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	Photo: Paul Kishimoto

by Audrey Resutek | MIT Joint Program on the Science and Policy of Global Change

Graduate students from the Joint Program on the Science and Policy of Global Change taught a series of classes in January as part of MIT’s annual Independent Activities Period (IAP) that were designed to bring students and community members up to speed on basic climate science, climate policy, and the state of international climate negotiations.

International climate action

Amanda Giang, a graduate student in the Engineering Systems Division, led a session on January 30 on recent climate negotiations. Climate change is a vexing international problem in part because it is a commons problem—a type of problem which many graduate students may already be familiar with, she said.

A dirty kitchen is an example of a commons problem, said Giang, who has roommates. “We all share the kitchen, so it’s in no one’s best interest to clean the kitchen alone. If I clean the kitchen myself, I have to do all the work while everyone gets the benefit. But if no one cleans the kitchen we all suffer. What we really need is some sort of coordinated collective action, where I take out the trash and my roommate does the dishes.”

Because of this, an international agreement is the best route for action. Giang reviewed the recent history of global climate negotiations, including the UN’s efforts leading up to the next round of talks in Paris this winter, where countries are expected to come to an agreement on post-2020 climate action. Giang also discussed existing greenhouse gas mitigation efforts in the US and China, and the recent emissions deal between the two countries.

Economic measurements

Paul Kishimoto, a graduate student in the Engineering Systems Division, led sessions on January 29 and January 30 on the economics of climate change and climate policy.

Economists measure the effects of climate change as costs, both direct and indirect. As an example, Kishimoto asked the class to consider how statistically warmer weather might affect a runner who goes jogging on the Charles. If the runner goes jogging when it’s too hot and gets heat stroke and has to go to the hospital, it is a cost directly related to climate change. If the runner avoids running and misses out on an activity that they would otherwise do, it’s counted as an indirect, or counterfactual, cost of climate change. Calculating both the costs of climate change and the costs of policies allows researchers to evaluate the effectiveness of policies addressing climate change, he said.

Photo: Amanda Giang.

Kishimoto also discussed how different types of policies aimed at reducing greenhouse gas emissions work, including measures like carbon taxes and trading plans, regulations, and policies encouraging research and development of new technology.

Climate science measurements

Daniel Gilford and Jareth Holt, graduate students in the Department of Earth, Atmospheric and Planetary Sciences, led a session on January 29 on how climate scientists measure climate change.

Gilford started the class out by explaining the concept of radiative forcing, which is a measure of the net difference between the energy the Earth and atmosphere absorbs from sunlight, and the energy released back into space after a change in the atmospheric composition (such as increasing CO₂). A change that traps more heat in the Earth system is a positive radiative forcing and contributes to warming. The primary gas causing increased radiative forcing is CO₂, but other gases like methane, nitrous oxide, and ozone also play a role.

Jareth Holt discussed how climate models account for factors that affect radiative forcing. To do this, models have become more complex, Holt said. For example, in the 1990s, climate models underestimated the importance of aerosols in calculating radiative forcing, and had simple representations. Models now have more detailed representations of how aerosols behave in the atmosphere.

On the other hand, there are reasons why researchers might want to simplify models. Modern climate models use supercomputers, he explained, and can take weeks or even months to make one simulation. Simpler models run more quickly, and allow researchers to complete a larger number of simulations, helping to understand the uncertainty in the climate system. As a result, climate modeling requires constant balancing between complexity and computational efficiency.

Climate fundamentals

Daniel Gilford and Jareth Holt led a session on January 26 covering basic climate science, and the history of the discipline. Climate science, Holt said, is the study of variability, patterns, and statistics over time.

	Photo: Daniel Gilford.

The field can trace its roots back to the 1820s, when Joseph Fourier discovered that the Earth’s atmosphere traps heat. The modern study of climate change got its start in the 1890s when Svante Arrhenius built the first simple model balancing energy in the Earth system. He determined that adding CO₂ to the atmosphere traps energy, causing warming, which is a principle still used by climate scientists today.

Gilford and Holt also explained what makes a gas a greenhouse gas. The Earth’s atmosphere is made of mostly nitrogen and oxygen, but those gases absorb almost none of the energy given off by the Earth’s surface. Instead, small amounts of other gases, like water vapor and CO₂, trap the most energy. Other gases like methane and nitrous oxide are present in even smaller amounts, but because they strongly absorb energy at different wavelengths than CO₂ and water vapor, they can also contribute dramatically to warming.

For the full list of 2015 Global Change IAP Clasess click here. 

By Carolyn Y. Johnson | Boston Globe

When a historic blizzard dumps a record-breaking amount of snow on the region, it’s only a matter of time before someone ventures a wry joke about climate change. Maybe there’s an upside to a warmer world, after all? Less shoveling.

But the halfhearted punchline doesn’t hold up to scientific scrutiny, according to recent research from a Massachusetts Institute of Technology atmospheric scientist. In fact, a warming world could mean less overall snow in a given year, but no reprieve from extreme snow events, at least in places like Boston.

To science, not all snowstorms are the same: average snowfall is likely to decrease in most places, but the most aggravating, traffic-snarling, work-stopping, back-straining extreme storms like the one that just buried Boston could actually get bigger.

“Most studies have been about how much snow falls in a season or in a year and call that average snowfall. But of course, in terms of disruption to society or economic disruption, we’re also interested in heavy snowfalls,” said Paul O’Gorman, an associate professor of atmospheric science at MIT who published his findings in Nature. “In some regions, fairly cold regions, you could have a decrease in the average snowfall in a year, but actually an intensification of the snowfall extremes.”

O’Gorman published his findings last August, back when snow was far from the front of mind. He is currently in Australia, where the weather is sunshine and showers instead of snow, but took the time to answer a few questions by email about his counterintuitive finding.

Q: Can you explain how a warming climate might affect snowfall?

A: There are two competing effects as the climate warms: the increasing temperature causes a changeover from snow to rain, but it also increases the amount of water vapor in the atmosphere. For a particular place and time of year, which effect wins out depends on the temperature to begin with.

Read more...

By David L. Chandler
Photo credit: Bryce Vickmark
MIT News Office

After a career that included work as a White House advisor in the Carter administration and as a partner at Goldman Sachs, Larry Linden SM ’70, PhD ’76 has turned his attention to what he says is the most critical issue facing humanity today: the threat of catastrophic global climate change.

Linden, speaking on campus Wednesday in the opening event of the MIT Climate Change Conversation, urged his audience to join him in making the issue a top priority — and in pushing elected leaders to take concrete action now, before changes to the world’s atmosphere and oceans become irreversibly damaging. And the most effective approach, he emphasized, is by putting a price on carbon emissions from fossil fuels.

That could take a number of forms: an outright tax on carbon, a cap-and-trade arrangement, or a revenue-neutral combination of fees and rebates. While the present political climate in the United States may make any such agreement an uphill battle, Linden stressed that his foundation — the Linden Trust for Conservation — and other groups are working hard to find centrist, bipartisan approaches that could lead toward the goal of limiting global climate change.

Pointing to unexpectedly rapid changes in public opinion in other areas, Linden said that while the prospects for political action on climate may now appear bleak, “We can be surprised, and I hope we will. This is an idea that could go from impossible to inevitable overnight.”

Linden, a board member of the World Wildlife Fund and former chairman of the board of directors of Resources for the Future, described the evolution of his thinking on climate change. He said his awareness of environmental issues started early: As a child in Pasadena, Calif., he personally experienced the terrible, pre-Clean Air Act smog of the Los Angeles basin. Now, he said, “I’m doing everything in my power to move our country to act [on climate change] at the scale that’s required.”

Unpredictable changes

At the current pace, Linden said, we face a rise in temperature of as much as 4 to 6 degrees Celsius by 2100 — and the carbon dioxide humans are now adding to the air will stay there for centuries or even millennia. This could lead, he said, “to abrupt, unpredictable and potentially irreversible changes” — such as the release of frozen methane, or the death of the Amazon rainforest — that could greatly amplify the impacts. If such large changes do occur, Linden said, “I don’t think it’s an overstatement to call this a planetary catastrophe.”

While Linden said the fossil fuel industry will fiercely resist any proposed regulations or fees aimed at limiting carbon emissions, he added that past experience gives reason to treat industry’s claims with some skepticism: Proposals to limit automobile pollution to deal with California’s smog problems faced similar objections, which proved unfounded.

“The financial system is an extremely complex, interrelated system — just like the climate system,” Linden said. While companies never like to be told what to do, he said, if federal rules constrain their actions, they will abide by the law.

In 2009, when federal cap-and-trade legislation was proposed in Congress and passed in the House, Linden was encouraged, thinking that this would be a be “a great start.” But when the proposed law was dropped without even being brought to a vote in the Senate, “I practically fell off my chair,” he said. In the years since, the idea has not resurfaced in Congress.

Slashing emissions

But something along those lines is exactly what is needed now, Linden said. Research has shown that to avert the most drastic climate consequences, greenhouse gas emissions must be cut by about 80 percent over the next four or five decades. In addition, massive new investment in research and development on alternative energy sources is needed, he said.

The most essential change in policy, Linden said, is a mechanism for “internalizing the externalities”: capturing the great societal costs of fossil fuel emissions in the costs of the fuels themselves. “It could be a cap-and-trade system, or a tax or a fee on carbon, or a limit on emissions,” he said.

Linden said that his foundation is supporting a revenue-neutral carbon tax as the next major national policy step. Studies have shown, he said, that an initial tax of $15 per ton of carbon emitted, with significant annual increases, could cut emissions in half by 2050.

The key, he said, lies in public action to force politicians to act. But the very nature of the issue — requiring strong action now to avoid consequences many years hence — makes action difficult: “If you designed a problem to maximize the political difficulty of addressing it, you couldn’t do much better,” Linden said. “We will therefore need extraordinary political leadership.”

“Bipartisan support is needed,” he added, noting that the Linden Trust is actively working to build support across the political spectrum. “We’re looking for centrist solutions,” he said. Like the climate itself, “our political system is an extremely complicated, interrelated system. There are possible positive feedback loops, and many nonlinear thresholds that can produce irreversible impacts. … That’s what we need to look for now.”

While the process might take years, Linden said, “We have to fight the political fight.” In the meantime, he said, state initiatives might provide useful “working examples” for national action.

Maria Zuber, MIT’s vice president for research, introduced this kickoff event of MIT's Climate Change Conversation, an effort to involve the MIT community in seeking ways in which the Institute might contribute to addressing the threat of global climate change. The proposals arising from this process, Zuber said, would be “rooted in science, would be bold, would encourage personal engagement.”

Zuber added that while this has been “a divisive issue on many campuses, of the many things that we could possibly do, there must be some things that we can all agree on that would be useful to do, and maybe we should start with doing those.”

Linden's talk was sponsored by the Committee on the MIT Climate Change Conversation, which will organize a series of events during the spring semester to engage the community in thinking about how the Institute can contribute to confronting climate change.

David L. Chandler | MIT News Office

Dara Entekhabi, an MIT professor of civil and environmental engineering and of earth, atmospheric and planetary sciences, is the science team leader of NASA’s Soil Moisture Active Passive (SMAP) satellite, scheduled to be launched from Vandenberg Air Force Base in California on Jan. 29. The satellite will provide measurements of the moisture in the top 2 inches of the soil, everywhere on Earth, over the course of its planned three-year mission, as well as specifying whether that water is liquid or frozen. Entekhabi discussed what he hopes this mission will be able to accomplish.

Q. How much of an improvement will SMAP represent over current ways of assessing soil moisture around the world? Why is it important to be able to do so?

A. Why we need soil moisture information, and what capability SMAP adds, can be explained by following a timeline of what we know about how the Earth system works, starting in the 1980s and 1990s.

Until then, the study of the water cycle — the storage and flow of water in the environment — was partitioned between meteorology and hydrology. So long as water was in the form of vapor and precipitating clouds, it was in the domain of meteorologists. Only after the precipitation hit the surface was its infiltration into soil, runoff, and stream flow in the domain of hydrologists.

Around the 1980s there was a transformative change in our thinking, with the emerging capability of fast computers and Earth system modeling. Much of that thinking, in fact, was formed at MIT: We started thinking about two-way interaction and coupling between the land and the atmospheric branches of the water cycle. In order to couple the systems, we soon realized that the key variable to track is surface soil moisture. But the ground networks to observe this variable were too few and far between to yield any meaningful insights. To make global and dynamic maps of this, we had to take on the vantage point of Earth-orbiting satellites. Starting in 2000, I became involved with NASA, and we formed a team to propose a satellite mission whose design is specifically optimized to make high-resolution and high-accuracy maps of surface soil moisture. The paired microwave-radar and radiometer instruments can sense through clouds and vegetation. The rotation of the antenna while orbiting the Earth produces a wide swath of surface measurements that can track changes in soil moisture.

Q. What would you expect to be some of the most significant findings that this mission will be able to make, and what kind of impact could these findings have?

A. With these high-quality measurements, we will have unprecedented insight into how the cycling of water weaves through its land and atmospheric branches. Because the evaporation and condensation of water also entails exchanges of energy, and because the uptake of atmospheric carbon dioxide by plants requires thawed conditions and exchange of water, soil moisture also links the three fundamental cycles of the Earth system — the water, energy, and carbon cycles — over land. These three cycles work together like gears in a clock: Perturbations in one gear will affect the others. If soil moisture were fixed everywhere, these three cycles would vary independently of one another. But with dynamic and responsive soil moisture, the three are linked over land, with synchronized variations. That is a big difference for the Earth system and its cycles. So with observations of soil moisture and improvement in links between the water, energy, and carbon cycles, our understanding of how the Earth system works will be on a new and higher level. With improved characterization and modeling, the predictions of the global and the regional environment — from short-term weather forecasts to global climate-change projections — will be impacted.

Q. How difficult is it to measure these conditions from orbit, and what kinds of tests will need to assess the accuracy of the data returned by the mission?

A. The main technological challenge has been the design of the large antenna and its rotation to make a scan of a wide swath over each orbit. Given the long microwave wavelengths (about 21 centimeters), to focus on a high-resolution spot on the surface the antenna has to be large in diameter. SMAP has a 6-meter lightweight mesh reflector that stows like an umbrella and unfurls in space. Then this large structure has to be rotating at about 15 rounds per minute to map the surface. This is pushing the technology to its limits. We have developed a calibration and validation plan where we pull data in real time from ground sensor networks, perform quality control, and compare with the SMAP data. Over the last two summers we have had two rehearsals of the end-to-end system. The calibration and validation will also include two airborne field campaigns during the summers of 2015 and 2016. Preliminary science data will be released after six months, and after one year we need to demonstrate, using ground-truth observations, that the data meet the accuracy requirements agreed upon by the project and NASA sponsors.

China Energy and Climate Project Director Professor Valerie J. Karplus appeared on Channel NewsAsia to discuss the impacts and broader significance of the Korean emissions trading system kicking off last week. Watch the interview below.


 

Anna Petherick writes for Nature Climate Change about emissions pledges from the United States and China for, including emissions projections from China Energy and Climate Project.

Read the full column here.

Amanda Peterka | E&E reporter

Bioenergy production would boom and spur steep reductions in greenhouse gas emissions if a global price is slapped on carbon, Massachusetts Institute of Technology researchers say in a report released today.

Examining bioenergy production under a $15-per-metric-ton carbon price that would rise steadily to $59 in 2050, researchers found production hitting 150 exajoules by 2050 -- compared with below 50 exajoules without a carbon price.

Global greenhouse gas emissions would plunge 16 percent under that scenario, the report says, cautioning that the carbon price studied doesn't take into account land-use changes. Taking into account emissions from land-use changes, including deforestation, it says greenhouse gas reduction would be nearly 60 percent from the no-carbon-price baseline.

"The study is one of the most in-depth evaluations to date of how bioenergy might fit into a low-carbon future," MIT said in a release. "The research team developed a cutting-edge modeling tool covering a comprehensive range of bioenergy pathways."

The MIT Joint Program on the Science and Policy of Global Change says its study goal was to see how bioenergy would compete with other low-greenhouse-gas options on a level playing field.

The researchers used the Economic Projection and Policy Analysis model to create both the carbon price scenarios and assumptions about economic, productivity and population growth without a carbon price. The model examined seven first-generation biofuel crops and two cellulosic biofuel conversion technologies -- bioelectricity and heat.

The model also accounted for international trade, ethanol blending limits, changes in land and production costs, and existing policies such as the federal renewable fuel standard, among other factors.

"Biofuels are only one channel for bioenergy," said Niven Winchester, an environmental energy economist at MIT. "If you want to study how land can be used to meet our energy needs, you have to think of all the different ways to use what grows on that land -- including food, feed and fuel."

The carbon price scenario resulted in efficiency improvements and energy use reductions, the report says. Electricity consumption in 2050 dropped 19 percent, while there was 73 percent less electricity from coal.

With a carbon price in the MIT model, bioenergy use rose from 8.5 exajoules in 2015 to 152.4 exajoules in 2050 -- or about a quarter of global energy needs.

The model found that corn ethanol would be produced in the United States until 2025, when it would become uneconomical.

After 2025, cellulosic ethanol would become the primary form of bioenergy; by 2020, cellulosic ethanol would account for about 57 percent of the globe's total bioenergy consumption.

Increased energy prices under a carbon price would make grasses -- one of the main inputs for cellulosic ethanol -- more attractive, while cellulosic producers would face lower land costs than other biofuel producers, according to the report. Rising electricity prices would also increase the revenue that cellulosic producers could receive from producing electricity as a co-product.

Africa and Brazil would become the largest bioenergy producers in a world where cellulosic ethanol is the main form of bioenergy, the MIT study found.

"Africa can become a key player in supplying global energy, if agricultural expertise can be transferred to this region," Winchester said. "It has the right climate and a large amount of land, but also the potential for deforestation if policy safeguards aren't in place."

The growth in cellulosic ethanol assumes that production costs fall over the next 35 years and that ethanol-blending constraints disappear by 2030 partly through the use of more flex-fuel cars.

MIT found that pricing greenhouse gas emissions from bioenergy land-use changes significantly increases the amount of greenhouse emission reductions that occur as a result of bioenergy expansion.

Pricing land use changes would prompt a global reforestation of 800 million hectares between 2010 and 2050, according to the study. In 2050, cumulative carbon-dioxide-equivalent emissions would be 37,381 million metric tons if land-use changes were priced, compared to 74,140 million metric tons if they were not.

"The report concludes that changes spurred by the carbon price, including bioenergy production, could cut greenhouse gas emissions by more than half, with a catch -- to achieve the cut, the carbon price must cover emissions from changing land use," MIT said. "Without this safeguard, deforestation becomes a major concern as forests are cleared to make way for farmland."