## US Environmental Policy (Part 1)

8 November, 2020

This blog does not allow discussion of partisan politics. But I can still list some ways in which US environmental policy will change if Biden becomes president.

First and foremost, the US will rejoin the Paris Climate Agreement.

Besides leaving the Paris Climate Agreement, the Trump administration did many other things that didn’t require approval from Congress:

• Nadja Popovich, Livia Albeck-Ripka and Kendra Pierre-Louis, The Trump administration is reversing nearly 100 environmental rules. Here’s the full list, New York Times, 15 October 2020.

Here’s the list. Biden can reverse or halt all these actions without approval from Congress:

Air pollution – completed:

1. Weakened Obama-era fuel economy and greenhouse gas standards for passenger cars and light trucks.
E.P.A. and Transportation Department
2. Revoked California’s ability to set stricter tailpipe emissions standards than the federal government.
E.P.A.
3. Withdrew the legal justification for an Obama-era rule that limited mercury emissions from coal power plants.
E.P.A.
4. Replaced the Obama-era Clean Power Plan, which would have set strict limits on carbon emissions from coal- and gas-fired power plants, with a new version that would let states set their own rules.
Executive Order; E.P.A.
5. Canceled a requirement for oil and gas companies to report methane emissions.
E.P.A.
6. Revised and partially repealed an Obama-era rule limiting methane emissions on public lands, including intentional venting and flaring from drilling operations. A federal court struck down the revision in July 2020, calling the Trump administration’s reasoning “wholly inadequate” and mandating enforcement of the original rule. However, the Obama-era rule was later partially struck down in a separate court case, during which the Trump administration declined to defend it.
Interior Department
7. Withdrew a Clinton-era rule designed to limit toxic emissions from major industrial polluters, and later proposed codifying the looser standards.
E.P.A.
8. Revised a program designed to safeguard communities from increases in pollution from new power plants to make it easier for facilities to avoid emissions regulations.
E.P.A.
9. Amended rules that govern how refineries monitor pollution in surrounding communities.
E.P.A.
10. Weakened an Obama-era rule meant to reduce air pollution in national parks and wilderness areas.
E.P.A.
11. Weakened oversight of some state plans for reducing air pollution in national parks.
E.P.A.
12. Relaxed air pollution regulations for a handful of plants that burn waste coal for electricity.
E.P.A.
13. Repealed rules meant to reduce leaking and venting of powerful greenhouse gases known as hydrofluorocarbons from large refrigeration and air conditioning systems.
E.P.A.
14. Directed agencies to stop using an Obama-era calculation of the social cost of carbon, which rulemakers used to estimate the long-term economic benefits of reducing carbon dioxide emissions.
Executive Order
15. Withdrew guidance directing federal agencies to include greenhouse gas emissions in environmental reviews. But several district courts have ruled that emissions must be included in such reviews.
Executive Order; Council on Environmental Quality
16. Revoked an Obama executive order that set a goal of cutting the federal government’s greenhouse gas emissions by 40 percent over 10 years.
Executive Order
17. Repealed a requirement that state and regional authorities track tailpipe emissions from vehicles on federal highways.
Transportation Department
18. Lifted a summertime ban on the use of E15, a gasoline blend made of 15 percent ethanol. (Burning gasoline with a higher concentration of ethanol in hot conditions increases smog.)
E.P.A.
19. Changed rules to allow states and the E.P.A. to take longer to develop and approve plans aimed at cutting methane emissions from existing landfills.
E.P.A.
20. Withdrew a proposed rule aimed at reducing pollutants, including air pollution, at sewage treatment plants.
E.P.A.
21. Relaxed some Obama-era requirements for companies to monitor and repair leaks at oil and gas facilities, including exempting certain low-production wells – a significant source of methane emissions – from the requirements altogether. (Other leak regulations were eliminated.)
E.P.A.

Air pollution – in progress:

1. Eliminated Obama-era methane emissions standards for oil and gas facilities and narrowed standards limiting the release of other polluting chemicals known as “volatile organic compounds” to only certain facilities. A federal court temporarily halted the rollback from going into effect after environmental groups and several states filed suit.
E.P.A.
2. Proposed revisions to standards for carbon dioxide emissions from new, modified and reconstructed coal power plants, eliminating Obama-era restrictions that, in effect, required them to capture and store carbon dioxide emissions.
E.P.A.
3. Began a review of emissions rules for power plant start-ups, shutdowns and malfunctions. One outcome of that review: In February 2020, E.P.A. reversed a requirement that Texas follow emissions rules during certain malfunction events.
E.P.A.
4. Proposed a rule limiting the ability of individuals and communities to challenge E.P.A.-issued pollution permits before a panel of agency judges.
E.P.A.

Drilling and extraction – completed:

1. Made significant cuts to the borders of two national monuments in Utah and recommended border and resource-management changes to several more.
Presidential Proclamation; Interior Department
2. Lifted an Obama-era freeze on new coal leases on public lands. In April 2019, a judge ruled that the Interior Department could not begin selling new leases without completing an environmental review. In February 2020, the agency published an assessment that concluded restarting federal coal leasing would have little environmental impact.
Executive Order; Interior Department
3. Finalized a plan to open up part of the Arctic National Wildlife Refuge in Alaska for oil and gas development, a move that overturns six decades of protections for the largest remaining stretch of wilderness in the United States.
Congress; Interior Department
4. Approved construction of the Dakota Access pipeline, less than a mile from the Standing Rock Sioux Reservation. (The Obama administration had halted the project, with the Army Corps of Engineers saying it would explore alternative routes.) The pipeline is embroiled in a lengthy legal battle, but has been allowed to continue operating by the Army Corps of Engineers even though a federal court reversed the Corps’ decision to allow the pipeline to run along its current path.
Executive Order; Army
5. Rescinded water pollution regulations for fracking on federal and Indian lands.
Interior Department
6. Scrapped a proposed rule that required mines to prove they could pay to clean up future pollution.
E.P.A.
7. Withdrew a requirement that Gulf oil rig owners prove they can cover the costs of removing rigs once they stop producing.
Interior Department
8. Moved the permitting process for certain projects that cross international borders, such as oil pipelines, to the office of the president from the State Department, exempting them from environmental review.
Executive Order
9. Changed how the Federal Energy Regulatory Commission considers the indirect effects of greenhouse gas emissions in environmental reviews of pipelines.
Federal Energy Regulatory Commission
10. Revoked an Obama-era executive order designed to preserve ocean, coastal and Great Lakes waters in favor of a policy focused on energy production and economic growth.
Executive Order
11. Loosened offshore drilling safety regulations implemented by the Obama after following the 2010 Deepwater Horizon explosion and oil spill, including reduced testing requirements for blowout prevention systems.
Interior Department

Drilling and extraction – in progress

1. Proposed opening most of America’s coastal waters to offshore oil and gas drilling, but delayed the plan after a federal judge in 2019 ruled that reversing a ban on drilling in the Atlantic and Arctic Oceans was unlawful. Ahead of the 2020 election, Mr. Trump announced he would exempt from drilling coastal areas around Florida, a crucial battleground state, Georgia and South Carolina.
Interior Department
2. Repealed an Obama-era rule governing royalties for oil, gas and coal leases on federal lands, which replaced a 1980s rule that critics said allowed companies to underpay the federal government. A federal judge struck down the Trump administration’s repeal, but another court froze the original rule pending litigation.
Interior Department
3. Proposed easing the approval process for oil and gas drilling in national forests by curbing the power of the Forest Service to review and approve leases, among other changes.
Agriculture Department; Interior Department
4. Withdrew proposed restrictions on mining in Bristol Bay, Alaska, despite concerns over environmental impacts on salmon habitat, including a prominent fishery. The U.S. Army Corps of Engineers has so far denied a permit for a proposed project, known as the Pebble Mine, noting it “could have substantial environmental impacts,” but left the door open for a revised plan.
E.P.A.; Army
5. Proposed revising regulations on offshore oil and gas exploration by floating vessels in the Arctic that were developed after a 2013 accident. The Interior Department previously said it was “considering full rescission or revision of this rule.”
Executive Order; Interior Department
6. Proposed opening more land for drilling in the Alaska National Petroleum Reserve, a vast swath of public land on the Arctic Ocean. The Obama administration had designated about half of the reserve as a conservation area.
Interior Department
7. Finalized a plan to allow logging and road construction in Tongass National Forest, Alaska, by exempting the area from a Clinton-era policy known as the roadless rule, which applied to much of the national forest system.
Interior Department
8. Approved the Keystone XL pipeline rejected by President Barack Obama, but a federal judge blocked the project from going forward without an adequate environmental review process. The Supreme Court in July 2020 upheld that ruling, further delaying construction of the pipeline.
Executive Order; State Department
9. Approved the use of seismic air guns for gas and oil exploration in the Atlantic Ocean. The Obama administration had denied permits for such surveys, which can kill marine life and disrupt fisheries. However, the Trump administration’s permits to allow seismic surveys expired following a protracted lawsuit, ending the possibility of seismic air gun surveys in the Atlantic in the near term. Companies would need to restart the months-long permitting process.

Infrastructure – completed:

1. Weakened the National Environmental Policy Act, one of the country’s most significant environmental laws, in order to expedite the approval of public infrastructure projects, such as roads, pipelines and telecommunications networks. The new rules shorten the time frame for completing environmental studies, limit the types of projects subject to review, and no longer require federal agencies to account for a project’s cumulative effects on the environment, such as climate change.
Council on Environmental Quality
2. Revoked Obama-era flood standards for federal infrastructure projects that required the government to account for sea level rise and other climate change effects.
Executive Order
3. Relaxed the environmental review process for federal infrastructure projects.
Executive Order
4. Overturned an Obama-era guidance that ended U.S. government financing for new coal plants overseas except in rare circumstances.
Executive Order; Treasury Department
5. Revoked a directive for federal agencies to minimize impacts on water, wildlife, land and other natural resources when approving development projects.
Executive Order
6. Revoked an Obama executive order promoting climate resilience in the northern Bering Sea region of Alaska, which withdrew local waters from oil and gas leasing and established a tribal advisory council to consult on local environmental issues.
Executive Order
7. Reversed an update to the Bureau of Land Management’s public land-use planning process.
Congress
8. Withdrew an Obama-era order to consider climate change in the management of natural resources in national parks.
National Park Service
9. Restricted most Interior Department environmental studies to one year in length and a maximum of 150 pages, citing a need to reduce paperwork.
Interior Department
10. Withdrew a number of Obama-era Interior Department climate change and conservation policies that the agency said could “burden the development or utilization of domestically produced energy resources.”
Interior Department
11. Eliminated the use of an Obama-era planning system designed to minimize harm from oil and gas activity on sensitive landscapes, such as national parks.
Interior Department
12. Withdrew Obama-era policies designed to maintain or, ideally, improve natural resources affected by federal projects.
Interior Department

Infrastructure – in progress:

1. Proposed plans to speed up the environmental review process for Forest Service projects.
Agriculture Department

Animals – completed:

1. Changed the way the Endangered Species Act is applied, making it more difficult to protect wildlife from long-term threats posed by climate change.
Interior Department; National Oceanic and Atmospheric Administration
2. Ended the automatic application of full protections for ‘threatened’ plants and animals, the classification one step below ‘endangered’ in the Endangered Species Act.
Interior Department
3. Relaxed environmental protections for salmon and smelt in California’s Central Valley in order to free up water for farmers.
Executive Order; Interior Department
4. Overturned a ban on the use of lead ammunition and fishing tackle on federal lands.
Interior Department
5. Overturned a ban on the hunting of predators in Alaskan wildlife refuges.
Congress
6. Reversed an Obama-era rule that barred using bait, such as grease-soaked doughnuts, to lure and kill grizzly bears, among other sport hunting practices that many people consider extreme, on some public lands in Alaska.
National Park Service; Interior Department
7. Amended fishing regulations to loosen restrictions on the harvest of a number of species.
8. Removed restrictions on commercial fishing in a protected marine preserve southeast of Cape Cod that is home to rare corals and a number of endangered sea animals. The Trump administration has suggested changing the management or size of two other marine protected areas in the Pacific Ocean.
Executive Order; National Oceanic and Atmospheric Administration
9. Proposed revising limits on the number of endangered marine mammals and sea turtles that can be unintentionally killed or injured with sword-fishing nets on the West Coast. (The Obama-era rules were initially withdrawn by the National Oceanic and Atmospheric Administration, but were later finalized following a court order. The agency has said it plans to revise the limits.)
10. Loosened fishing restrictions intended to reduce bycatch of Atlantic Bluefin Tuna. Nonprofits have filed a lawsuit challenging the rollback.
11. Overturned a ban on using parts of migratory birds in handicrafts made by Alaskan Natives.
Interior Department

Animals – in progress:

1. Proposed weakening critical habitat protections under the Endangered Species Act by making it easier to exclude certain areas, including for public-works projects, such as schools and hospitals, and for public lands leased to non-government businesses.
Interior Department
2. Opened nine million acres of Western land to oil and gas drilling by weakening habitat protections for the sage grouse, an imperiled bird. The Idaho District Court temporarily blocked the measure. The Montana District Court also invalidated the directive, nullifying 440 oil and gas leases, but the ruling is on hold pending appeal.
Interior Department

Water pollution – completed:

1. Scaled back pollution protections for certain tributaries and wetlands that were regulated under the Clean Water Act by the Obama administration. (A federal judge in Colorado halted implementation of the rule within the state, but it is in effect elsewhere.)
E.P.A.; Army
2. Revoked a rule that prevented coal companies from dumping mining debris into local streams.
Congress
3. Weakened a rule that aimed to limit toxic discharge from power plants into public waterways.
E.P.A.
4. Weakened a portion of the Clean Water Act to make it easier for federal agencies to issue permits for federal projects over state objections if the projects don’t meet local water quality standards, including for pipelines and other fossil fuel facilities.
Executive Order; E.P.A. holding areas, which can spill their contents because they lack a protective underlay.
E.P.A.
5. Withdrew a proposed rule requiring groundwater protections for certain uranium mines. Recently, the administration’s Nuclear Fuel Working Group proposed opening up 1,500 acres outside the Grand Canyon to nuclear production.
E.P.A.

Water pollution – in progress:

1. Proposed doubling the time allowed for utilities to remove lead pipes from water systems with high levels of lead.
E.P.A.
2. Attempted to weaken federal rules regulating the disposal and storage of coal ash waste from power plants, but a court determined the original rules were already insufficient to protect the environment. The E.P.A. then proposed a new rule that would allow unlined coal ash ponds, previously deemed unsafe, to continue operating.
E.P.A.
3. Proposed a regulation limiting the scope of an Obama-era rule under which companies had to prove that large deposits of recycled coal ash would not harm the environment.
E.P.A.

Toxic substances and safety – completed:

1. Rejected a proposed ban on chlorpyrifos, a pesticide linked to developmental disabilities in children. In 2020, the E.P.A. also rejected its own earlier finding that the pesticide can cause serious health problems. (Several states have banned use of the pesticide and its main manufacturer said it would stop producing the product because of shrinking demand.)
E.P.A.
2. Narrowed the scope of a 2016 law mandating safety assessments for potentially toxic chemicals like dry-cleaning solvents. The updated rules allowed the E.P.A. to exclude some chemical uses and types of exposure in the review process. In November 2019, a court of appeals ruled the agency must widen its scope to consider full exposure risks, but watchdog groups say the agency has not done so in some assessments.
E.P.A.
3. Reversed an Obama-era rule that required braking system upgrades for “high hazard” trains hauling flammable liquids like oil and ethanol.
Transportation Department
4. Changed safety rules to allow for rail transport of highly flammable liquefied natural gas.
Transportation Department

Toxic substances and safety – in progress:

1. Proposed limiting pesticide application buffer zones that are intended to protect farmworkers and bystanders from accidental exposure.
E.P.A.
2. Announced a review of an Obama-era rule lowering coal dust limits in mines. The head of the Mine Safety and Health Administration said there were no immediate plans to change the dust limit but has extended a public comment period until 2022.
Labor Department

Other – completed:

1. Repealed an Obama-era regulation that would have nearly doubled the number of light bulbs subject to energy-efficiency standards starting in January 2020. The Energy Department also blocked the next phase of efficiency standards for general-purpose bulbs already subject to regulation.
Energy Department
2. Changed a 25-year-old policy to allow coastal replenishment projects to use sand from protected ecosystems.
Interior Department
3. Limited funding of environmental and community development projects through corporate settlements of federal lawsuits.
Justice Department
4. Stopped payments to the Green Climate Fund, a United Nations program to help poorer countries reduce carbon emissions.
Executive Order
5. Reversed restrictions on the sale of plastic water bottles in national parks desgined to cut down on litter, despite a Park Service report that the effort worked.
Interior Department

Other – in progress:

1. Proposed limiting the studies used by the E.P.A. for rulemaking to only those that make data publicly available. (Scientists widely criticized the proposal, saying it would effectively block the agency from considering landmark research that relies on confidential health data.)
E.P.A.
2. Proposed changes to the way cost-benefit analyses are conducted under the Clean Air Act. Similar rules for the Clean Water Act and other environmental statutes are in development.
E.P.A.
3. Proposed freezing efficiency standards for residential furnaces and commercial water heaters designed to reduce energy use.
Energy Department
4. Created a product category that would allow some dishwashers to be exempt from energy efficiency standards.
Energy Department
5. Initially withdrew, and then delayed, a proposed rule that would inform car owners about fuel-efficient replacement tires.
Transportation Department

## Electric Cars

24 September, 2020

Some good news! According to this article, we’re rapidly approaching the tipping point when, even without subsidies, it will be as cheaper to own an electric car than one that burns fossil fuels.

• Jack Ewing, The age of electric cars is dawning ahead of schedule, New York Times, September 20, 2020.

FRANKFURT — An electric Volkswagen ID.3 for the same price as a Golf. A Tesla Model 3 that costs as much as a BMW 3 Series. A Renault Zoe electric subcompact whose monthly lease payment might equal a nice dinner for two in Paris.

As car sales collapsed in Europe because of the pandemic, one category grew rapidly: electric vehicles. One reason is that purchase prices in Europe are coming tantalizingly close to the prices for cars with gasoline or diesel engines.

At the moment this near parity is possible only with government subsidies that, depending on the country, can cut more than \$10,000 from the final price. Carmakers are offering deals on electric cars to meet stricter European Union regulations on carbon dioxide emissions. In Germany, an electric Renault Zoe can be leased for 139 euros a month, or \$164.

Electric vehicles are not yet as popular in the United States, largely because government incentives are less generous. Battery-powered cars account for about 2 percent of new car sales in America, while in Europe the market share is approaching 5 percent. Including hybrids, the share rises to nearly 9 percent in Europe, according to Matthias Schmidt, an independent analyst in Berlin.

As electric cars become more mainstream, the automobile industry is rapidly approaching the tipping point when, even without subsidies, it will be as cheap, and maybe cheaper, to own a plug-in vehicle than one that burns fossil fuels. The carmaker that reaches price parity first may be positioned to dominate the segment.

A few years ago, industry experts expected 2025 would be the turning point. But technology is advancing faster than expected, and could be poised for a quantum leap. Elon Musk is expected to announce a breakthrough at Tesla’s “Battery Day” event on Tuesday that would allow electric cars to travel significantly farther without adding weight.

The balance of power in the auto industry may depend on which carmaker, electronics company or start-up succeeds in squeezing the most power per pound into a battery, what’s known as energy density. A battery with high energy density is inherently cheaper because it requires fewer raw materials and less weight to deliver the same range.

“We’re seeing energy density increase faster than ever before,” said Milan Thakore, a senior research analyst at Wood Mackenzie, an energy consultant which recently pushed its prediction of the tipping point ahead by a year, to 2024.

However, the article also points out that this tipping point is of the overall lifetime cost of the vehicle! The sticker price of electric cars will still be higher for a while. And there aren’t nearly enough charging stations!

My next car will be electric. But first I’m installing solar power for my house. I’m working on it now.

## Can We Fix The Air?

12 January, 2020

I published a slightly different version of this article in Nautilus on November 28, 2019.

Water rushes into Venice’s city council chamber just minutes after the local government rejects measures to combat climate change. Wildfires consume eastern Australia as fire danger soars past “severe” and “extreme” to “catastrophic” in parts of New South Wales. Ice levels in the Chukchi Sea, north of Alaska, hit record lows. England sees floods all across the country. And that’s just this week, as I write this.

Human-caused climate change, and the disasters it brings, are here. In fact, they’re just getting started. What will things be like in another decade, or century?

It depends on what we do. If our goal is to stop global warming, the best way is to cut carbon emissions now—to zero. The United Kingdom, Denmark, and Norway have passed laws requiring net zero emissions by 2050. Sweden is aiming at 2045. But the biggest emitters—China, the United States, and India—are dragging their heels. So to keep global warming below 2 degrees Celsius over pre-industrial levels by 2100, it’s becoming more and more likely that we’ll need negative carbon emissions:

That is, we’ll need to fix the air. We’ll need to suck more carbon dioxide out of the atmosphere than we put in.

This may seem like a laughably ambitious goal. Can we actually do it? Or is it just a fantasy? I want to give you a sense of what it would take. But first, here’s one reason this matters. Most people don’t realize that large negative carbon emissions are assumed in many of the more optimistic climate scenarios. Even some policymakers tasked with dealing with climate change don’t know this.

In 2016, climate scientists Kevin Anderson and Glen Peters published a paper on this topic, called “The trouble with negative emissions.” The title is a bit misleading, since they are not against negative emissions. They are against lulling ourselves into complacency by making plans that rely on negative emissions—because we don’t really know how to achieve them at the necessary scale. We could be caught in a serious bind, with the poorest among us taking the biggest hit.

So, how much negative carbon emissions do we need to stay below 2 degrees Celsius of warming, and how people are hoping to achieve them? Let’s dive in!

In 2018, humans put about 37 billion tonnes of carbon dioxide into the air. A “tonne” is a metric ton, a bit larger than a US ton. Since the oxygen is not the problem—carbon dioxide consisting of one atom of carbon and two of oxygen—it might make more sense to count tonnes of carbon. But it’s customary to keep track of carbon by its carbon dioxide equivalent, so I’ll do that here. The National Academy of Sciences says that to keep global warming below 2 degrees Celsius by the century’s end, we will probably need to be removing about 10 billion tonnes of carbon dioxide from the air each year by 2050, and double that by 2100. How could we do this?

Whenever I talk about this, I get suggestions. Many ignore the sheer scale of the problem. For example, a company called Climeworks is building machines that suck carbon dioxide out of the air using a chemical process. They’re hoping to use these gadgets to make carbonated water for soft drinks—or create greenhouses that have lots of carbon dioxide in the air, for tastier vegetables. This sounds very exciting…until you learn that currently their method of getting carbon dioxide costs about \$500 per ton. It’s much cheaper to make the stuff in other ways; beverage-grade carbon dioxide costs about a fifth as much. But even if they bring down the price and become competitive in their chosen markets, greenhouses and carbonation use only 6 million tonnes of carbon dioxide annually. This is puny compared to the amount we need to remove.

Thus, the right way to think of Climeworks is as a tentative first step toward a technology that might someday be useful for fighting global warming—but only if it can be dramatically scaled up and made much cheaper. The idea of finding commercial uses for carbon dioxide as a stepping-stone, a way to start developing technologies and bringing prices down, is attractive. But it’s different from finding commercial uses that could make a serious dent in our carbon emissions problem.

Here’s another example: using carbon dioxide from the air to make plastics. There’s a company called RenewCO2 that wants to do this. But even ignoring the cost, it’s clear that such a scheme could remove 10 billion tonnes of carbon dioxide from the air each year only if we drastically ramped up our production of plastics. In 2018, we made about 360 million tonnes of plastic. So, we’d have to boost plastic production almost ten-fold. Furthermore, we’d have to make all this plastic without massively increasing our use of fossil fuels. And that’s a general issue with schemes to fix the air. If we could generate a huge abundance of power in a carbon-free way—say from nuclear, solar, or wind—we could use some of that power to remove carbon dioxide from the atmosphere. But for the short term, a better use of that power is to retire carbon-burning power plants. Thus, while we can dream about energy-intensive methods of fixing the air, they will only come into their own—if ever—later in the century.

If plastics aren’t big enough to eat up 10 billion tonnes of carbon dioxide per year, what comes closer? Agriculture. I’m having trouble finding the latest data, but in 2004 the world created roughly 5 billion tonnes of “crop residue”: stems, leaves, and such left over from growing food. If we could dispose of most of this residue in a way that would sequester the carbon, that would count as serious progress. Indeed, environmental engineer Stuart Strand and physicist Gregory Benford—also a noted science fiction writer—have teamed up to study what would happen if we dumped bales of crop residue on the ocean floor. Even though this stuff would rot, it seems that the gases produced will take hundreds of years to resurface. And there’s plenty of room on the ocean floor.

Short of a massive operation to sink crop residues to the bottom of the sea, there are still many other ways to improve agriculture so that the soil accumulates more carbon. For example, tilling the land less reduces the rate at which organic matter decays and carbon goes back into the air. You can actually fertilize the land with half-burnt plant material full of carbon, called “biochar.” Planting crops with bigger roots, or switching from annual crops to perennials, also helps. These are just a few of the good ideas people have had. While agriculture and soil science are complex, and you probably don’t want to get into the weeds on this, the National Academy of Sciences estimates that we could draw down 3 billion tonnes of carbon dioxide per year from improved agriculture. That’s huge.

Having mentioned agriculture, it’s time to talk about forests. Everyone loves trees. However, it’s worth noting that a mature forest doesn’t keep on pulling down carbon at a substantial rate forever. Yes, carbon from the air goes to form wood and organic material in the soil. But decaying wood and organic material releases carbon back into the air. A climax forest is close to a steady state: the rate at which it removes carbon from the air is roughly equal to the rate at which it releases this carbon. So, the time when a forest pulls down the most carbon is when it’s first growing.

In July 2019, a paper in Science argued that the Earth has room for almost 4 million square miles of new forests. The authors claimed that as these new trees grow, they could pull down about 730 billion tonnes of carbon dioxide.

At first this sounds great. But remember, we are putting out 37 billion tonnes a year. So, the claim is that if we plant new forests over an area somewhat larger than the US, they will absorb the equivalent of roughly 20 years of carbon emissions. In short, this heroic endeavor would buy us time, but it wouldn’t be a permanent solution. Worse, many other authors have argued that the Science paper was overly optimistic. One rebuttal points out that it mistakenly assumed treeless areas have no organic carbon in the soil already. It also counted on a large increase of forests in regions that are now grassland or savanna. With such corrections made, it’s possible that new forests could only pull down at most 150 billion tonnes of carbon dioxide.

That’s still a lot. But getting people to plant vast new forests will be hard. Working with more realistic assumptions, the National Academy of Sciences says that in the short term we could draw down 2.5 billion tonnes of carbon dioxide per year by planting new forests and better managing existing ones. In short: If we push really hard, better agriculture and forestry could pull 5.5 billion tonnes of carbon dioxide from the air each year. One great advantage of both these methods is that they harness the marvelous ability of plants to turn carbon dioxide into complex organic compounds in a solar-powered way—much better than any technology humans have devised so far. If we ever invent new technologies that do better, it’ll probably be because we’ve learned some tricks from our green friends.

And here’s another way plants can help: biofuels. If we burn fuels that come from plants, we’re taking carbon out of the atmosphere and putting it right back in: net zero carbon emissions, roughly speaking. That’s better than fossil fuels, where we dig carbon up from the ground and burn it. But it would be even better if we could burn plants as fuels but then capture the carbon dioxide, compress it, and pump it underground into depleted oil and gas fields, unmineable coal seams, and the like.

To do this, we probably shouldn’t cut down forests to clear space for crops that we burn. Turning corn into ethanol is also rather inefficient, though the corn lobby in the U.S. has persuaded the government to spend lots of money on this, and about 40 percent of all corn grown in the U.S. now gets used this way. Suppose we just took all available agricultural, forestry, and municipal waste, like lawn trimmings, food waste, and such, to facilities able to burn it and pump the carbon dioxide underground. All this stuff ultimately comes from plants sucking carbon from the air. So, how much carbon dioxide could we pull out of the atmosphere this way? The National Academy of Sciences says up to 5.2 billion tonnes per year.

Of course, we can’t do this and also sink all agricultural waste into the ocean—that’s just another way of dealing with the same stuff. Furthermore, this high-end figure would require immensely better organization than we’ve been able to achieve so far. And there are risks involved in pumping lots of carbon dioxide underground.

What other activities could draw down lots of carbon? It pays to look at the biggest human industries: biggest, that is, in terms of sheer mass being processed. For example, we make lots of cement. Global cement production in 2017 was about 4.5 billion tons, with China making more than the rest of the world combined, and a large uncertainty in how much they made. As far as I know, only digging up and burning carbon is bigger: for example, 7.7 billion tons of coal is being mined per year.

Right now cement is part of the problem: To make the most commonly used kind we heat limestone until it releases carbon dioxide and becomes “quicklime.” Only about 7 percent of the total carbon we emit worldwide comes from this process—but that still counts for more than the entire aviation industry. Some scientists have invented cement that absorbs carbon dioxide as it dries. It has not yet caught on commercially, but the pressure on the industry is increasing. If we could somehow replace cement with a substance made mostly of carbon pulled from the atmosphere, and do it in an economically viable way, that would be huge. But this takes us into the realm of technologies that haven’t been invented yet.

New technologies may in fact hold the key to the problem. In the second half of the century we should be doing things that we can’t even dream of yet. In the next century, even more so. But it takes time to perfect and scale up new technologies. So it makes sense to barrel ahead with what we can do now, then shift gears as other methods become practical. Merely waiting and hoping is not wise.

Totaling up some of the options I’ve listed, we could draw down 1 billion tonnes of carbon dioxide by planting trees, 1.5 billion by better forest management, 3 billion by better agricultural practices, and up to 5.2 billion by biofuels with carbon capture. This adds up to over 10 billion tonnes per year. It’s not nearly enough to cancel the 37 billion tonnes we’re dumping into the air each year now. But combined with strenuous efforts to cut emissions, we might squeak by, and keep global warming below 2 degrees Celsius.

Even if we try, we are far from guaranteed to succeed—Anderson and Peters are right to warn about this. But will we even try? This is more a matter of politics and economics than of science and technology. The engineer Saul Griffith said that dealing with global warming is not like the Manhattan Project—it’s like the whole of World War II but with everyone on the same side. He was half right: We are not all on the same side. Not yet, anyway. Getting leaders who are inspired by these huge challenges, rather than burying their heads in the sand, would be a big step in the right direction.

## How to Solve Climate Change

28 December, 2019

Happy New Year!

This podcast of an interview with Saul Griffith is a great way to start your year:

• Ezra Klein, How to solve climate change and make life more awesome.

Skip straight down to the bottom and listen to the interview! Or right click on the link below and

I usually prefer reading stuff, but this is only available in audio form—and it’s worth it.

One important thing he says:

We have not had anyone stand up and espouse a vision of the future that could sound like success.

I think it’s time to start doing that. I think I’m finally figuring out how. But this interview with Saul Griffith does it already!

## Climate Technology Primer (Part 2)

13 October, 2019

Here’s the second of a series of blog articles:

• Adam Marblestone, Climate technology primer (2/3): CO2 removal.

The first covered the basics of climate science as related to global warming. This one moves on to consider technologies for removing carbon dioxide from the air.

I hope you keep the following warning in mind as you read on:

I’m focused here on trying to understand the narrowly technical aspects, not on the political aspects, despite those being crucial. This is meant to be a review of the technical literature, not a political statement. I worried that writing a blog purely on the topic of technological intervention in the climate, without attempting or claiming to do justice to the social issues raised, would implicitly suggest that I advocate a narrowly technocratic or unilateral approach, which is not my intention. By focusing on technology, I don’t mean to detract from the importance of the social and policy aspects.

The technological issues are worth studying on their own, since they constrain what’s possible. For example: to draw down as much CO2 as human civilization is emitting now, with trees their peak growth phase and their carbon stored permanently, could be done by covering the whole USA with such trees.

## Climate Technology Primer (Part 1)

5 October, 2019

Here’s the first of a series of blog articles on how technology can help address climate change:

• Adam Marblestone, Climate technology primer (1/3): basics.

Adam Marblestone is a research scientist at Google DeepMind studying connections between neuroscience and artificial intelligence. Previously, he was Chief Strategy Officer of the brain-computer interface company Kernel, and a research scientist in Ed Boyden’s Synthetic Neurobiology Group at MIT working to develop new technologies for brain circuit mapping. He also helped to start companies like BioBright, and advised foundations such as the Open Philanthropy Project.

Now, like many of us, he’s thinking about climate change, and what to do about it. He writes:

In this first of three posts, I attempt an outsider’s summary of the basic physics/chemistry/biology of the climate system, focused on back of the envelope calculations where possible. At the end, I comment a bit about technological approaches for emissions reductions. Future posts will include a review of the science behind negative emissions technologies, as well as the science (with plenty of caveats, don’t worry) behind more controversial potential solar radiation management approaches. This first post should be very basic for anyone “in the know” about energy, but I wanted to cover the basics before jumping into carbon sequestration technologies.

Check it out! I like the focus on “back of the envelope” calculations because they serve as useful sanity checks for more complicated models… and also provide a useful vaccination against the common denialist argument “all the predictions rely on complicated computer models that could be completely wrong, so why should I believe them?” It’s a sad fact that one of the things we need to do is make sure most technically literate people have a basic understanding of climate science, to help provide ‘herd immunity’ to everyone else.

The ultimate goal here, though, is to think about “what can technology do about climate change?”

## Divesting

18 September, 2019

Christian Williams

John always tells me to write short, sweet, and clear. Knowing that his advice is supreme on these matters, I’ll try to write mini-posts in between the bigger ones. But… not this time – the topic is too good.

…..

Work smarter, not (just) harder.

Today I got an email from Bill McKibben, founder of 350.org. (350 parts per million, the concentration of CO2 considered a “safe upper limit” for Earth, by NASA scientists James Hansen. We’re soaring past 415ppm.) In preparation for the global climate strike, Bill wants to share an important idea: divesting from fossil fuels may be our greatest lever.

Money is the Oxygen on which the Fire of Global Warming Burns

I’ll pluck paragraphs to quote, but please read the whole article; this is an extremely important and practical idea for addressing the crisis. And it’s well written… the first sentence sounds fairly Baezian.

I’m skilled at eluding the fetal crouch of despair—because I’ve been working on climate change for thirty years, I’ve learned to parcel out my angst, to keep my distress under control. But, in the past few months, I’ve more often found myself awake at night with true fear-for-your-kids anguish. This spring, we set another high mark for carbon dioxide in the atmosphere: four hundred and fifteen parts per million, higher than it has been in many millions of years. The summer began with the hottest June ever recorded, and then July became the hottest month ever recorded. The United Kingdom, France, and Germany, which have some of the world’s oldest weather records, all hit new high temperatures, and then the heat moved north, until most of Greenland was melting and immense Siberian wildfires were sending great clouds of carbon skyward. At the beginning of September, Hurricane Dorian stalled above the Bahamas, where it unleashed what one meteorologist called “the longest siege of violent, destructive weather ever observed” on our planet.

Bill emphasizes that change has moved far too slowly, of course. But he’s spent the past week with Greta Thunberg and many other activists, and one can tell that he really is heartened.

It seems that there are finally enough people to make an impact… what if there were an additional lever to pull, one that could work both quickly and globally?

Today it is large corporations which have the greatest power over daily life, and they are far more susceptible to pressure and change then the insulated bureaucracies of governments.

Thankfully Bill and many others knew this years ago, and started a divestment campaign of breathtaking magnitude:

Seven years ago, 350.org helped launch a global movement to persuade the managers of college endowments, pension funds, and other large pots of money to sell their stock in fossil-fuel companies. It has become the largest such campaign in history: funds worth more than eleven trillion dollars have divested some or all of their fossil-fuel holdings.

And it has been effective: when Peabody Energy, the largest American coal company, filed for bankruptcy, in 2016, it cited divestment as one of the pressures weighing on its business, and, this year, Shell called divestment a “material adverse effect” on its performance.

The movement is only growing, accelerating, and setting its sights on the big gorillas. The main sectors: banking, asset management, and insurance.

Consider a bank like, say, JPMorgan Chase, which is America’s largest bank and the world’s most valuable by market capitalization. In the three years since the end of the Paris climate talks, Chase has reportedly committed 196 billion dollars in financing for the fossil-fuel industry, much of it to fund extreme new ventures: ultra-deep-sea drilling, Arctic oil extraction, and so on. In each of those years, ExxonMobil, by contrast, spent less than 3 billion dollars on exploration, research, and development. \$196B is larger than the market value of BP; it dwarfs that of the coal companies or the frackers. By this measure, Jamie Dimon, the C.E.O. of JPMorgan Chase, is an oil, coal, and gas baron almost without peer.

But here’s the thing: fossil-fuel financing accounts for only about 7% of Chase’s lending and underwriting. The bank lends to everyone else, too—to people who build bowling alleys and beach houses and breweries. And, if the world were to switch decisively to solar and wind power, Chase would lend to renewable-energy companies, too. Indeed, it already does, though on a much smaller scale… It’s possible to imagine these industries, given that the world is now in existential danger, quickly jettisoning their fossil-fuel business. It’s not easy to imagine—capitalism is not noted for surrendering sources of revenue. But, then, the Arctic ice sheet is not noted for melting.

Bill elucidates the fact that it is critical to effect the divestment of giants like Chase, Blackrock, and Chubb. Even if these targets are quite hard, this method of action applies to every aspect of the economy, and empowers every single individual (more below). If the total divestment is spread over a decade, it can be done without serious economic instability. And if done well, it will spur tremendous growth in the renewable energy sector and ecological economy in general, as public consciousness opens up to these ideas on a large scale.

I want to keep giving quotes, but you can read it. (If anyone is out of free articles for New Yorker, I can send a text file.) I’ll contribute a few of my own thoughts, expanding on stuff implicit in the article; and then this topic can be continued with another post.

…..

Divesting is a truly powerful lever, for several reasons.

First, money talks. Many people who have been misled by modern society have the following equation in their heads:

money = value

These people, being overwhelmed with social complexity, have lifted the “burden” of large-scale ethics off of their shoulders and into a blind faith in the economic system – thinking “well, if enough people have the right idea, then capitalism will surely head in the right direction.”

Of course, after not too long, we find that this is not the case. But their thinking has not changed, and we need a way to communicate with them. While it may feel strange and wrong to reformulate the message from “ethical imperative” to “financial risk”, this is the way to get through to many people in powerful places. When you read about success stories, it is effective, especially considering all the time spent mired in anthropogenic-warming skepticism.

Second, social pressure is now a real force in the world. We can bend competition to our will: incentivize companies to better practices, and when one capitulates, the others in that sphere follow. It has happened many times, and the current is only getting stronger.

Though if we want to fry bigger fish than no-straws, we need to sharpen our collective tactics. It will of course be more systematic and penetrating than shaming companies on Twitter. The article includes great examples of this; it would be awesome to discuss more ideas in the comments.

Third, everyone can help this way, directly and significantly. Everyone has a bank account. It is not difficult, nor seriously detrimental, to switch to a credit union. The divestment campaign can be significantly accelerated by a movement of concerned citizens making this transition.

(My family uses Chase. When I was spending quality time back home, I asked my parents how the value of a bank is anything more than secure money storage. The main thing they mentioned was loans – but they admitted that the biggest and best loan they ever took was through a credit union. The reasons simply did not add up. I plan to show them this article, and I’ll try to have an earnest conversation with them. I really hope they understand, because I know they are rational and good people.)

It’s all but impossible for most of us to stop using fossil fuels immediately, especially since, in many places, the fossil-fuel and utility industries have made it difficult and expensive to install solar panels on your roof. But it’s both simple and powerful to switch your bank account: local credit unions and small-town banks are unlikely to be invested in fossil fuels, and Beneficial State Bank and Amalgamated Bank bring fossil-free services to the West and East Coasts, respectively, while Aspiration Bank offers them online. (And they’re all connected to A.T.M.s.)

This all could, in fact, become one of the final great campaigns of the climate movement—a way to focus the concerted power of any person, city, and institution with a bank account, a retirement fund, or an insurance policy on the handful of institutions that could actually change the game. We are indeed in a climate moment—people’s fear is turning into anger, and that anger could turn fast and hard on the financiers. If it did, it wouldn’t end the climate crisis: we still have to pass the laws that would actually cut the emissions, and build out the wind farms and solar panels. Financial institutions can help with that work, but their main usefulness lies in helping to break the power of the fossil-fuel companies.

…..

The economy is far more responsive to changes in the collective ethos than the government. This is how people can directly express their values every day, with every bit of earning they have. We are recognizing that the public mindset is changing, and we can now take heart and leverage society in the right direction.

Conjecture The critical science of our time has the form:

$Ecology$
$\Uparrow \;\;\;\;\; \Downarrow$
$Economy$

This is why John Baez brought together so many capable people for the Azimuth Project. I hope that we can connect with the new momentum and coordinate on something great. Even in just the last post there were some really good ideas. I really look forward to hearing more. Thanks.

## UN Climate Action Summit

4 September, 2019

Christian Williams

Hello, I’m Christian Williams. I study category theory with John Baez at UC Riverside. I’ve written two posts on Azimuth about promising distributed computing endeavors. I believe in the power of applied theory – that’s why I left my life in Texas just to work with John. But lately I’ve begun to wonder if these great ideas will help the world quickly enough.

I want to discuss the big picture, and John has kindly granted me this platform with such a diverse, intelligent, and caring audience. This will be a learning process. All thoughts are welcome. Thanks for reading.

…..
I am the master of my fate,
I am the captain of my soul.

It’s important to be positive. Humanity now has a global organization called the United Nations. Just a few years ago, members signed an amazing treaty called The Paris Agreement. The parties and signatories:

… basically everyone.

By ratifying this document, the nations of the world agreed to act to keep global warming below 2C above pre-industrial levels – an unparalleled environmental consensus. (On Azimuth, in 2015.) It’s not mandatory, and to me that’s not the point. Together we formally recognize the crisis and express the intent to turn it around.

Except… we really don’t have much time.

We are consistently finding that the ecological crisis is of a greater magnitude and urgency than we thought. The report that finally slapped me awake is the IPCC 2018, which explains the difference between 2C and 1.5C in terms of total devastation and lives, and states definitively:

We must reduce global carbon emissions by 45% by 2030, and by 100% by 2050 to keep within 1.5C. We must have strong negative emissions into the next century. We must go well beyond our agreement, now.

So… how is our progress on the agreement? That is complicated, and a whole analysis is yet to be done. Here is the UN progress tracker. Here is an NRDC summary. Some countries are taking significant action, but most are not yet doing enough. Let that sink in.

However, the picture is much deeper than only national. Reform sparks at all levels of society: a US politician wanting to leave the agreement emboldened us to form the vast coalition We Are Still In. There are many initiatives like this, hundreds of millions of people rising to the challenge. A small selection:

Each of us must face this challenge, in their own way.

…..

Responding to the findings of the IPCC, the UN is meeting in New York on September 23, with even higher ambitions and higher stakes: UN Climate Action Summit 2019. The leaders will not sit around and give pep talks. They are developing plans which will describe how to transform society.

On the national level, we must make concrete, compulsory commitments. If they do not soon then we must demand louder, or take their place. The same week as the summit, there will be a global climate strike. It is crucial that all generations join the youth in these demonstrations.

We must change how the world works. We have reached global awareness, and we have reached an ethical imperative.

## Carbon Offsets

15 August, 2019

A quick question: if somebody wants to donate money to reduce his or her carbon footprint, which org(s) would you recommend that he or she donate to?

Do you have a good answer to this? I don’t want answers that deny the premise. We’re assuming someone wants to donate money to reduce his or her carbon footprint, and choosing an organization based on this. We’re not comparing this against other activities, like cutting personal carbon emissions or voting for politicians who want to cut carbon emissions.

Here’s my best answer so far:

The Gold Standard Foundation is one organization that tackles my friend’s question. See for example:

• Gold Standard, Offset your emissions.

Here they list various ways to offset your carbon emissions, currently with prices between \$11 and \$18 per tonne.

The Gold Standard Foundation is a non-profit foundation headquartered in Geneva that tries to ensure that carbon credits are real and verifiable and that projects make measurable contributions to sustainable development.

## Negative Carbon Emissions

2 March, 2019

A carbon dioxide scrubber is any sort of gadget that removes carbon dioxide from the air. There are various ways such gadgets can work, and various things we can do with them. For example, they’re already being used to clean the air in submarines and human-occupied spacecraft. I want to talk about carbon dioxide scrubbers as a way to reduce carbon emissions from burning fossil fuels, and a specific technology for doing this. But I don’t want to talk about those things today.

Why not? It turns out that if you start talking about the specifics of one particular approach to fighting global warming, people instantly want to start talking about other approaches they consider better. This makes some sense: it’s a big problem and we need to compare different approaches. But it’s also a bit frustrating: we need to study different approaches individually so we can know enough to compare them, or make progress on any one approach.

I mainly want to study the nitty-gritty details of various individual approaches, starting with one approach to carbon scrubbing. But if I don’t say anything about the bigger picture, people will be unsatisfied.

So, right now I want to say a bit about carbon dioxide scrubbers.

The first thing to realize—and this applies to all approaches to battling global warming—is the huge scale of the task. In 2018 we put 37.1 gigatonnes of CO2 into the atmosphere by burning fossil fuels and making cement.

That’s a lot! Let’s compare some of the other biggest human industries, in terms of the sheer mass being processed.

Cement production is big. Global cement production in 2017 was about 4.1 gigatonnes, with China making more than the rest of the world combined, and a large uncertainty in how much they made. But digging up and burning carbon is even bigger. For example, over 7 gigatonnes of coal is being mined per year. I can’t find figures on total agricultural production, but in 2004 we created about 5 gigatonnes of agricultural waste. Total grain production was just 2.53 gigatonnes in 2017. Total plastic production in 2017 was a mere 348 megatonnes.

So, to use technology to remove as much CO2 from the air as we’re currently putting in would require an industry that processes more mass than any other today.

I conclude that this won’t happen anytime soon. Indeed David McKay calls all methods of removing CO2 from air “the last thing we should talk about”. For now, he argues, we should focus on cutting carbon emissions. And I believe that to do that on a large enough scale requires economic incentives, for example a carbon tax.

But to keep global warming below 2°C over pre-industrial levels, it’s becoming increasingly likely that we’ll need negative carbon emissions:

Indeed, a lot of scenarios contemplated by policymakers involve net negative carbon emissions. Often they don’t realize just how hard these are to achieve! In his talk Mitigation on methadone: how negative emissions lock in our high-carbon addiction, Kevin Anderson has persuasively argued that policymakers are fooling themselves into thinking we can keep burning carbon as we like now and achieve the necessary negative emissions later. He’s not against negative carbon emissions. He’s against using vague fantasies of negative carbon emissions to put off confronting reality!

It is not well understood by policy makers, or indeed many academics, that IAMs [integrated assessment models] assume such a massive deployment of negative emission technologies. Yet when it comes to the more stringent Paris obligations, studies suggest that it is not possible to reach 1.5°C with a 50% chance without significant negative emissions. Even for 2°C, very few scenarios have explored mitigation without negative emissions, and contrary to common perception, negative emissions are also prevalent in higher stabilisation targets (Figure 2). Given such a pervasive and pivotal role of negative emissions in mitigation scenarios, their almost complete absence from climate policy discussions is disturbing and needs to be addressed urgently.

Pondering the difficulty of large-scale negative carbon emissions, but also their potential importance, I’m led to imagine scenarios like this:

In the 21st century we slowly wean ourselves of our addiction to burning carbon. By the end, we’re suffering a lot from global warming. It’s a real mess. But suppose our technological civilization survives, and we manage to develop a cheap source of clean energy. And once we switch to this, we don’t simply revert to our old bad habit of growing until we exhaust the available resources! We’ve learned our lesson—the hard way. We start trying to cleaning up the mess we made. Among other things, we start removing carbon dioxide from the atmosphere. We then spend a century—or two, or three—doing this. Thanks to various tipping points in the Earths’ climate system, we never get things back to the way they were. But we do, finally, make the Earth a beautiful place again.

If we’re aiming for some happy ending like this, it may pay to explore various ways to achieve negative carbon emissions even if we can’t scale them up fast enough to stop a big mess in the 21st century.

(Of course, I’m not suggesting this strategy as an alternative to cutting carbon emissions, or doing all sorts of other good things. We need a multi-pronged strategy, including some prongs that will only pay off in the long run, and only if we’re lucky.)

If we’re exploring various methods to achieve negative carbon emissions, a key aspect is figuring out economically viable pathways to scale up those methods. They’ll start small and they’ll inevitably be expensive at first. The ones that get big will get cheaper—per tonne of CO2 removed—as they grow.

This has various implications. For example, suppose someone builds a machine that sucks CO2 from the air and uses it to make carbonated soft drinks and to make plants grow better in greenhouses. As I mentioned, Climeworks is actually doing this!

In one sense, this is utterly pointless for fighting climate change, because these markets only use 6 megatonnes of CO2 annually—less than 0.02% of how much CO2 we’re dumping into the atmosphere!

But on the other hand, if this method of CO2 scrubbing can be scaled up and become cheaper and cheaper, it’s useful to start exploring the technology now. It could be the first step along some economically viable pathway.

I especially like the idea of CO2 scrubbing for coal-fired power plants. Of course to cut carbon emissions it would be better to ban coal-fired power plants. But this will take a while:

So, we can imagine an intermediate regime where regulations or a carbon tax make people sequester the CO2 from coal-fired power plants. And if this happens, there could be a big market for carbon dioxide scrubbers—for a while, at least.

I hope we can agree on at least one thing: the big picture is complicated. Next time I’ll zoom in and start talking about a specific technology for CO2 scrubbing.