Good Gas, Bad Gas By Marianne Lavelle National Geographic; December, 2012 Burn natural gas and it warms your house. But let it leak, from fracked wells or the melting Arctic, and it warms the whole planet.

The last rays of sun filter through the snow-covered spruces along the shore of Goldstream Lake, just outside Fairbanks, Alaska. Out on the lake Katey Walter Anthony stares at the black ice beneath her feet and at the white bubbles trapped inside it. Large and small, in layer upon layer, they spread out in every direction, like stars in the night sky. Walter Anthony, an ecologist at the University of Alaska Fairbanks, grabs a heavy ice pick and wraps the rope handle around her wrist. A graduate student holds a lighted match above a large bubble; Walter Anthony plunges the pick into it.

Gas rushing from the hole ignites with a whoomp that staggers her. “My job’s the worst, because usually you catch on fire,” she says, smiling. In the gathering twilight she and her team ignite one bubble after another.

The flames confirm that the bubbles are methane, the main component of natural gas. By counting and measuring them, Walter Anthony is trying to gauge how much methane is rising from Goldstream Lake—and from the millions of similar lakes that now occupy nearly a third of the Arctic region. The Arctic has warmed much faster than the rest of the planet in recent decades, and as the permafrost has melted, old lakes have grown and new ones have formed. Methane bubbles from their muddy depths in a way that is hard to quantify—until the first clear ice of fall captures a snapshot of the emissions from an entire lake.

Sometimes as Walter Anthony walks that ice, in Alaska, Greenland, or Siberia, a stamp of her boot is enough to release an audible sigh. Some lakes, she says, have “hot spots” where the methane bubbling is so strong that ice never forms, leaving open holes big enough to spot from an airplane. “It could be 10 or 30 liters of methane per day from one little hole, and it does that all year,” she says. “And then you realize there are hundreds of spots like that and millions of lakes.” By venting methane into the atmosphere, the lakes are amplifying the global warming that created them: Methane is a potent greenhouse gas. Carbon dioxide is the main one, because the atmosphere holds 200 times as much of it. But a given amount of methane traps at least 25 times as much heat—unless you burn it first. Then it enters the atmosphere as CO₂.

That’s the other side of this Jekyll-and-Hyde story: A lot of methane is being burned these days. In the past decade the technology called hydraulic fracturing, “fracking” for short, has enabled drillers in the United States to extract natural gas from deeply buried shales they couldn’t tap before. Natural gas supplies have surged; prices have plummeted. Fracking is now spreading around the world, and it’s controversial. The gas boom has degraded landscapes and polluted water. But it has also had environmental benefits. Natural gas burns much cleaner than coal. In part because American power plants have been switching from coal to cheap gas, U.S. emissions of CO₂ from fossil fuels fell last year, even as the world set another record.

The catch is, methane emissions are rising. What’s coming out of Arctic lakes is troubling, Walter Anthony says, because some of it seems to be coming not from bottom mud but from deeper geologic reservoirs that had hitherto been securely capped by permafrost—and that contain hundreds of times more methane than is in the atmosphere now. Still, most methane emissions today come from lower latitudes, and most are related more directly to human activities. A growing amount seems to be leaking, for instance, from gas wells and pipelines. Just how warm Earth gets this century will hinge in part on how

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we balance the good and bad of methane—on how much of it we capture and burn, and how much we inadvertently let loose.

Methane is the simplest hydrocarbon—a single carbon atom surrounded by four hydrogen atoms. It usually forms when larger organic molecules are broken down, either by microbes or by heat. The microbes produce it when they eat dead plant matter in wet, oxygen-poor environments. They’re the source of the methane bubbling up from Goldstream Lake; from swamps and marshes all over; from human-made rice fields, landfills, and manure lagoons; and from the stomachs of cows and other ruminants. Termites emit a lot of methane too.

Most of the natural gas we tap for fuel, however, was formed not by microbes but by heat and pressure deep underground—as oil and coal were, and often in the same places. In coal mines methane is an explosion hazard; in oil fields it was long considered a nuisance to be burned off or, worse, vented directly into the atmosphere. Liquid oil was more valuable as fuel and much easier to transport to markets. Then pipelines built during the post–World War II construction boom made gas more transportable. The energy industry began to exploit massive natural gas reservoirs in places like Russia, Qatar, and Iran.

The United States produces the bulk of its own gas, but U.S. production peaked in 1973. By 2005 the country seemed to be running short, and the industry was building expensive new tanker terminals to import liquefied natural gas. The fracking boom changed that. Since 2005 gas production from deep shales has increased more than tenfold; it now accounts for more than a third of total production, which last year surpassed the 1973 record. Within a decade, according to a Department of Energy (DOE) forecast, the U.S. will become a net exporter of gas.

Estimates of how much gas is locked up in shales and how long the boom can last have varied widely. In 2011 DOE put the amount of “unproved resources” of shale gas at 827 trillion cubic feet; in 2012 it cut that estimate by more than 40 percent. Production from fracked wells has declined faster than DOE analysts had expected. So some critics believe the boom is a bubble that will soon burst. But DOE still projects that U.S. gas production will rise rapidly and that shale gas will make up half the total by 2035.

And deep shales are not the last methane source. DOE and the industry are trying to figure out how to tap the largest one of all—the methane hydrates that lie frozen under vast areas of seafloor and Arctic permafrost. Worldwide, hydrates may contain more energy than all other fossil fuels combined. They’re usually snow-white and look like ice, but they’re strange stuff, and extracting the methane is tricky. Each molecule is trapped in a cage of water molecules that’s stable only at high pressure and low temperatures; change either just a bit, and the cage crumbles. The escaping methane balloons in volume by a factor of 164.

Oil companies working on continental margins have to take care that extracting oil through an overlying hydrate layer does not disrupt it and perhaps damage the well. Climate scientists worry that global warming could destabilize hydrate layers, on land or at sea, triggering a massive methane release that would amplify the warming. A few scientists take seriously a catastrophic scenario in which the release happens rapidly, within a human lifetime, and the planet’s temperature spikes.

The atmospheric methane concentration has risen nearly 160 percent since preindustrial times, to 1.8 parts per million. For a few years, from 1999 to about 2006, it seemed to level off. Some researchers credit Asian rice farmers, who began draining their paddies during the growing season to conserve water—which reduced methane emissions as well. Another theory credits the oil industry, which started capturing and selling methane it used to simply vent. Since 2006, though, atmospheric methane has been rising

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again. Many observers believe it’s no coincidence that the number of wells punched into deep shales has been soaring too.

Relief in Every Window, but Global Worry Too by Elizabeth Rosenthal and Andrew W. Lehren, New York Times; June 20, 2012

In the ramshackle apartment blocks and sooty concrete homes that line the dusty roads of urban India, there is a new status symbol on proud display. An air-conditioner has become a sign of middle-class status in developing nations, a must-have dowry item.

It is cheaper than a car, and arguably more life-changing in steamy regions, where cooling can make it easier for a child to study or a worker to sleep.

But as air-conditioners sprout from windows and storefronts across the world, scientists are becoming increasingly alarmed about the impact of the gases on which they run. All are potent agents of global warming.

Air-conditioning sales are growing 20 percent a year in China and India, as middle classes grow, units become more affordable and temperatures rise with climate change. The potential cooling demands of upwardly mobile Mumbai, India, alone have been estimated to be a quarter of those of the United States.

Air-conditioning gases are regulated primarily though a 1987 treaty called the Montreal Protocol, created to protect the ozone layer. It has reduced damage to that vital shield, which blocks cancer-causing ultraviolet rays, by mandating the use of progressively more benign gases. The oldest CFC coolants, which are highly damaging to the ozone layer, have been largely eliminated from use; and the newest ones, used widely in industrialized nations, have little or no effect on it.

But these gases have an impact the ozone treaty largely ignores. Pound for pound, they contribute to global warming thousands of times more than does carbon dioxide, the standard greenhouse gas.

The leading scientists in the field have just calculated that if all the equipment entering the world market uses the newest gases currently employed in air-conditioners, up to 27 percent of all global warming will be attributable to those gases by 2050.

So the therapy to cure one global environmental disaster is now seeding another. “There is precious little time to do something, to act,” said Stephen O. Andersen, the co-chairman of the treaty’s technical and economic advisory panel.

The numbers are all moving in the wrong direction.

Atmospheric concentrations of the gases that replaced CFCs, known as HCFCs, which are mildly damaging to the ozone, are still rising rapidly at a time when many scientists anticipated they should have been falling as the treaty is phasing them out. The levels of these gases, the mainstay of booming air-conditioning sectors in the developing world, have more than doubled in the past two decades to record highs, according to the National Oceanic and Atmospheric Administration.

And concentrations of the newer, ozone-friendly gases are also rising meteorically, because industrialized countries began switching to them a decade ago. New room air-conditioners in the United States now use an HFC coolant called 410a, labeled “environmentally friendly” because it spares the ozone. But its

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warming effect is 2,100 times that of carbon dioxide. And the treaty cannot control the rise of these coolants because it regulates only ozone-depleting gases.

The treaty timetable requires dozens of developing countries, including China and India, to also begin switching next year from HCFCs to gases with less impact on the ozone. But the United States and other wealthy nations are prodding them to choose ones that do not warm the planet. This week in Rio de Janeiro, Secretary of State Hillary Rodham Clinton is attending the United Nations Conference on Sustainable Development, also known as Rio+20, where proposals to gradually eliminate HFCs for their warming effect are on the provisional agenda.

But she faces resistance because the United States is essentially telling the other nations to do what it has not: to leapfrog this generation of coolants. The trouble is, there are currently no readily available commercial ozone-friendly alternatives for air-conditioners that do not also have a strong warming effect — though there are many on the horizon.

Nearly all chemical and air-conditioning companies — including DuPont, the American chemical giant, and Daikin, one of Japan’s leading appliance manufacturers — have developed air-conditioning appliances and gases that do not contribute to global warming. Companies have even erected factories to produce them.

But these products require regulatory approvals before they can be sold, and the development of new safety standards, because the gases in them are often flammable or toxic. And with profits booming from current cooling systems and no effective regulation of HFCs, there is little incentive for countries or companies to move the new designs to market.

“There are no good solutions right now — that’s why countries are grappling, tapping in the dark,” said Rajendra Shende, the recently retired head of the Paris-based United Nations ozone program, who now runs the Terre Policy Center in Pune, India.

An Unanticipated Problem

The 25-year-old Montreal Protocol is widely regarded as the most successful environmental treaty ever, essentially eliminating the use of CFC coolants, which are highly damaging to the ozone layer. Under its terms, wealthier countries shift away from each harmful gas first, and developing countries follow a decade or more later so that replacement technologies can be perfected and fall in price.

Concentrations of CFC-12, which had been growing rapidly since the 1960s, have tapered off since 2003, thanks to the treaty’s strict phaseout schedule. In 2006, NASA scientists concluded that the ozone layer was on the mend.

But that sense of victory has been eclipsed by the potentially disastrous growth in emissions from the newer air-conditioning gases. While a healthier ozone layer itself leads to some warming, far more warming results from the tendency of these coolant gases to reflect back heat radiating off the Earth.

When the treaty set its rules in the mid-1980s, global warming was poorly understood, the cooling industry was anchored in the West, and demand for cooling was minuscule in developing nations.

That has clearly changed. Jayshree Punjabi, a 40-year-old from Surat, was shopping for an air-conditioner at Vijay Sales in Mumbai on a recent afternoon. She bought her first one 10 years ago and

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now has three. “Now almost every home in Surat has more than one,” she said. “The children see them on television and demand them.”

Refrigeration is also essential for these countries’ shifting food supplies. “When I was a kid in Delhi, veggies came from vendors on the street; now they all come from the supermarket,” said Atul Bagai, an Indian citizen who is the United Nations ozone program’s coordinator for South Asia.

In 2011, 55 percent of new air-conditioning units were sold in the Asia Pacific region, and the industry’s production has moved there. Last year, China built more than 70 percent of the world’s household air-conditioners, for domestic use and export. The most common coolant gas is HCFC-22. In 2010, China produced about seven times the amount of that gas as the United States.

With inexpensive HCFC-22 from Asia flooding the market, efforts to curb or eliminate its use have been undercut, even in the United States. For example, although American law now forbids the sale of new air-conditioners containing HCFC, stores have started selling empty components that can be filled with the cheap gas after installation, enabling its continued use.

An Alert on Ocean AcidityBy John Collins Rudolf, New York Times; December 8, 2010

Carbon dioxide emissions from man-made sources are causing the acidity level of the world's oceans to rise at what is probably the fastest rate in 65 million years, threatening global fisheries that serve as an essential food source for billions of people, according to a new United Nations report.

Roughly 25 percent of the carbon dioxide generated by the combustion of fossil fuels enters the oceans, and as the gas dissolves in seawater it changes into carbonic acid. One result has been a rapid alteration in ocean chemistry that is already affecting marine organisms.

The acidity of the oceans has grown 30 percent since the beginning of the Industrial Revolution. At current emission rates, ocean acidity could be 150 percent higher by the end of the century, the report states.

Marine life and coral reefs have already shown vulnerability to rising levels of acidity, and the changes expected in coming decades are severe enough that they could have a serious impact on the ability of people around the world to harvest needed protein from the seas, according to Carol Turley, senior scientist at Britain's National Oceanography Center and the lead author of the report.

"We need to start thinking about the risk to food security," Dr. Turley said in a statement.

The report also warns that the rise in ocean acidity poses a severe threat to coral reefs, which are already under stress from pollution and the warming of oceans -- a concern shared by a growing number of marine scientists.

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Acidification could conceivably wipe out most of the world's already ailing coral reefs within a generation or two, said John Veron, former chief scientist of the Australian Institute of Marine Science, in an essay posted this week on the Web site Yale Environment 360.

"The potential consequences of such acidification are nothing less than catastrophic," Dr. Veron wrote.

As acidification continues, coral and marine organisms like shellfish will begin to suffer from osteoporosis -- an inability to fix calcium into shells and other structures.

"No doubt different species of coral, coralline algae, plankton and mollusks will show different tolerances, and their capacity to calcify will decline at different rates," Dr. Veron wrote. "But as acidification progresses, they will all suffer from some form of coralline osteoporosis."

"The result will be that corals will no longer be able to build reefs or maintain them against the forces of erosion," the article continues. "What were once thriving coral gardens that supported the greatest biodiversity of the marine realm will become red-black bacterial slime, and they will stay that way."

How to Buy Time in the Fight against Climate Change: Mobilize to Stop Soot and Methane

A short list of relatively simple actions taken to reduce greenhouse gases other than CO2 could help put the brakes on global warming--if implemented globally

By David Biello, Scientific American, Thursday, January 12, 2012 | 57

Humanity has done little to address climate change. Global emissions of carbon dioxide reached (another) all-time peak in 2010. The most recent international talks to craft a global treaty to address the problem pushed off major action until 2020. Fortunately, there's an alternative—curbing the other greenhouse gases.

Specifically, in the case of rapid action to slow catastrophic climate change, the best alternatives appear to be: methane and black carbon (otherwise known as soot). A new economic and scientific analysis published in Science on January 13 of the benefits of cutting these two greenhouse gases finds the benefits to be manifold—from human health to increased agricultural yields.

Even better, by analyzing some 400 potential soot- and methane-emission control measures, the international team of researchers found that just 14 deliver "nearly 90 percent" of the potential benefits. Bonus: the 14 steps also restrain global warming by roughly 0.5 degree Celsius by 2050, according to computer modeling.

That's because both methane and black carbon only remain in the atmosphere for a short time compared with CO2. As atmospheric physicist Veerabhadran Ramanathan of the Scripps Institution of Oceanography at the University of California, San Diego, said of such efforts to reduce atmospheric soot a few years ago: "If the world pays attention and puts resources to it, we will see an effect immediately. I'm talking weeks, at most a few months, not decades or centuries."

The 14 measures that would immediately slow global warming are:

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—Eliminate methane releases from coal mines—particularly in China—by capturing it and burning it.—Eliminate the venting or accidental release of methane co-produced by oil drilling (and, of course, gas drilling itself), particularly in Africa, the Middle East and Russia.—Capture gas from landfills in the U.S. and China as well as promote recycling and composting of biodegradable trash.—Occasionally aerate flooded rice paddies to prevent the growth of methane-producing microbes.—Stop leaks from natural gas pipelines, particularly in Russia.—Use bio-digesters—vessels in which microbes break down manure into gas—to cut methane from livestock globally.—Update wastewater treatment plants to capture methane.—Filter the soot produced by incomplete combustion of diesel fuel in vehicles, and attempt to eliminate inefficient internal combustion engine vehicles entirely.—Replace indoor cooking and heating fires with clean-burning cook stoves fired either by wood, manure or other biomass or, even better, methane.—Replace traditional brick kilns with more advanced firing methods.—Replace traditional ovens for turning coal to coke with modern technologies.—Ban the open burning of crop stubble and other agricultural waste.

The researchers estimate that cutting those 14 together could avoid between 700,000 and 4.7 million premature deaths (largely from smoky, unhealthy air) and increase crop yields by between 30 million and 135 million metric tons (due to concomitant reductions in ground-level ozone, otherwise known as smog, which forms from fugitive methane and blights crops in Brazil, China, India, the U.S. and elsewhere). In addition, the economic analysis suggests that many of these measures provide more value in benefits than they cost to implement.

Finally, the really good news is that every single one of the required technologies already exist and are being used in various parts of the world. For example, Senegal has "switched virtually its entire population from traditional stoves to modern ones, so it can be done," climate scientist Drew Shindell of NASA's Goddard Institute for Space Studies, lead author of the study, wrote in an e-mail. It is simply a matter of global adoption or, as the United Nations Environment Programme put it in a similar analysis last year, "much wider and more rapid implementation is required to achieve the full benefits."

In addition to saving lives, stopping soot may also preserve endangered ecosystems, such as the mountain glaciers of the Himalayas and Karakoram or Arctic sea ice. In fact, the computer modeling suggests cutting black carbon could forestall as much as two thirds of the warming in the Arctic—the fastest warming region of the globe—over the next 30 years. Even more significantly (from the human perspective), eliminating the atmospheric smut known as the "Asian brown cloud" could help maintain the monsoon patterns that bring water to India while reducing drought risk in places like the Sahel.

This doesn't mean that humanity would not have to deal with CO2 emissions—and would not be storing up future trouble by continuing to emit at our present pace—but it would buy time and, perhaps even more importantly, significantly reduce the chances of catastrophic climate change. Adding in cuts in yet more non-CO2 greenhouse gases—like the hydrofluorocarbons currently being phased out under the terms of the Montreal Protocol to eliminate the ozone hole—will also help. "These are things to do in addition to but not instead of reducing CO2 emissions," Shindell emphasized.

So why isn't this happening already? First and foremost, it is—in some parts of the world, at least. But short-term cost considerations, institutional structures and even societal priorities can stand in the way. For example, limited budgets might keep a municipality from installing methane capture at the local landfill in the U.S. Or an oil company might refrain from investing in similar methane capture at its wells because it can make more money investing in opening a new field instead. "In poor places, it really can be a lack of the upfront costs," Shindell added. There's also the not insignificant challenge of implementing such solutions globally—otherwise known as the problem of scale—as well as overcoming the reasons of

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engaging in traditional practices, such as burning the residue in agricultural fields to increase fertility, in the first place.

But there's a more fundamental reason for the inertia, according to the researchers, who note that "the benefits would not necessarily accrue to those incurring costs." That also explains our inaction on climate change generally. Or as Shindell noted "It's not trivial to get this done—even if it's beneficial for society as a whole."

Profits on Carbon Credits Drive Output of a Harmful Gas by Elizabeth Rosenthal and Andrew W. Lehren, New York Times; August 8, 2012

RANJIT NAGAR, India — When the United Nations wanted to help slow climate change, it established what seemed a sensible system.

Greenhouse gases were rated based on their power to warm the atmosphere. The more dangerous the gas, the more that manufacturers in developing nations would be compensated as they reduced their emissions.

But where the United Nations envisioned environmental reform, some manufacturers of gases used in air-conditioning and refrigeration saw a lucrative business opportunity.

They quickly figured out that they could earn one carbon credit by eliminating one ton of carbon dioxide, but could earn more than 11,000 credits by simply destroying a ton of an obscure waste gas normally released in the manufacturing of a widely used coolant gas. That is because that byproduct has a huge global warming effect. The credits could be sold on international markets, earning tens of millions of dollars a year.

That incentive has driven plants in the developing world not only to increase production of the coolant gas but also to keep it high — a huge problem because the coolant itself contributes to global warming and depletes the ozone layer. That coolant gas is being phased out under a global treaty, but the effort has been a struggle.

So since 2005 the 19 plants receiving the waste gas payments have profited handsomely from an unlikely business: churning out more harmful coolant gas so they can be paid to destroy its waste byproduct. The high output keeps the prices of the coolant gas irresistibly low, discouraging air-conditioning companies from switching to less-damaging alternative gases. That means, critics say, that United Nations subsidies intended to improve the environment are instead creating their own damage.

The United Nations and the European Union, through new rules and an outright ban, are trying to undo this unintended bonanza. But the lucrative incentive has become so entrenched that efforts to roll it back are proving tricky, even risky.

China and India, where most of the 19 factories are, have been resisting mightily. The manufacturers have grown accustomed to an income stream that in some years accounted for half their profits. The windfall has enhanced their power and influence. As a result, many environmental experts fear that if manufacturers are not paid to destroy the waste gas, they will simply resume releasing it into the atmosphere.

A battle is brewing. Disgusted with the payments, the European Union has announced that as of next year it will no longer accept the so-called waste gas credits from companies in its carbon trading system

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— by far the largest in the world — essentially declaring them counterfeit currency. That is expected to erode their value, but no one is sure by how much.

“Consumers in Europe want to know that if they’re paying for carbon credits, they will have good environmental effects — and these don’t,” Connie Hedegaard, the European commissioner for climate action, said in an interview.

Likewise, the United Nations is reducing the number of credits the coolant companies can collect in future contracts. But critics say the revised payment schedule is still excessive and will have little immediate effect, since the subsidy is governed by long-term contracts, many of which do not expire for years.

Even raising the possibility of trimming future payments “was politically hard,” said Martin Hession, the immediate past chairman of the United Nations Clean Development Mechanism’s executive board, which awards the credits. China and India both have representatives on the panel, and the new chairman, Maosheng Duan, is Chinese.

Carbon trading has become so essential to companies like Gujarat Fluorochemicals Limited, which owns a coolant plant in this remote corner of Gujarat State in northwest India, that carbon credits are listed as a business on the company Web site. Each plant has probably earned, on average, $20 million to $40 million a year from simply destroying waste gas, says David Hanrahan, the technical director of IDEAcarbon, a leading carbon market consulting firm. He says the income is “largely pure profit.”

And each plant expects to be paid. Some Chinese producers have said that if the payments were to end, they would vent gas skyward. Such releases are illegal in most developed countries, but still permissible in China and India.

As the United Nations became involved in efforts to curb climate change in the last 20 years, it relied on a scientific formula: Carbon dioxide, the most prevalent warming gas, released by smokestacks and vehicles, is given a value of 1. Other industrial gases are assigned values relative to that, based on their warming effect and how long they linger. Methane is valued at 21, nitrous oxide at 310. HFC-23, the waste gas produced making the world’s most common coolant — which is known as HCFC-22 — is near the top of the list, at 11,700.

The United Nations used the values to calibrate exchange rates when it began issuing carbon credits in 2005 under the Clean Development Mechanism. That system grants companies that reduce emissions in the developing world carbon credits, which they are then free to sell on global trading markets. Buyers of the credits include power plants that need to offset emissions that exceed European limits, countries buying offsets to comply with the Kyoto Protocol — an international environmental treaty — and some environmentally conscious companies that voluntarily offset their carbon footprint.

Since the United Nations program began, 46 percent of all credits have been awarded to the 19 coolant factories, in Argentina, China, India, Mexico and South Korea. Two Russian plants receive carbon credits for destroying HFC-23 under a related United Nations program.

“I was a climate negotiator, and no one had this in mind,” said David Doniger of the Natural Resources Defense Council. “It turns out you get nearly 100 times more from credits than it costs to do it. It turned the economics of the business on its head.”

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Destroying the waste gas is cheap and simple, but it is hard to know exactly how much any one company has earned from doing so, since the market price for carbon credits has varied considerably with demand — from about $9 to nearly $40 per credit — and they can be sold at a discount through futures contracts.

The production of coolants was so driven by the lure of carbon credits for waste gas that in the first few years more than half of the plants operated only until they had produced the maximum amount of gas eligible for the carbon credit subsidy, then shut down until the next year, United Nations reports said. The plants also used inefficient manufacturing processes to generate as much waste gas as possible, said Samuel LaBudde of the Environmental Investigation Agency, an organization based in Washington that has long spearheaded a campaign against what he called “an incredibly perverse subsidy.”

Michael Wara, a law professor at Stanford University, has calculated that in years when carbon credits were trading at high prices and coolant was dirt-cheap because of the oversupply, companies were earning nearly twice as much from the credits as from producing the coolant itself.

The United Nations, recognizing the temptation for companies to jump into the lucrative business, has refused since 2007 to award carbon credits to any new factories destroying the waste gas. And last November, it announced that in contract renewals, factories could claim credits for waste gas equivalent only to 1 percent of their coolant production, down from 3 percent. The United Nations believes that eliminates the incentive to overproduce, said Mr. Hession, the former Clean Development Mechanism board chairman.

Even with these adjustments, credits for destroying waste gas this year remain the most common type in the United Nations system, which rewards companies for reducing all types of warming emissions. Eighteen percent of credits in 2012 will go to the 19 coolant plants, compared with 12 percent to 2,372 wind power plants and 0.2 percent for 312 solar projects for the carbon dioxide emissions avoided by the clean energy they produce.

In India, coolant plants received about half of the United Nations carbon credits awarded to companies in that country, for destroying their waste gas, during the system’s first five years. They accrued the power and money to fight efforts to roll back the subsidy.

Compared with Indian representatives, Chinese diplomats have shown greater willingness at international meetings to consider altering the subsidy for waste gas credits, said Stephen O. Andersen, a former United States Environmental Protection Agency official who is now with the Institute for Governance and Sustainable Development in Washington. That is because China has a more centrally controlled economy and because it is developing an industry based on newer coolants. “It’s easier for them to put the national interest before the interest of one manufacturing sector,” he said.

A bigger question is just how much the European Union’s decision to disallow, as of next year, the waste gas credits in its immense carbon trading system will decrease their value.

Banks and companies holding such credits have been rushing to cash them in or sell them. And the potential devaluation of the carbon credits has an impact in other industrialized nations, since the carbon credit projects involve foreign sponsors and investors, who sometimes received carbon credits in exchange for services or financing.

A coolant factory in Monterrey, Mexico, that receives carbon credits is 49 percent owned by Honeywell. Goldman Sachs bought many of its carbon credits.

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Such credits are likely to have some continued value, because they can be used in other environmental programs that allow their use, like voluntary ones through which companies offset the emissions generated by having a conference or travelers opt to pay a fee to offset the emissions from an airplane flight.

Mr. LaBudde, of the Environmental Investigation Agency, who has long campaigned against the subsidy, said he hoped that no one would buy these “toxic” credits that “have no place in carbon markets” and that they would quickly disappear. In its latest annual report, Gujarat Fluorochemicals acknowledged that its carbon credits “may not have a significant market” starting next year because European companies have previously been their primary buyers.

Mr. Hanrahan, of IDEAcarbon, said that the credits could, at the very least, be sold at a low price to traders who see the possibility for marginal profit in a way similar to the market for junk bonds. Even if all the proposals to make the carbon trade far less valuable succeeded, the 19 factories certified to generate carbon credits by destroying the waste gas could earn $1 billion from that business over the next eight years, according to projections by IDEAcarbon.

And even as the economics shift, one big environmental question remains: Without some form of inducement, will companies like Gujarat Fluorochemicals continue to destroy the waste gas HFC-23? Already, a small number of coolant factories in China that did not qualify for the United Nations carbon credits freely vent this dangerous chemical. And atmospheric levels are rapidly rising.

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