News and Outreach: John Reilly

By: Michael Vaughan

Two interesting issues that in the banality of the U.S. presidential campaign will likely never be discussed:

1. the extent of the sea ice covering the Arctic Ocean is now the smallest observed in the three decades since consistent satellite observations of the polar cap began, according to scientists from NASA;

2. an important study finds a carbon tax would enable the United States to find the means to both close the deficit gap and revive the economy.

While the two contenders are slanging each other about tax returns and birth certificates both surely know that NASA and MIT have to be taken seriously. Mitt Romney (not MIT) made his fortune in Boston and Barack Obama went to Harvard. MIT (Massachusetts Institute of Technology) has more new technology patents than most countries on Earth. Harvard has been lucky enough to have had among its alums a well-known billionaire who created Facebook plus eight who have became President of the United States.

When evidence becomes undeniable you have to wonder why those who make big decisions won’t discuss the evidence. Intelligent public policy matters. Yet the news is always obsessed about whether the teachers get their new raise or not. Meanwhile there are policy options that make a huge amount of sense that are never discussed, or even mentioned, in the daily news cycle.

The MIT study found that taxing carbon at $20 a ton in the U.S. would generate $1.5-trillion in revenue in a 10-year period, which would reduce corporate and personal income taxes, maintain social services spending and reduce the deficit.

“With the carbon tax there are virtually no serious trade-offs. Our analysis shows the overall economy improves, taxes are lower and pollution emissions are reduced,” said John M. Reilly, co-director of MIT’s Joint Program on the Science and Policy of Global Change. The study said the carbon tax would lower pollution by 20 per cent by 2050 and prevent oil imports from rising. It would also, most importantly, shift energy markets to clean technology.

Some Republications are coming around to the fact that the United States is facing the expiration of the “Bush” tax cuts in 2013 – the fiscal cliff. Even supply-side economists are reluctantly embracing a fee on carbon emissions. There are many global warming deniers in the GOP but others believe if the U.S. needs to raise revenue, why not just tax global warming pollution? The MIT analysis suggests that a carbon tax would be a more economically beneficial way of raising revenue than payroll or income taxes.

Additionally, the MIT report argues that a carbon tax would accomplish other important objectives. Fossil-fuel use would go down, oil imports would shrink slightly and U.S. carbon-dioxide emissions would decline. A carbon tax is tax levied on all carbon content of fuels. Carbon dioxide is a heat-trapping "greenhouse" gas. Carbon is present in hydrocarbon fuels – coal, petroleum, and natural gas – and is released as carbon dioxide (CO2) when they are burned. In contrast, non-combustion energy sources – wind, sunlight, hydropower and nuclear – do not convert hydrocarbons to CO2.

Yet, even with a carbon tax, the United States would still fall short of its long-term climate goals, which involve an 80 per cent cut in emissions below 1990 levels by mid-century. According to MIT calculations, a modest carbon tax, on its own, wouldn’t get the United States close to that longer-term mark; however, it would still make sense as a more economically efficient way of raising revenue.

If an intelligent public policy can improve the economy, reduce trade deficits, help the environment and keep the U.S. from going broke – why wouldn’t it at least be discussed in the election of the so-called most powerful person on Earth?

By: Brad Plumer

With the United States facing the expiration of a slew of tax cuts in 2013—the dread “fiscal cliff”—there has been plenty of interest in offbeat tax-reform proposals. And one idea that a few economists keep knocking around is a fee on carbon emissions. After all, if we need to raise revenue, why not just tax global-warming pollution?

A new paper from the MIT Global Change Institute lays out how a carbon tax might work in practice. The authors model what would happen if, this December, Congress enacted a small fee on carbon emissions to fend off a portion of the tax hikes and spending cuts that are scheduled to occur. The carbon tax would be levied directly on fossil fuels—on coal that comes out of the mine, say, or oil that’s shipped in from overseas—and would start at $20 per ton of carbon in 2013, rising 4 percent each year thereafter.

The authors, Sebastian Rausch and John M. Reilly, estimate that this tax would raise $1.5 trillion over the next 10 years. If that revenue were then used either to cut income taxes, reduce payroll taxes, or deflect cuts to social-spending programs, the MIT authors find, most Americans would be slightly better off than if Congress simply let the fiscal cliff hit, with the Bush tax cuts and payroll tax cuts expiring automatically. (Using the carbon tax in this way would lead to an 0.02 percent bump in consumption and leisure over time.)

Now, the betting line is that Congress will do something to avert the looming tax hikes and spending cuts, so this isn’t a terribly realistic scenario. Implementing a carbon tax next year would still hurt the economy—it would just hurt slightly less than the fiscal cliff. Still, the broader point of the MIT analysis is to suggest that a carbon tax could be a more economically beneficial way of raising revenue than, say, payroll or income taxes. So even if Congress waited until 2014 or 2015 or whenever the U.S. economy has recovered, replacing other taxes with a carbon tax could still provide a minor economic boost (see the first graph below).

A carbon fee usually gets criticized for hurting poorer Americans the most—they spend the biggest slice of their income on gasoline and other energy-intensive products, after all. But Rausch and Reilly found that a lot of the distributional effects depend on what Congress does with the revenue, as shown in the chart below:

CTCorp = carbon tax used to cut corporate tax rate, CTPersInc = carbon tax used to cut income tax rate, CTPayroll = carbon tax used to cut payroll taxes, CTTransfer = carbon tax used to bolster social welfare programs like Medicaid

The green line shows how different income groups would be affected in 2015 if the carbon tax was used to fend off cuts to social welfare programs like Medicaid. Lower-income Americans would benefit significantly, while wealthier Americans would take a small hit. By contrast, the red and blue lines show the effects if revenue from the carbon tax was used to cut the corporate tax or personal income tax—in those cases, higher-income Americans would come out ahead. If, however, a carbon tax was used to cut payroll taxes—that’s the black line—then the welfare effects in 2015 are more or less neutral.

The MIT report argues that a carbon tax would accomplish a few other things as well. Fossil-fuel use would go down, oil imports would shrink slightly, and U.S. carbon-dioxide emissions would decline. On that last point, however, it’s worth noting that the carbon tax proposed by the MIT study only gets the United States a fraction of the way toward its long-term climate targets, as shown in this graph:

Blue line: MIT reference case with no carbon tax. Black line: EIA reference. Green line: Scenario with MIT carbon tax in place.

With the carbon tax proposed by MIT (that’s the green line in the chart above), U.S. emissions would be 14 percent below 2006 levels by 2020 and 20 percent below 2006 levels by 2050. That’s lower than if there was no carbon tax at all.

Yet the United States would still fall short of its long-term climate goals, which involve an 80 percent cut in emissions below 1990 levels by mid-century. According to MIT calculations, a modest carbon tax, on its own, wouldn’t get the United States close to that longer-term mark. It might make sense as a more economically efficient way of raising revenue. But the tax would either have to be hiked dramatically or combined with other clean-energy measures in order to make a significant dent in tackling global warming.

Read the news release on this report.

Read the study's coverage in the Washington Post Here, Here and Here; the Wall Street Journal, CNN Opinion, The Hill, Bloomberg BNA, the Globe and Mail, Reuters, and Nature Here and Here.


By: John M. Reilly and Sebastian Rausch

This time last year, Washington’s AAA credit rating was downgraded, as Congress held hostage an agreement on a debt ceiling increase while looking for a long-term debt reduction plan. A year later, not much has changed.

Congress is no closer to reaching consensus on reining in our nation’s debt. The Bi-Partisan Tax Commission laid out the harsh reality: Closing the deficit would require both tax increases and cuts to key programs like Social Security.

Though some of these difficult changes may be inevitable, what if we could avoid some tax hikes and spending cuts? And did it while stimulating the economy and cutting pollution and oil imports? A carbon tax would do just that, according to our new study.

The Congressional Budget Office found that a tax on carbon dioxide, starting at $20 per ton, could raise $1.25 trillion over the next decade. Our research puts those numbers higher — at $1.5 trillion. With that money, Congress could extend the Bush income tax cuts that are due to expire on Dec. 31, and also avoid serious cuts to social programs. Replacing this with revenue from a carbon tax would also modestly improve the economy.

Lowering taxes and maintaining funding for social programs would give Americans more money to spend – boosting the economy. This is particularly true in the short term – if tax cuts and spending are skewed toward lower income households, which spend more of their income, stimulating weak consumer demand.

On the other hand, cutting these programs – as well as raising other taxes – would drag down our economy. So much so that the loss would more than offset the cost of a carbon tax.

This win-win alone should be enough for our leaders to put a price on carbon, forcing fossil fuel users to pay a tax based on the amount of emissions they produce.

But there’s another win we’d get at no extra cost: a win for our future health, security and prosperity.

This carbon tax plan, our research shows, would cut emissions by more than 20 percent by 2050, while keeping oil imports from rising. With this economically beneficial approach, the U.S. could lead the way to a global solution for carbon emissions rather than stand in the way.

A carbon tax would also help shift the market to clean technologies like solar, wind and other low-carbon energy sources. This shift would happen in a way that makes economic sense: By making dirtier sources more expensive and raising revenue rather than spending it through narrow tax incentives.

By encouraging low-carbon energy, a carbon tax could cut our use of foreign oil by 10 million barrels a day by 2050. It would also give U.S. consumers and businesses the flexibility to choose technologies that save energy and money – boosting sales of more fuel-efficient cars and other goods. With greater efficiency, fuel and energy costs could actually go down – not up – as the U.S. economy turns from spending and borrowing to saving and investing in our future.

A carbon tax isn’t a new idea in Washington. In fact, it has support from both sides of the aisle. Conservative economists — like Mitt Romney’s adviser Greg Mankiw and Ronald Reagan’s former adviser Arthur Laffer — agree: When it comes to the pure economics, a carbon tax makes the most sense. Yet partisan gridlock and the political fear of anything labeled “tax” has blocked sensible solutions.

There are usually hefty tradeoffs and hard-set winners and losers in politics. This time, however, that doesn’t have to be the case.

With these benefits to our economy, our environment and our security, a carbon tax is the winning solution that our nation needs to carve out a prosperous future.

John M. Reilly is co-director for the Joint Program on the Science and Policy of Global Change at the Massachusetts Institute of Technology and a senior lecturer at MIT’s Sloan School of Management. Sebastian Rausch is an assistant professor of energy economics at ETH Zurich and contributes to research at the Joint Program on the Science and Policy of Global Change at MIT.

The inescapable importance of China to global energy and climate efforts has compelled the Joint Program—in collaboration with Tsinghua University—to launch a special research effort called the China Energy and Climate Project.

 A growing population and rapid development will put a strain on land used to grow food over this century. But if reforestation is used to avoid climate change it will create further strain, says a new MIT study.

It’s no surprise that the United States and China are the world’s top greenhouse-gas emitters. What may be surprising is the country that ranks third in the lineup: Indonesia. Indonesia is a major culprit not because of its traffic or power plants, but because of its massive deforestation.

Deforestation accounts for almost 20 percent of global emissions—more than the world’s entire transportation sector. But saving the trees—as beneficial as it would be to the changing climate — comes at a significant cost as a growing, wealthier population competes for food, says a new MIT study.

“With a larger and wealthier population, both energy and food demand will grow,” says John Reilly, the lead author of the study and the co-director of the MIT Joint Program on the Science and Policy of Global Change. “Absent controls on greenhouse gases, we will see more emissions from fossil-fuel use and from land-use change. The resulting environmental change can reduce crop yields, and require even more land for crops. So this could become a vicious circle.”

The Reilly et al. study, recently published in Environmental Science & Technology, compares the effects of slashing emissions from energy sources alone to a strategy that also incorporates emissions associated with land use.

The report finds that, with a growing global population, fast-developing nations, and increasing agricultural productivity and energy use, the world is on the path to seeing average temperatures rise by as much as 6 degrees Celsius by the end of the century. Even with an aggressive global tax on energy emissions, the planet will not be able to limit this warming to 2 degrees Celsius—the target world leaders have agreed is needed to avoid dangerous climate change. But when the tax is applied to land-use emissions, the world community could come much closer, with temperatures by the year 2100 rising 2.4 degrees Celsius above pre-industrial levels.

To go one step further in reducing emissions the study incorporates biofuels production, which could increase carbon storage on land and be a cleaner source of energy, lessening the use of fossil fuels. The researchers find that increased biofuels production could cut fossil-fuel use in half by the end of the century—from 80 percent of energy without a tax to 40 percent with a tax—and further limit warming to bring the world just shy of the target.

The world could get even closer to the target, the study shows, by creating economic incentives for storing carbon on land—such as through reforestation. In combination with the global carbon tax, this could “bring the world closer to keeping warming below the 2 degree Celsius temperature,” Reilly says.

But there are always drawbacks.

“The environmental change avoided by reducing greenhouse-gas emissions is substantial and actually means less land used for crops,” Reilly says. “The big tradeoff is that diverting this amount of land to carbon storage, and using land to produce biofuels, leads to substantial rises in food and forestry prices.”

Food prices could rise more than 80 percent, the study shows. Along with this, nations could become wealthier, with global GDP increasing fivefold. On average, the share of a household’s budget for food, even with higher prices, might fall from 15 percent to 7 percent. But for poorer regions of the world, the food budget share could increase, meaning these food price impacts could have disproportionate effects on poorer regions.

Food shortages and higher food prices are becoming a major challenge, according to Jonathan Foley, director of the University of Minnesota’s Institute on the Environment, who spoke at a recent MIT event.

“In the last 20 years we’ve produced 28 percent more crops. But in the next 38 years, we need to double that growth,” Foley said. “We’re not going to grow our way out of the problem … we must look at other possibilities.”

An advocate of ending deforestation, Foley said we need to grow food more efficiently.

Reilly agrees, and says his study puts an emphasis on more effective use of land to produce food. Part of this means more efficient (intensive) use of pasture and grazing land. But, he says, the carbon tax scenarios he tests make the problem that much more difficult—with biofuels and carbon sequestration using up more land.

“And with all three of these demands for land—food, biofuels and carbon storage—the competition is intense, and as a result, food prices rise. So this is an important tradeoff the world needs to consider.”

As global leaders prepare to gather for the Rio+20 sustainable development summit in Brazil next week, the International Monetary Fund (IMF) and a collection of economists from MIT and other organizations has released a report to help leaders confront the price tag associated with climate change. The publication— Fiscal Policy to Mitigate Climate Change: A Guide for Policymakers—details the most effective methods to reduce emissions and contain costs, namely through carbon pricing.

Until now, leaders have focused on slowing warming to 2 degrees Celsius to prevent catastrophic changes associated with climate change. Because this would mean taking drastic measures to hold emissions at about today's levels, researchers at MIT argue that leaders should be realistic and start smaller because the time to act is quickly running out. Their research—Emissions Pricing to Stabilize Global Climate—is a chapter within the IMF guide.

“Negotiations on the exact emission reduction target have been going on for a long time without much substantial progress,” says Sergey Paltsev, lead author of the MIT study and associate director for economic research at the Joint Program on the Science and Policy of Global Change. “But it is better to start with some policy that reduces emissions because even a small initial step is important as it sets the process on track.”

IMF’s Managing Director Christine Lagarde points to a tax or trade system.

“Perhaps we can help with a simple concept that everybody can understand—getting the prices right,” Lagarde said in a speech at the Center for Global Development. “Getting the prices right means using fiscal policy to make sure that the harm we do is reflected in the prices we pay. I am thinking about environmental taxes or emissions trading systems under which governments issue—and preferably sell—pollution rights.”

The MIT research suggests an emissions price—organized through either a tax or cap-and-trade system—of about $20 to $40 per ton by 2020 to help the world community reach less stringent targets that would keep warming to 2.9 or 3.6 degrees Celsius.

“These less stringent targets are more realistic and reachable, and they still reduce the risk of more severe climate impacts,” Paltsev says. But, he warns, “we have never experienced such changes and do not know exactly how the Earth will respond, so the smaller the changes we make, the greater the risk of something unexpected and bad happening.”

Still, making small changes is better than not acting at all, Paltsev says, and we shouldn’t wait for technology to fix the problem for us.

“We can wait for a miracle technology, like biofuels with carbon capture and storage, to appear and become economical— allowing us to reach more stringent target—but then we place our bets on something which may or may not materialize,” Paltsev says.

The longer the global community waits to take action, the higher the price tag could be and the less likely the world will be able to meet even less stringent targets. This could mean “unprecedented levels of damage and degradation” if current trends in production and consumption continue, United Nations Undersecretary General Achim Steiner said in a recent statement. He added, “The moment has come to put away the paralysis of indecision, acknowledge the facts and face up to the common humanity that unites all peoples.”

Andrew Steer, special envoy for climate change for the World Bank, agrees.

“We will turn the tide against climate change only when core economic policymakers wake up to the urgency of the issue and factor it into their fiscal and economic policies,” he said.

Making progress one step at a time

Even if all countries were able to agree on a uniform path forward, slowing emissions would require a complex burden-sharing system including incentives and compensation for emerging and developing countries—continuing an ongoing struggle about who pays what to confront the challenge.

While such an international effort may take time, the Green Climate Fund—formed in Cancun, Mexico, in 2010—could help developing countries. Meanwhile, major emitters like the United States, European Union and China could establish a relatively small carbon tax, the revenue from which could be returned to citizens to balance out the higher energy prices and increase public support. The idea is similar to parts of a proposal by U.S. Sen. Maria Cantwell (D-Wash.).

Still, cap-and-trade—a system invented by American economists—is far from being implemented in the United States, as countries around the world take steps to implement the system—like China.

“Just as many of our best innovations are produced in China, they may beat us in implementing such a system,” John Reilly, a co-director of the MIT Joint Program on the Science and Policy of Global Change and an author of the IMF chapter, said recently. "We're really being left behind.”

China is not the only country that has an edge on the United States. The EU, Australia, New Zealand and South Korea have already begun to set hard emission limits, and cap-and-trade programs are gaining traction in Brazil and Mexico as well.

Joëlle Chassard, manager of the Carbon Finance Unit of the World Bank, said in a statement that it was heartening to “see increasing interest in, and support for, new market-based mechanisms to mitigate climate change.”

Paltsev agrees that these systems are encouraging and useful, even at the local level. But, he says, “It is also important to harmonize the efforts” and “all major emitters, including the U.S., need to participate.”

By: Katherine Bagley

While the national climate debate is fixed on whether Earth is warming, climate scientists are focused on understanding how bad it will be.

The global warming debate in Congress, the states and on the campaign trail centers on two issues: Is Earth warming, and if so are humans to blame?

But ask most climate scientists, and they'll tell you that these are the only questions not in dispute. Climate change is a matter of how bad and by when, they'll say—not whether.

"Scientists are inherently skeptical," says Lonnie Thompson, a paleoclimatologist at Ohio State University, who has led studies of glaciers and ice sheets in 16 countries. "After enough evidence and observation, though, you have to start to accept findings. That is what happened with climate change. This wasn't a rash conclusion."

"There is not any serious debate about whether anthropogenic climate change is happening," says Daniel Sarewitz, co-director of the Consortium for Science, Policy and Outcomes at Arizona State University and a professor of science and society. "Scientists are certain about that, and it is unfortunate that the national debate is lagging so far behind."

The public and political discourse on global warming was framed by the 2007 report of the UN Intergovernmental Panel on Climate Change (IPCC), which concluded that climate change is occurring and human activity is the cause. That seminal report, and the subsequent coverage and debate, split the country into two partisan camps, with Democrats generally accepting the scientific consensus and Republicans questioning or flat-out denying it.

Missing from the discussion is the perhaps surprising, and rising, view of many scientists—that the UN climate panel gravely underestimated the immediacy and danger of global warming.

The IPCC process itself is partly, though not entirely, to blame. "It takes seven years to produce an IPCC report," says Thompson, who is also an IPCC author. "By the time it is published, the science is already dated ... and the models being used aren't accurately assessing how rapidly these changes are taking place."

There are real-world implications at stake, Thompson says. "We are in for tougher scenarios than what are being relayed in the reports."

A Flawed IPCC Assumption

The IPCC, the world's leading scientific body on global warming, is charged by the UN with assessing research and releasing periodic reviews of climate risks, which governments often use to set targets for cutting carbon emissions. In 2007, the panel shared the Nobel Peace Prize with Vice President Al Gore.

At the core of its assessments are IPCC "scenarios"—summaries of coming climatic conditions like global temperature and sea-level rise, which are based on a number of assumptions about future greenhouse gas emissions. One of those assumptions is that the world will make good on its carbon-cutting pledges.

Therein lies a key flaw, says John Reilly, co-director of the Massachusetts Institute of Technology's (MIT) Joint Program on the Science and Policy of Global Change and an expert on climate economic models. Many nations have failed to take promised steps to slash global warming emissions, particularly China and the United States, the world's biggest polluters. Even in the European Union greenhouse gases are on the rise. Yet the IPCC doesn't account for this.

The result, says Reilly, is that emissions today are higher than what the IPCC predicted in 2007. The panel's middle-of-the-road scenarios, for example, estimate that the world would emit between 27 and 28 billion metric tons of carbon dioxide in 2010. In reality, 30.6 billion metric tons of CO2 were released that year, the latest figures available, says data from the International Energy Agency. While that may seem like a small difference to a lay person, climate experts say that small increases can steamroll into something much bigger.

What Newer Climate Models Show

In 2009, Reilly and his colleagues at MIT, along with researchers from Penn State, the Marine Biological Institute in Massachusetts and the U.S. Environmental Protection Agency, decided to model forecasts for climate that assumed the world would continue with business as usual.

Their results, published in the June 2012 issue of Climatic Change and online last year, found that without major greenhouse gas cuts the median global temperature would increase by 5 degrees Celsius (9 degrees Fahrenheit) by 2100, compared to the IPCC's worst-case prediction of a 3.5 degree Celsius rise (6.3 degrees Fahrenheit). 

The study found that the Arctic would warm up to three times as much as was foreseen by the IPCC. There would also be more severe extreme weather events and greater ocean warming, sea-level rise and ocean acidification.

"The IPCC suite of scenarios provide ... a bit too rosy of a picture," says Reilly. "Our study shows that without action, there is virtually no chance that we won't enter very dangerous territory."

Even moderate action isn't likely to help. Follow-up work by these same researchers published this year in MIT's annual Energy and Climate Outlook found that if countries achieve the emission cuts they promised at international climate negotiations, the global temperature would still increase by over 4 degrees Celsius (7.2 degrees Fahrenheit), with a significant chance of a 5 degree Celsius rise by century's end

For some scientists, however, the IPCC's findings are extreme.

"I'm surprised there are those who think the IPCC is too conservative," says John Christy, atmospheric scientist at the University of Alabama in Huntsville, IPCC author in 2001 and a well-known skeptic of human-caused climate change. "I think the simple evidence is very clear—the IPCC models overestimate the warming of the climate system." The IPCC declined to comment on the record.

Missing Ice Sheets and Slow Timing

Perhaps the biggest controversy surrounding the IPCC scenarios is that they omit the rapid melting of the Greenland and Antarctic ice sheets in sea-level rise projections.

Several researchers, including Thompson, the polar ice expert from Ohio State University, and James Hansen, head of the NASA Goddard Institute for Space Studies, have been vocal critics of that omission, which they say dramatically skews the IPCC scenarios. If the Greenland and Antarctic ice sheets, the only two in the world, continue to melt at their current pace, Thompson and other scientists believe sea levels could rise several feet and swamp coastlines this century, not the 8 to 17 inches projected in the IPCC mid-range scenarios.

"Those [ice sheets] are the big elephants in the room," says Thompson. "They are going to play a big role, yet they aren't taken into account." (The IPCC left them out because of uncertainty about how to predict effects of ice-sheet meltdowns in climate models.)

Some scientists say the very nature of the IPCC process means its reports can never be truly up to date. Research must be published at least two years before the release of an IPCC assessment to be considered. That lag time also means the projections will be on the conservative side, Thompson says. He argues that as scientific understanding of climate change improves, and as CO2 emissions continue to rise, the predictions grow more dire.

Reilly, the MIT scientist, says most scientists studying climate change today are viewing "the seemingly unstoppable rise in global greenhouse emissions" with "increasing alarm."

Why Aren't Scientists More Vocal?

So, if climate scientists are convinced that the Earth is warming faster than expected, then why aren't more speaking out?

The researchers interviewed for this story said many have retreated into silence to avoid the small but vocal band of climate skeptics. "Researchers find it hard to raise significant questions even within the climate science community for fear that it will be exploited by the skeptics," says Sarewitz, the science and society professor from Arizona State University.

"Climate science is a huge, sprawling area of discussion," explains Sarewitz, and skeptics are known to seize on arguments as proof that the science linking human activity to global warming is dubious.

Indeed, there are still many points not understood in climate science. Long-term changes in solar activity and their effects on the climate system are not well known. The effect of aerosols on global temperature is still uncertain, because they all react differently to atmospheric heat. Sulfates, for example, block sunlight, which in turn can cool the climate, while black carbon absorbs sunlight and can accelerate warming. Few doubt that sea levels will rise, but how fast and by how much is hotly contested.

There are also major limitations with climate models. They can predict whole-Earth scenarios better than localized scenarios, meaning regional trends still can't be predicted with much accuracy. They also don't reflect the physics of cloud formation well, an issue the IPCC has made a research priority.

While none of these undermine the consensus that climate change is human-caused, Sarewitz says, any dissension helps skeptics chisel away at the perception of scientific agreement. "It all makes it hard for the disinterested citizen ... to actually know how to untangle the conversation and who to trust."

Is silence the answer? Not according to Thompson of Ohio State, who admits to being "frustrated' by skeptic tactics and scientists' lack of response to them. "If they want to be more than just a historian documenting the change—if they want to make a difference—[scientists] have to speak out about these issues."  Thompson himself regularly speaks about climate change, even allowing TV and print journalists to join his polar ice expeditions.

Reilly agrees. "Without interaction [with the public], it becomes too easy for people to vilify or defy those who disagree or agree with them, and there is little chance for real understanding."

In an effort to share what is known, what isn't, and what can and cannot be done about climate change, MIT's John Reilly and Kerry Emanuel joined UMass Amherst researchers as part of a "Global Warning" panel convened by The Boston Globe.

Today’s global challenges will significantly affect how we grow our food. But these challenges are so complex and intertwined that response measures require collaboration and a broad, integrated lens.

 By: Vicki Ekstrom, Joint Program on the Science and Policy of Global Change

EPA's top air official, Gina McCarthy, leads roundtable discussion.

Looking to tap the knowledge of some of the nation's leading energy and environment experts, and update them on new and proposed standards, the U.S. Environmental Protection Agency's top air official visited MIT's campus last Friday, Jan. 27. Gina McCarthy, EPA's assistant administrator for the Office of Air and Radiation who led a roundtable discussion which was hosted by MIT's Joint Program on the Science and Policy of Global Change and moderated by the program's co-director, John Reilly.

A return home for the Massachusetts native who spent more than 25 years working on environmental issues in the state, McCarthy said she saw the meeting as an opportunity to "learn from the experts who have been so valuable in providing the research and the science" her office needs to be successful.

Robust science, and clear cost-benefits associated with that science, is critical, McCarthy said — a lesson roundtable participant and environmental economics Professor Michael Greenstone helped her realize when he was the chief economist for President Obama's Council of Economic Advisers during the first year of the administration.

"I think the agency has tremendously benefitted from that, specifically the air program because we are under constant scrutiny," McCarthy said. "Everything these people know intersects very directly with the work I've been doing for the president."

The visit came just days after President Obama's State of the Union address, where he laid out his intention to take an "all-of-the-above" approach toward America's energy future.

"In this administration we are looking for everything from commitments to renewables, that would be wind and solar, but also recognizing that coal will have a place in the mix," McCarthy said of the president's vision. "We're asking ourselves from the EPA side what that means for our upcoming rules on greenhouse gases and source performance standards for powerplants. How do you write it in a way that's consistent with the rules and still allows a place for new coal and new technologies?"

Leadership on mercury
 

Joint Program on Global Change
Co-Director John Reilly

Noelle Selin, who participated in the discussion, was also excited to hear the president mention mercury.

"I do think that the Mercury and Air Toxics Standards are something we've been waiting for, for a long time, and they are a really forward-looking rule," Selin said.

She noted that Massachusetts has lead the way in controlling mercury, perhaps due to McCarthy's earlier leadership, and that the state will especially gain from the national rule because it is upwind of polluting coal-mining states to its south.

• See "MIT researcher: U.S. taking leadership on mercury in the environment" to learn more about Selin's view of the mercury standards.

Mentioning the global negotiations on mercury — scheduled to wrap up in January 2013, after the next presidential election — Selin asked what role the new standards might play in the global arena as China's mercury emissions continue to grow and endanger the gains made by the new rule.

"We were hoping that if we put out the powerplant rule [mercury standards] that would bolster our role in the discussion," McCarthy said. "It was one of the issues we considered when we were going through the process of forming the rule. We had to do our part … we had to have a legitimate position in the international discussion." 

Tapping the value of natural gas

McCarthy acknowledged that the mercury standards come while the cost of natural gas is low, which she said is "changing the energy world" and making some coal-fired powerplants "ineffective, inefficient and not competitive."

MIT Energy Initiative Director Ernest Moniz agreed: "I think we all agree that the mercury rules are absolutely critical in terms of displacing some coal, in addition to the economics of coal and gas with natural gas prices below $3 per million Btu."

But Christopher Knittel, an energy economics professor at the MIT Sloan School of Management, pointed out that natural gas deposits can be viewed as a huge opportunity — but also, a huge risk.

One of the challenges with natural gas is that the extraction process — a process called hydraulic fracturing — emits Volatile Organic Compounds (VOCs), such as methane, which cause smog and are associated with some health effects such as cancer. Methane is also a greenhouse gas that contributes to climate change.

Richard Schmalensee, director of the Center for Energy and Environmental Policy Research, addressed another challenge: the role that states play.

"The state's roles are problematic because you've got all this gas in places that have never had experience with anything like it," Schmalensee said.

McCarthy said there is a need for standard best practices within the industry — a topic the president addressed in his speech, as he challenged natural gas companies not to follow in the footsteps of the oil industry in terms of polluting now and worrying about it later.

"The good news about that is when you capture the VOCs you capture the methane. When you capture methane you sell it," McCarthy said. "So the cost-effectiveness of those strategies is quite good."

The EPA is close to finalizing a rule in April 2012 that would reduce VOCs from the oil and natural gas industry.

Meeting the Climate Challenge

The inclusion of climate change was another exciting point for McCarthy in the president's address.

But Susan Solomon, a professor of atmospheric chemistry who recently joined MIT from the National Oceanic and Atmospheric Administration (NOAA), said she thought the president missed an opportunity to expand on that point.

"This issue of climate change isn't one that's going to be solved by everyone pitching in. It's not like recycling where if we can all do our part we'll be better off," Solomon said. "It really does require new technologies and investments. So the most important thing that a citizen can do is to engage in a discussion about that and I think he missed an opportunity to call for engagement, including by Republicans."

McCarthy said one of the challenges of the present situation is that nobody wants to invest in anything that doesn't offer an immediate payback. The innovative new technologies needed to actually make a difference in the climate challenge are years, perhaps decades, away and require significant investments.

"And I think it's the government's job to look way beyond the immediate payback by establishing priorities for research and innovation," McCarthy said.

EPA's new greenhouse gas reporting data is one sign of progress that McCarthy believes has helped advance the climate change conversation.

"I actually think that has spurred tremendous amounts of opportunity for climate change to get back into a reasonable, rational discussion," McCarthy said. "I'm excited that the president is talking about that — as well as clean energy. Not replacing one for the other. Because it is a challenge we need to meet head on."