. is "in it for the long haul," allowing them to take stronger action. At this point in time, our understanding is that, as it pertains to truly ambitious climate policy, a market-based policy that does not increase national debt has the best chance of attracting Republican support.   
• Urgency - It's important that reductions begin as soon as possible. As discussed here, there is good evidence that "well-designed carbon price legislation is forecast to work very quickly, while regulatory action can be stalled for years by procedural obstacles and court challenges." There are many examples of large-scale regulatory policy initiatives that have taken years or even decades to bring to fruition. In contrast, all of the models of RNCT proposals show rapid emissions cuts occurring immediately upon enactment.
• Competitiveness and the BCA - A carbon tax increases the production costs of U.S. producers, potentially diminishing their competitiveness relative to foreign producers. A Border Carbon Adjustment (BCA) will level the playing field by reversing this charge for U.S. exporters and applying a like charge on those importing to the U.S.  This is permissible under WTO trade rules, in part because the additional cost of production owing to the environmental policy is clear. Under regulations, production costs will rise, but it's very unlikely a BCA would be compatible with regulations under WTO rules, so that the corresponding competitiveness issues cannot be readily mitigated.

Complementary Policies

So, though CCL's objectives are to pass a policy that greatly reduces emissions without burdening the most vulnerable, we and others believe it's best that carbon pricing is the backbone of ambitious climate policy. However, there are sources of emissions that a price will not quickly or efficiently mitigate and which would be better addressed with well-designed regulations, so such complementary policies should be encouraged. Columbia in a report “Interactions Between a Federal Carbon Tax and Other Climate Policies” (page 8) lists six climate policies that are "complementary" to a carbon price (left column of the chart, below), as well as several that are made somewhat or fully redundant by the carbon price. Complementary policy is defined as one that "enables more cost-effective reductions of carbon dioxide emissions than a carbon tax would achieve on its own; or reduces GHG emissions and achieves a separate policy objective more cost-effectively than a federal carbon tax would on its own." If these are enacted or strengthened, the overall policy is clearly made more effective. 

Summary

What do the independent experts, as reflected in the peer-reviewed literature, say about the impacts of an RNCT generally, and EICDA in particular?  The following are summary conclusions:

• Emissions - Carbon taxes are effective at significantly reducing emissions, and the EICDA baseline carbon price should put the U.S. on a path to achieve net zero emissions by 2050.
• GDP - When valuable climate and health benefits are not included, the impact to GDP is minimal in the shorter-term and could be slightly positive or negative.  In the longer-term, GDP is significantly enhanced by carbon tax policies.  These policies are unquestionably good for the economy, and that is why they are so fully supported by economists.
• Net Benefits – The net benefits to the economy and society, defined here as climate and health benefits less any economic cost (reduction to GDP) are substantial.  A policy like EICDA would generate nearly $1 trillion of net benefits to the U.S. each year within 10 years of enactment.
• Job Growth - Net job opportunities will grow significantly under an RNCT.  As resources shift from fossil fuels to renewables and energy efficiency, roughly three jobs will be created for every one lost.  Still, transition assistance to those in disadvantaged industries should be considered.
• Fairness - CFD is unique in providing significant financial benefits to low income and minority households.
• Role for Regulations - Finally, CCL strongly believes a carbon price should be the backbone of any ambitious U.S. climate policy.  It will be far better for the economy, is more likely to achieve bipartisan support and so be durable, and will reduce emissions more quickly once implemented.  However, certain regulations can play a very valuable complementary role, and their enactment should be encouraged.

Emission Reductions & Getting To Net Zero
(0:00)

Impact on GDP 
(45:22)

Climate & Health Benefits
(1:19:56)

Impact on Jobs 
(1:52:47)

Distribution & Fairness Concerns
(2:27:02)

Regulations & Complementary Policies 
(3:01:48)

• Jerry Hinkle (All Sections)
• Rick Knight (5th Section)
• Sara Wanous (6th Section)
• Paul Bernstein (1st Section)

Download the presentations:

• Part One: Emission Reductions & Getting To Net Zero (slides)
• Part Two: Impact on GDP (slides)
• Part Three: Climate & Health Benefits (slides) 
• Part Four: Impact on Jobs (slides)
• Part Five: Distribution & Fairness Concerns (slides) 
• Part Six: Regulations & Complementary Policies  (slides)

To skip ahead to a specific section go to the time indicated in parenthesis.

Emission Reductions & Getting To Net Zero
(0:00)

Impact on GDP 
(45:22)

Climate & Health Benefits
(1:19:56)

Impact on Jobs 
(1:52:47)

Distribution & Fairness Concerns
(2:27:02)

Regulations & Complementary Policies 
(3:01:48)

• Jerry Hinkle (All Sections)
• Rick Knight (5th Section)
• Sara Wanous (6th Section)
• Paul Bernstein (1st Section)
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• Download this episode (right click and save).
• Find the episode on CCL's iTunes channel.

• Economic Benefits of Carbon Fee & Dividend white paper PDF (to sign up for the March/April 2021 Weekly Training Series, go here)
• Climate Leadership Council: Economists Statement of Support 
• CCL Blog: Is this carbon price enough? Here’s what the experts say - Jerry Hinkle, CCL Economics Policy Network
• Columbia Center of Global Energy Policy: Net Zero Carbon Prices Two Page Summary PDF
• CCL's Research Team: 2019 Ways & Means Submitted Testimony
• Shindell, D.T. Climate and Health Impacts of US Emissions Reductions Consistent with 2 °C, Nature Climate Change, Feb 2016
• Ricke, K. et al. Country-Level Social Cost of Carbon, Nature Climate Change, Sep 24, 2018
• Goulder, L. & Hafstead, M. (2017) Confronting the Climate Challenge: US Policy Options, Resources for the Future