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By Jennifer Chu

For the past two summers, Australians have sweated through record heat waves, with thermometers climbing as high as 118 degrees Fahrenheit in parts of the country. In January, officials were forced to halt tennis matches during the Australian Open due to extreme heat — a decision made following several days of sizzling temperatures.

Now MIT researchers have found that the intensity of summer temperatures in Australia and elsewhere in the Southern Hemisphere may be better predicted as early as the previous spring by an unlikely indicator: ozone.

From their study, published in the Journal of Climate, the scientists found that as the springtime ozone hole’s severity varies from year to year, the temperatures in Australia and southern regions of Africa and South America reveal correlations: Years with higher springtime ozone experience hotter summers, and vice versa.

The results suggest that ozone levels may help meteorologists predict the severity of summertime temperatures months in advance.

“No one has actually looked at the variation of ozone as a way to forecast or predict the climate or the next summer’s temperature,” says lead author Justin Bandoro, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “This could be especially important for farmers, and for areas like southeastern Australia, where most of that nation’s population resides.”

Bandoro’s MIT co-authors include Susan Solomon, the Ellen Swallow Richards Professor of Atmospheric Chemistry and Climate Science, and postdoc Aaron Donohoe, as well as David Thompson of Colorado State University and Benjamin Santer of Lawrence Livermore National Laboratory.

A spring forecast for summer temperatures

In 1987, countries around the world signed the Montreal Protocol, an international treaty that established a global phase-out of chemicals that cause ozone depletion. Because of the long lifetime of the chemicals, the ozone hole will continue to occur for many years, but it is expected to slowly begin to become less severe in the next several decades.

Bandoro and his colleagues analyzed annual ozone measurements, from 1979 through the most recent heat wave in 2013.

The team combined data from various sources, including a station in Antarctica that has measured total ozone levels in the same atmospheric column since the 1950s. The team performed a correlation analysis to identify links between ozone levels and variables such as temperature, precipitation, and wind patterns.

Although the ozone hole won’t close for many years, its intensity does vary somewhat from one year to another, and the depth of the hole affects an atmospheric phenomenon known as the Southern Annular Mode, which describes the wind patterns that circle Antarctica and influence the strength and position of fronts and storm systems in the Southern Hemisphere.

In years with high springtime ozone, the researchers found that winds shifted, bringing hotter summer temperatures to much of Australia and parts of southern Africa and South America. Lower ozone levels reversed this behavior, with winds leading to cooler summertime temperatures to these same regions.

Expect more extreme temperatures as ozone hole recovers

The link between springtime ozone and summertime temperatures is particularly strong for the present period, while ozone is still in a recovery phase. When the researchers examined this link from a period before the ozone hole had begun to form, they observed a much weaker correlation.

The implication, Bandoro says, is that as ozone levels likely rise in the coming decades, these parts of the Southern Hemisphere will probably experience systematically hotter summers.

“We can expect that these types of summers are going to be more frequent as the ozone hole recovers in coming decades,” Bandoro says. “When the ozone hole is deep, it essentially holds back climate change from showing its face, and Australia is just starting to feel this effect in the summertime in years with shallower ozone holes.”

David Karoly, a professor of earth sciences at the University of Melbourne, says the MIT group has shown, for the first time, a strong relationship between the severity of summer temperatures in Australia and the strength of the ozone hole the previous spring. The results, he says, point to a long-term warming trend in the Southern Hemisphere.

“As the ozone hole recovers this century, the masking effects of ozone depletion causing reduced summer warming over the Southern Hemisphere will disappear,” says Karoly, who did not participate in the study. “Then there will be an acceleration of the summer warming trends over Australia and South Africa, as the ozone hole recovers and the masking influence disappears.”

by Peter Dizikes

Powerful, destructive tropical cyclones are now reaching their peak intensity farther from the equator and closer to the poles, according to a new study co-authored by an MIT scientist.

The results of the study, published today in the journal Nature, show that over the last 30 years, tropical cyclones — also known as hurricanes or typhoons — are moving poleward at a rate of about 33 miles per decade in the Northern Hemisphere and 38 miles per decade in the Southern Hemisphere.

“The absolute value of the latitudes at which these storms reach their maximum intensity seems to be increasing over time, in most places,” says Kerry Emanuel, an MIT professor and co-author of the new paper. “The trend is statistically significant at a pretty high level.”

And while the scientists who conducted the study are still investigating the atmospheric mechanisms behind this change, the trend seems consistent with a warming climate.

“It may mean the thermodynamically favorable conditions for these storms are migrating poleward,” adds Emanuel, the Cecil and Ida Green Professor of Earth and Planetary Sciences at MIT.

The implications are serious, since the movement of peak intensity means regions further north and south of the equator, which have not previously had to face many landfalls by violent cyclones, may now have greater exposure to these extreme weather events. That, in turn, could lead to “potentially profound consequences to life and property,” the paper states. “Any related changes to positions where storms make landfall will have obvious effects on coastal residents and infrastructure.”

Moving with the trade winds?

The paper, “The Poleward Migration of the Location of Tropical Cyclone Maximum Intensity,” was co-written by James P. Kossin — who is the lead author — of the National Oceanic and Atmospheric Administration's National Climatic Data Center; Gabriel A. Vecchi of the National Oceanic and Atmospheric Administration; and Emanuel.

To conduct the study, the scientists used international data from 1982 to 2012, collected by NOAA’s National Climatic Data Center. They used the location of peak intensity of cyclones as a benchmark because it is a more consistent metric than statistics such as storm duration: The duration can be harder to estimate because of difficulties in establishing precisely when a storm should first be considered a tropical cyclone.

While there are regional differences in the poleward movement of cyclones, the fact that every ocean basin other than the northern Indian Ocean has experienced this change leads the researchers to suggest, in the paper, that this “migration away from the tropics is a global phenomenon.”

However, Emanuel notes, the global mechanisms underlying the trend are a matter for further research.

“We think, but have not yet been able to establish, that this is connected to independently observed poleward expansion of the Hadley circulation,” Emanuel says, referring to a large-scale pattern of global winds, which in recent years has also moved further poleward. The paper notes the potential impact of vertical wind shear, which inhibits cyclone formation; data suggests a decrease in wind shear in the tropics and an increase at higher latitudes.

Emanuel notes that researchers in the field are continuing to examine the links between storm migration and global warming. Over the past three decades, the incidence of cyclones in the tropics has actually diminished — because while tropical cyclones may become more intense in a warmer climate, it is actually more difficult to generate them.

Ocean temperatures between 82 and 86 degrees Fahrenheit seem to be “ideal for the genesis of tropical cyclones,” Emanuel says, “and as that belt migrates poleward, which surely it must as the whole ocean warms, the tropical cyclone genesis regions might just move with it. But we have more work to do to nail it down.”

Michael Mann, a professor of meteorology and director of the Earth System Science Center at Penn State University, says the matter of cyclone migration is “a very interesting new angle on the larger issue of how climate change may be impacting tropical cyclone activity.”

Overall, Mann adds, “The findings seem quite plausible. We know that human-caused climate change is leading to a poleward shift in certain features of the atmospheric circulation. … It would be surprising if these shifts were not influencing tropical cyclones. This study shows that they are, by causing a poleward migration in the zones where atmospheric shear is either favorable or prohibitive to tropical cyclone formation.” In practical terms, he says, the result may have “considerable implications” for coastal cities in the long term.

David Chandler
MIT News Office

MIT has announced a major new campuswide initiative to promote transformative, cross-disciplinary research relating to the environment.

The initiative will be formally launched in the fall, and its founding director will be Susan Solomon, the Ellen Swallow Richards Professor of Atmospheric Chemistry and Climate Science. Maria Zuber, MIT’s vice president for research and the E.A. Griswold Professor of Geophysics, stewarded the establishment of the new initiative, and expressed gratitude to Solomon for having agreed to serve as its first leader.

“Professor Solomon is one of the finest climate scientists in the world,” Zuber says. “Her service in the coming year will be of immense value to MIT, and to the world.” A search will be mounted for a permanent director to run the initiative after its first year.

A major component of the initiative will be the Abdul Latif Jameel World Water and Food Security Lab (J-WAFS), whose creation was announced this week; J-WAFS was established through a major gift from MIT alumnus Mohammed Abdul Latif Jameel. Headed by John Lienhard, the Jameel Professor of Water and Food, the lab is intended to help humankind adapt to a rapidly rising population, a changing climate, and increasing urbanization and development. The lab will work toward environmentally benign, scalable solutions for water and food supply across a range of regional, social, and economic contexts. 

Regarding the environment initiative, Solomon says, “Our faculty, students, and staff have a deeply shared vision of being responsible stewards of the environment. This initiative will focus and amplify the aspirations of our community to understand, inform, and seek solutions to pressing problems of the natural world and built environment.”

This new initiative, she says, will promote research that engages wide participation by members of the MIT community to address the most significant interdisciplinary problems in our environment, spanning the physical and social sciences; engineering; and urban planning and policy.

“The goal of the initiative will be very specific: for faculty members to self-organize into teams of people who are interested in defining genuinely new research directions; to come up with ideas across schools; and to propose research that might not easily be funded by current federal agencies, which tend to be defined by disciplinary areas,” Solomon says. Such interdisciplinary research is recognized as a key way to bring about significant advances in technology and understanding.

Like the MIT Energy Initiative (MITEI), the new program is also expected to produce detailed, comprehensive studies in particular areas of concern — in this case, large-scale environmental issues. “Such studies by MIT would be welcomed on Capitol Hill,” Solomon says.“One of the most important challenges of our time is the question of how to build a sustainable human society,” MIT President L. Rafael Reif wrote in an email to the MIT community this morning. “The intense interest in this subject from our students and faculty reflects a shared sense of urgency and obligation. With Professor Solomon’s leadership, the environment initiative will help focus MIT’s distinctive strengths on advancing science, engineering, management, design and policy solutions to help drive the kind of progress required in time to make a difference.”

The initiative, which does not yet have a formal name, will start with funding for five years of operation, partly provided by MIT; after that it is expected to be self-sustaining, Solomon says. It will tie together research undertaken by many departments and centers at MIT, including, in addition to J-WAFS, the Department of Earth, Atmospheric and Planetary Sciences; the Department of Urban Studies and Planning; the Department of Civil and Environmental Engineering; the Center for Global Change Science; and the Earth System Initiative, among others. Some themes of the new initiative will link closely with ongoing efforts in MITEI, particularly on climate change and water.

The search for the director was announced in February by Provost Martin Schmidt. The search committee, chaired by Professor Markus Buehler, included Professors Rob van der Hilst, Eran Ben-Joseph, JoAnne Yates, and Melissa Nobles. Professors Robert Armstrong and Vladimir Bulović also served on the committee; they were asked to help think through coordination with existing MIT initiatives. The committee worked with students to get their input.

The initiative will put out a call for initial interdisciplinary proposals this fall, Zuber says, adding: “We want new ideas. MIT can bring its special talents to bear to address global concerns, in the process drawing in people from across the campus.”

Additionally, a group consisting of Solomon, Zuber, Schmidt, and Armstrong (who serves as director of MITEI) will lead a series of conversations around campus on how MIT should engage to address the issue of climate change. This activity will include a series of lectures by prominent speakers representing a diverse set of perspectives.

The initiative will place a high priority on engaging the many students whose interests center on the environment and sustainability issues, Solomon says.

“There are a lot of opportunities for synergies,” she continues. “The initiative will take advantage of the traditionally open atmosphere at MIT, which fosters interactions among people working in very different fields of study. That spirit of collaboration, and the possibilities it unleashes, are very powerful.”

Global warming is rapidly turning America the beautiful into America the stormy, sneezy and dangerous, according to a new federal scientific report. And those shining seas? Rising and costly, the report says.

Climate change's assorted harms "are expected to become increasingly disruptive across the nation throughout this century and beyond," the National Climate Assessment concluded Tuesday. The report emphasizes how warming and its all-too-wild weather are changing daily lives, even using the phrase "climate disruption" as another way of saying global warming.

Still, it's not too late to prevent the worst of climate change, says the 840-page report, which the White House is highlighting as it tries to jump-start often stalled efforts to curb heat-trapping gases.

However, if the nation and the world don't change the way they use energy, "we're still on the pathway to more damage and danger of the type that are described in great detail in the rest of this report," said study co-author Henry Jacoby, co-director of the Joint Program on the Science and Policy of Global Change at the Massachusetts Institute of Technology. Jacoby, other scientists and White House officials said this is the most detailed and U.S.-focused scientific report on global warming.

Read the full story here

Joint Program codirector emeritus Henry Jacoby appeared on CBC's The Lang & O'Leary Exchange to discuss the findings of the Third National Climate Assessment. Jacoby is a lead author of the report's chapter on mitigation. Watch the interview below. 

Last week, a divided court of appeals upheld what may well be the most important environmental rule in the nation's history: the Environmental Protection Agency's mercury standards. The regulation is expected to prevent up to 11,000 premature deaths, 4,700 heart attacks and 130,000 asthma attacks a year.

Critics of the mercury rule have focused on its expense. The EPA estimates it will cost $9.6 billion a year, with most of the burden falling on electric utilities. Indeed, the issue of cost is what split the court.

The Clean Air Act allows the EPA to regulate electric utilities under its hazardous air pollutants program only if it finds that such regulation "is appropriate and necessary." Focusing solely on mercury's effect on public health, the EPA made that finding.

That troubled Judge Brett M. Kavanaugh. In his dissenting opinion, he asked, quite reasonably, how the EPA could possibly conclude that regulation is "appropriate" without considering costs. He argued that it's "just common sense and sound government practice" to take account of costs as well as benefits.

But the court's majority had an answer. It noted the EPA had considered costs — not in its initial decision on whether to regulate mercury emissions but in its second and crucial decision about how stringent the regulation should be. The court's majority also emphasized the benefits of the rule, which have been estimated to be worth from $37 billion to $90 billion, outweighing the costs by a factor of between 3 to 1 and 9 to 1.

For the future, the mercury controversy offers two lessons. The first is that no approach to environmental protection can afford to be indifferent to costs. In situations where Congress allows the EPA to take account of costs, the agency should do so, at least in considering the appropriate level of stringency.

The second lesson is more subtle. Calculations of the costs and benefits of a regulation should use the best available science. In the case of mercury, for example, the substance itself is a neurotoxicant, potentially affecting memory, language, attention and cognition. But it is not easy to quantify mercury's adverse effects, and the EPA did not try.

The massive benefits identified by the EPA are expected to come not from mercury reductions but from "co-benefits" — that is, from reductions in other air pollutants that will result from efforts to reduce mercury emissions.

The vast majority of the quantified benefits of the mercury rule are a product of incidental reductions in emissions of just one other pollutant: particulate matter. That's not all that surprising, given that reductions in particulate matter, which can cause serious health problems, accounted for about one-third to one-half of the total monetized benefits of all significant federal regulations from 2003 through 2012.

In coming years, the benefits of further reductions in particulate matter will be among the most contested issues in environmental regulation. No one doubts that particulate matter is harmful to human health, but we need answers to important questions about which particles are the most dangerous and how much damage they cause at low concentrations.

Increasingly, that will involve relying on so-called natural experiments to learn about the effects of pollution on health. Such experiments ask what happens to health when some practice or event (a regulatory action, for example) causes a significant, and sometimes abrupt, change in pollution for one group of people but leaves pollution unchanged for another, similar group of people.

One such study examined the health of two similar populations in China. One consisted of people who lived north of the Huai River, who received free, government-provided coal to heat their homes. The other was made up of people who lived south of the river and did not get free coal. Those heating their homes with the free coal were found to have life expectancies 5.5 years shorter than those who did not, due to the coal-generated particulate matter they inhaled.

A greater reliance on natural experiments would be an important improvement in regulatory policy. Currently, we rely on observational studies that, while informative, don't necessarily tell us what we need to know to determine a regulation's benefits. These studies compare health in places with high and low levels of pollution. But if, say, Los Angeles has higher levels of asthma than, say, Boise, Idaho, differences in the populations — such as people's socioeconomic status or health habits — rather than differences in air pollution may be responsible. Researchers try to control for those differences with rigorous statistical methods, but it is not always easy to do so.

The court's decision to uphold the EPA's mercury rule means that the American people will be able to enjoy significant health benefits. As we celebrate that decision, we should ensure that the best science is brought to bear on decisions that affect present and future occupants of the planet.

Francesca Dominici is a professor in the department of biostatistics at the Harvard School of Public Health. Michael Greenstone is a professor of environmental economics at the Massachusetts Institute of Technology. Cass R. Sunstein is a professor at Harvard Law School; he worked on the mercury rule while serving in the Obama administration from 2009 to 2012.

Yesterday, Paul Kagame, the president of Rwanda, visited MIT to discuss existing collaboration between his country and MIT, as well as to explore the possibility of broadening its scope. Kagame was traveling with Rwandan Ambassador to the United States Mathilde Mukantabana, Rwanda’s Permanent Secretary of the Ministry of Education Sharon Haba, and others of Rwanda’s leadership.

President Kagame and his delegation, together with Maria Zuber, MIT’s vice president for research and the E. A. Griswold Professor of Geophysics, and Philip Khoury, associate provost and the Ford International Professor of History, toured the laboratory of Professor Ronald Prinn, who leads the Rwanda-MIT Climate Change Observatory Project and is the TEPCO Professor of Atmospheric Science in the Department of Earth, Atmospheric, and Planetary Sciences.

Rwanda and MIT are collaborating to build a world-class observatory on Mt. Karisimbi measuring climate change and the atmospheric gases forcing climate change; the observatory is ultimately to be run by local researchers. The project evolved from discussions in 2008-2009 between President Kagame, his ministers, and the MIT administration.

Mt. Karisimbi will join the MIT-led multinational Advanced Global Atmospheric Gases Experiment (AGAGE) network that has been measuring atmospheric composition continuously over the globe since 1978. This unique new site can measure air coming from Rwanda and many other nations within and beyond Africa. Access to the 4,500-meter-high summit of Karisimbi will be facilitated by a new cable car being built for eco-tourism.

While the cable car is being built, an interim observatory has been set up on Mt. Mugogo to train the local technicians. Besides Prinn, Kat Potter, the station scientist, and doctoral student Jimmy Gasore are installing the first phase of instruments that measure temperature, winds, humidity, carbon dioxide, methane, carbon monoxide, ozone, and nitrous oxide. The second phase involves an automated mass spectrometer measuring over 50 other greenhouse gases and air pollutants. Rwandan researchers will gain the capability using computer codes to calculate regional greenhouse gas sources and sinks, climate change, and air pollution. The observatory data will be used for University of Rwanda student thesis projects, and Prinn is working with Rwandan faculty on a new Atmospheric and Climate Science master’s degree and undergraduate courses.

Rwanda will gain local capacity to adapt to climate change using the capability to forecast regional and local climate change to address the needs of local decision-makers; take advantage of revenue-yielding opportunities to mitigate climate change (such as reforestation and renewable energy using greenhouse gas sources and sink estimates); and grow a scientifically and technically educated work force that can address other important local and regional environmental and economic development issues.

Following the lab tour, Kagame and his delegation were received by MIT President L. Rafael Reif and Professor Zuber. Reif and Zuber were joined by leadership from parts of MIT that have active engagement or interest in Rwanda: the Jameel Poverty Action Lab (J-PAL); MIT D-Lab; and the MIT Energy Initiative (MITEI); and EAPS. In beginning the round-table discussion, Reif told Kagame and the rest of the meeting participants that an exploration of possibilities for new or enhanced collaboration would best center on three areas that bear directly on the well-being of Rwandans: the environment; online learning; and innovation and entrepreneurship.

MIT participants updated Kagame on current and possible engagements. Tavneet Suri, the Maurice F. Strong Career Development Professor and an associate professor of applied economics at the MIT Sloan School of Management, is the scientific director for Africa for J-PAL. She reminded Kagame of meetings held last year between J-PAL and Rwandan governmental ministers, and she described progress made on engagements currently under way; they include an effort to prevent HIV among adolescent girls, as well as work on a water-tank project. J-PAL is also helping Rwanda to build capacity for its senior civil servants and academics.

Robert Armstrong, the director of MITEI and the Chevron Professor of Chemical Engineering, provided an overview of MITEI’s work; he emphasized possibilities around solar research and work being done at MIT to explore how to provide energy for villages through the establishment of “microgrids.”

Kofi Taha, associate director of D-Lab, described the work of D-Lab and its focus on collaborating intensely with people to develop, side-by-side, the tools they need in order to improve lives. He expressed the hope that D-Lab might be helpful to the Rwandan government’s “Vision 2020,” an effort to transform Rwanda into a middle-income, knowledge-based economy by the year 2020.

Esther Duflo, the Abdul Latif Jameel Professor of Poverty Alleviation and Development Economics in the Department of Economics and founder and director of J-Pal, discussed the potential of online learning tools for teaching development economics and other subjects to those working to effect change. President Reif pointed out that though there are only a handful of Rwandan students at MIT, 1,700 Rwandans are taking courses through edX, the online learning platform founded by MIT and Harvard University.

President Kagame spoke of his desire to connect the discrete projects currently under way between MIT and Rwanda and to identify a clear set of further areas for collaboration, with Haba leading future discussions on behalf of his administration, and with the close involvement of the University of Rwanda. At the close of the meeting, Reif and Kagame agreed that the discussion showed good potential for greater collaboration.