News & Media: Earth Systems

Jennifer Chu | MIT News Office

Once mercury is emitted into the atmosphere from the smokestacks of power plants, the pollutant has a complicated trajectory; even after it settles onto land and sinks into oceans, mercury can be re-emitted back into the atmosphere repeatedly. This so-called “grasshopper effect” keeps the highly toxic substance circulating as “legacy emissions” that, combined with new smokestack emissions, can extend the environmental effects of mercury for decades.

Now an international team led by MIT researchers has conducted a new analysis that provides more accurate estimates of sources of mercury emissions around the world. The analysis pairs measured air concentrations of mercury with a global simulation to calculate the fraction of mercury that is either re-emitted or that originates from power plants and other anthropogenic activities. The result of this work, researchers say, could improve estimates of mercury pollution, and help refine pollution-control strategies around the world.

The new analysis shows that Asia now releases a surprisingly large amount of anthropogenic mercury. While its increased burning of coal was known to exacerbate mercury emissions and air pollution, the MIT team estimates that Asia produces more than double the mercury emissions previously estimated.

Noelle Selin, the Esther and Harold E. Edgerton Career Development Associate Professor in MIT’s Institute for Data, Systems, and Society and the Department of Earth, Atmospheric and Planetary Sciences, says the new analysis can also give scientists a better idea of how long legacy emissions — mercury re-emitted by the land and ocean — stick around in the atmosphere. This is because the analysis can more accurately calculate the total amount emitted by land and ocean sources.

“The timescale under which mercury circulates in the environment tells us about how fast we’ll recover if we limit mercury emissions,” Selin says. “We can better quantify mercury cycling with this method.”

Selin and Shaojie Song, a graduate student in EAPS, have published their results in the journal Atmospheric Chemistry and Physics.

Top-down approach

The team’s analysis improves on other models that take a bottom-up approach. Such models estimate mercury emissions for a region by considering factors such as the amount of coal burned in a power plant and the types of equipment in a plant used to control emissions. Models then often extrapolate data from a few sources to apply to an entire region.

However, there are a number of uncertainties with such bottom-up modeling, and it’s often difficult to obtain the required data from individual power plants.

Instead, Selin and Song’s analysis takes a top-down approach, combining bottom-up estimates with actual measurements of mercury emissions from monitoring stations around the world.

In their analysis, the team took bottom-up estimates of mercury emissions from a 2010 emissions inventory by the United Nations — a frequently used source of estimated anthropogenic emissions around the world. The researchers plugged these emissions into a global mercury transport model called GEOS-Chem — a model originally developed by Selin that has since been used widely to track how mercury circulates through the land, ocean, and air.

The GEOS-Chem model essentially divides the atmosphere into many small boxes. After plugging in bottom-up estimates of mercury emissions, the researchers ran the model to simulate the chemical and physical processes that act to circulate mercury within and between boxes. They then obtained actual measurements of mercury emissions taken from monitoring stations around the world. They compared each station’s measurements with the model’s estimates for the corresponding box in which the station was located.

“We can definitely see some differences, which tells us the [bottom-up] emissions may be wrong in some places,” Song says.

Assessing policy levers to address mercury

For locations where the measured and modeled emissions did not match up, the group used a Bayesian inversion method — a mathematical probability theory that combines observations with prior knowledge to model uncertainty. With this method, Selin and Song determined, for each station’s location, the quantitative contribution of mercury sources that would make up the total measured concentrations. For example, a location in the middle of the ocean, far from any terrestrial sources, is more likely to see mercury emissions that are re-emitted from the ocean, rather than from terrestrial or anthropogenic sources. Then, in a first application of these techniques to global mercury concentrations, they used this quantitative approach to calculate what measured concentrations implied about their sources.

By their calculations, the researchers estimated that, worldwide, Asia could produce up to 1,770 tons of mercury emissions per year — more than twice the amount estimated by bottom-up models.

“It was higher than we expected,” Selin says. “Given the pollution in China and India and increased use of coal, it does make sense. It wasn’t an out-of-the-ballpark result, but it does give you some pause to think about how much mercury could be coming out of Asia.”

In related work published this spring, Selin’s research group assessed how a new U.N. treaty could affect future mercury emissions from coal-fired power plants in Asia. They concluded that future emissions controls would have both global and domestic benefits.

In their more recent top-down analysis, the team also found that fewer mercury emissions came from terrestrial sources, meaning the land re-emitted a smaller amount of legacy emissions than expected — a small silver lining in a world of continuing mercury pollution, according to Selin.

“That means that legacy mercury is a smaller fraction of present-day mercury emissions than we thought, which means that the policy lever for addressing mercury pollution through controlling current emissions is slightly larger,” Selin says. “You still have to worry a lot about legacy emissions, but we could recover a bit more quickly because they are a smaller fraction of the total.”

This research was funded, in part, by the National Science Foundation.

by Jennifer Chu | MIT News Office

Oceans have absorbed up to 30 percent of human-made carbon dioxide around the world, storing dissolved carbon for hundreds of years. As the uptake of carbon dioxide has increased in the last century, so has the acidity of oceans worldwide. Since pre-industrial times, the pH of the oceans has dropped from an average of 8.2 to 8.1 today. Projections of climate change estimate that by the year 2100, this number will drop further, to around 7.8 — significantly lower than any levels seen in open ocean marine communities today.

Now a team of researchers from MIT, the University of Alabama, and elsewhere has found that such increased ocean acidification will dramatically affect global populations of phytoplankton — microorganisms on the ocean surface that make up the base of the marine food chain.

In a study published today in the journal Nature Climate Change, the researchers report that increased ocean acidification by 2100 will spur a range of responses in phytoplankton: Some species will die out, while others will flourish, changing the balance of plankton species around the world.

The researchers also compared phytoplankton’s response not only to ocean acidification, but also to other projected drivers of climate change, such as warming temperatures and lower nutrient supplies. For instance, the team used a numerical model to see how phytoplankton as a whole will migrate significantly, with most populations shifting toward the poles as the planet warms. Based on global simulations, however, they found the most dramatic effects stemmed from ocean acidification.

Stephanie Dutkiewicz, a principal research scientist in MIT’s Center for Global Change Science, says that while scientists have suspected ocean acidification might affect marine populations, the group’s results suggest a much larger upheaval of phytoplankton — and therefore probably the species that feed on them — than previously estimated.

“I’ve always been a total believer in climate change, and I try not to be an alarmist, because it’s not good for anyone,” says Dutkiewicz, who is the paper’s lead author. “But I was actually quite shocked by the results. The fact that there are so many different possible changes, that different phytoplankton respond differently, means there might be some quite traumatic changes in the communities over the course of the 21st century. A whole rearrangement of the communities means something to both the food web further up, but also for things like cycling of carbon.”

The paper’s co-authors include Mick Follows, an associate professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences.

Winners and losers

To get a sense for how individual species of phytoplankton react to a more acidic environment, the team performed a meta-analysis, compiling data from 49 papers in which others have studied how single species grow at lower pH levels. Such experiments typically involve placing organisms in a flask and recording their biomass in solutions of varying acidity.

In all, the papers examined 154 experiments of phytoplankton. The researchers divided the species into six general, functional groups, including diatoms, Prochlorococcus, and coccolithophores, then charted the growth rates under more acidic conditions. They found a whole range of responses to increasing acidity, even within functional groups, with some “winners” that grew faster than normal, while other “losers” died out.

The experimental data largely reflected individual species’ response in a controlled laboratory environment. The researchers then worked the experimental data into a global ocean circulation model to see how multiple species, competing with each other, responded to rising acidity levels.

The researchers paired MIT’s global circulation model — which simulates physical phenomena such as ocean currents, temperatures, and salinity — with an ecosystem model that simulates the behavior of 96 species of phytoplankton. As with the experimental data, the researchers grouped the 96 species into six functional groups, then assigned each group a range of responses to ocean acidification, based on the ranges observed in the experiments.

Natural competition off balance

After running the global simulation several times with different combinations of responses for the 96 species, the researchers observed that as ocean acidification prompted some species to grow faster, and others slower, it also changed the natural competition between species.

“Normally, over evolutionary time, things come to a stable point where multiple species can live together,” Dutkiewicz says. “But if one of them gets a boost, even though the other might get a boost, but not as big, it might get outcompeted. So you might get whole species just disappearing because responses are slightly different.”

Dutkiewicz says shifting competition at the plankton level may have big ramifications further up in the food chain.

“Generally, a polar bear eats things that start feeding on a diatom, and is probably not fed by something that feeds on Prochlorococcus, for example,” Dutkiewicz says. “The whole food chain is going to be different.”

By 2100, the local composition of the oceans may also look very different due to warming water: The model predicts that many phytoplankton species will move toward the poles. That means that in New England, for instance, marine communities may look very different in the next century.

“If you went to Boston Harbor and pulled up a cup of water and looked under a microscope, you’d see very different species later on,” Dutkiewicz says. “By 2100, you’d see ones that were living maybe closer to North Carolina now, up near Boston.”

Dutkiewicz says the model gives a broad-brush picture of how ocean acidification may change the marine world. To get a more accurate picture, she says, more experiments are needed, involving multiple species to encourage competition in a natural environment.

“Bottom line is, we need to know how competition is important as oceans become more acidic,” she says.

This research was funded in part by the National Science Foundation, and the Gordon and Betty Moore Foundation.

By David L. Chandler | MIT News Office

According to present plans, the Grand Ethiopian Renaissance Dam (GERD) — now under construction across the Blue Nile River in Ethiopia — will be the largest hydroelectric dam in Africa, and one of the 12 largest in the world. But controversy has surrounded the project ever since it was announced in 2011 — especially concerning its possible effects on Sudan and Egypt, downstream nations that rely heavily on the waters of the Nile for agriculture, industry, and drinking water.

To help address the ongoing dispute, MIT’s Abdul Latif Jameel World Water and Food Security Laboratory (J-WAFS) convened a small, invitation-only workshop of international experts last November to discuss the technical issues involved in the construction and operation of the dam, in hopes of providing an independent, impartial evaluation to aid in decision-making. The group’s final report, which was shared with the three concerned governments in early February, is being released publicly today.

On March 23, the three governments signed an agreement to enter negotiations for final settlement of issues surrounding the dam’s operations. Though the agreement is preliminary, it marks a significant step forward.

Professor John H. Lienhard V, the director of J-WAFS, was among the organizers of the November workshop held at MIT. He says that the group was carefully selected to include top experts on water resources engineering and economics and on the Nile Basin, and was charged with reviewing the current state of technical knowledge on the GERD and its potential downstream impacts. The idea was “to give advice, and do it impartially,” Lienhard says.

“We went out of our way to find people who know about large dams and large rivers, and who are not affiliated with any of the three governments,” including people with “hands-on experience with dams of this scale,” Lienhard says. The meeting also included observers from Egypt, Sudan, and Ethiopia. After the report was shared, members of the group also met with officials in Egypt and Ethiopia to review the technical issues.

Technical issues

The working group developed consensus recommendations, which were incorporated into the 17-page report. It reflects agreement reached at the November workshop, says Lienhard, who is also the Abdul Latif Jameel Professor of Water and Food at MIT.

The report raises five technical issues that require resolution. First, the GERD will join the Aswan High Dam as a second large reservoir on the Nile River. Egypt and Ethiopia need to formulate a plan for coordinating the operation of these two dams, so as to equitably share Nile waters during periods of reservoir-filling and prolonged drought. Nowhere in the world are two such large dams on the same river operated without close coordination.

Second, the design of the GERD requires that a very large “saddle dam” be built to prevent water stored behind the GERD from spilling out of the northwestern end of the reservoir. The risks associated with a possible failure of this saddle dam may not have been fully appreciated, and must be carefully managed.

Third, there is concern about the location and capacity of the GERD’s low-level release outlets to provide water to Egypt and Sudan during the reservoir’s filling or periods of drought.

Fourth, the hydropower generated from the GERD exceeds Ethiopia’s current domestic power market, and it will therefore need to be sold outside Ethiopia. A plan is needed for such sales, and for the construction of transmission lines to regional markets. A power trade agreement will ensure that the Ethiopian people receive a good financial return on their investment.

Fifth, the ongoing accumulation of salts in the agricultural lands of the Nile Delta could accelerate rapidly; additionally, the GERD will enable Sudan to increase irrigation withdrawals upstream, further reducing the water available to Egypt. Studies are urgently needed to identify the magnitude of these potential problems, and to mitigate their impact.

Managing the flow

Perhaps the biggest question concerning the new dam is how Ethiopia will manage the process of filling its huge reservoir, whose capacity equals more than a year’s flow of the Blue Nile. Egypt has expressed concerns that if the reservoir is filled too quickly, it could severely diminish the flow upon which Egypt depends; 60 percent of the nation’s water comes from the Blue Nile.

“The Egyptians are very concerned about what a reduction in the amount of water would mean to them,” says Kenneth Strzepek, a research scientist at MIT’s Joint Program on the Science and Policy of Global Change, and a co-chairman of the November workshop.

Dale Whittington, a professor at the University of North Carolina and a co-editor of the MIT report, says: “Egypt, Ethiopia, and Sudan are currently hoping that a team of international consultants can quickly find technical solutions to these challenging problems to which they can agree. From our perspective, this is likely wishful thinking. The hard negotiations ahead will require that foreign policy and water experts from each of the three countries have a shared understanding of the technical issues and a willingness to compromise while hammering out detailed agreements on reservoir operation policy, power trade agreements, dam safety, and salinization control.”

But, Whittington says, “A shared knowledge base and modeling framework is unfortunately lacking, despite over $100 million in investment by the Nile Basin Initiative over more than a decade of engagement.”

Don Blackmore, former executive director of the Murray-Darling River Basin Authority in Australia and current chair of the International Water Management Institute, says, “Egypt, Sudan, and Ethiopia will try to work with their consultants to solve these five problems, but if these countries request assistance, we believe that the international community has an obligation to step forward.”

Other nations can potentially play three roles, says Blackmore, who was not involved in compiling the new report: providing impartial scientific advice; bringing legal expertise and experience on transboundary waters to help craft the text of technical agreements; and serving to arbitrate disputes that arise over time.

Given the potential for conflict among the nations dependent upon this water, Blackmore adds, “The international community needs to focus on the Nile as a matter of urgency.”

By Cassie Martin | Oceans at MIT

Earlier this year, weather and climate agencies around the world declared 2014 the warmest year on record, even though the increase in global mean temperature has slowed. This warming “hiatus” has puzzled climate scientists, as it deviates from climate models which project a continuing temperature increase. Climate expert Jochem Marotzke visited MIT last week to deliver the 15^th annual Henry W. Kendall Memorial Lecture “Recent Global Temperature Trends: What do they tell us about anthropogenic climate change?” in which he discussed the hiatus as well as the abilities and limitations of climate models.

Marotzke is a director at the Max Planck Institute for Meteorology in Hamburg, Germany, and was an MIT EAPS faculty member in the 1990s. He has spent his career researching the role of the ocean in climate and climate change, and recently expanded his interests to include multi-year to decadal climate prediction. “If you look at other central indicators of global climate, such as sea ice melt, ocean heat uptake, and sea-level rise, they show that global warming is continuing,” Marotzke said. “But this particular indicator, global surface temperature, is rising at a much lower rate now. This is something that as a climate research community we need to take seriously; we need to understand it and communicate the issues about it.”

For the past 15 years, increases in global mean surface temperature has slowed contrary to what climate model simulations predicted. Known as the warming “hiatus”, this phenomenon is largely due to natural variability: Cyclical climate processes such as La Niña and fluctuations in the amount of solar radiation reaching Earth’s surface can disrupt the warming trend. Additionally, the oceans absorb an enormous amount of excess heat energy trapped by the atmosphere—as much as 93 percent, Marotzke said. Light-reflecting aerosols from volcanoes also contribute to the slow down.

The failure of climate models to predict this hiatus has long perplexed scientists and bred some public mistrust in climate models. Climate change skeptics claim the hiatus is proof that global warming doesn’t exist, and that climate models overestimate greenhouse gases’ warming effects. Marotzke ardently disagrees. He shared with the audience a study published in Nature earlier this year in which he and co-author Piers Forster of the University of Leeds analyzed 114 model simulations of 15-year global mean temperature trends since the beginning of the 20^th Century. If their analysis showed that models consistently overestimated or underestimated the amount of warming compared to real-world observations, then the models must have a systematic bias.

Fortunately the simulations performed fairly well, producing a range of predictions for each 15-year period in which actual observed temperature trends for those periods fell. Even if the observed trends at times fell close to range edges, they were not biased to one side or the other. Although the models didn’t accurately predict the current warming hiatus, which is not unusual, they also failed to predict other accelerated warming or hiatus events. In fact, the models underestimated warming in some periods compared to the observations. “The claim that models systematically overestimate warming from increasing greenhouse gas concentrations is unfounded,” said Marotzke.

To find out what these simulated short-term temperature trends actually tell us about the climate, Marotzke and Forster performed a multiple regression analysis, which aimed to identify the most significant factors contributing to the trend. For shorter 15-year periods, the analysis found random natural variability in the climate system had the largest influence—approximately three times the impact of all other physical factors combined. Only when Marotzke and Forster analyzed model simulations of global mean temperature trends spanning 62 years did differences in factors including ocean heat absorption, greenhouse gas concentration, and aerosol pollution begin to make a noticeable difference.

In other words, modeling 15-year-long periods only shows the impact of natural variations in the climate system. To see anthropogenic influences on climate change, we have to look at the bigger picture. “The hiatus masks anthropogenic warming,” said Marotzke. “It is a huge distraction, but an incredibly fascinating one.”

The 15th Annual Henry W. Kendall Memorial Lecture was sponsored by the MIT Department of Earth, Atmospheric and Planetary Sciences and the MIT Center for Global Change Science. The lecture series honors the memory of Professor Henry Kendall (1926-1999), a 1990 Nobel Laureate, a longtime member of MIT’s physics faculty, and an ardent environmentalist. A founding member and chair of the Union of Concerned Scientists, he played a leading role in organizing scientific community statements on global problems, including the World Scientists’ Warning to Humanity in 1992 and the Call for Action at the Kyoto Climate Summit in 1997.

Watch the full lecture here.

The Minamata Convention on Mercury, adopted by the UN in 2013, aims to reduce global mercury pollution by setting limits on specific pollution sources and prohibiting new mercury mining. Certain aspects of the treaty are still under negotiation, for instance the convention gives nations the flexibility to create their own plans for reducing mercury emissions from some sources, like coal-fired power plants. How nations choose to address these emissions has the potential to have a big impact on global mercury pollution, since coal fired power plants are responsible for about a quarter of mercury emissions worldwide.

MIT Engineering Systems Division graduate student Amanda Giang, a research assistant in the MIT Joint Program on the Science and Policy of Global Change, co-authored a recent study published in the journal Environmental Science & Technology that evaluates different ways India and China might address coal-fired power plants. The research was supported in part by the National Science Foundation.

Q. Why study India and China?

A. Whatever China and India do to reduce their mercury emissions will have the biggest impact on future global mercury levels. China is currently estimated to emit about a third of global emissions, and India is the second largest source at 7 percent. These emissions come from a variety of activities—mining, cement production, metal smelting—but coal combustion for industry and electricity generation is one of the biggest sources in these countries, and this source is expected to grow as economies develop.

Mercury from power plants travels worldwide, but is also deposited in ecosystems close to where it is emitted. That means countries have a strong domestic incentive to decrease mercury emissions. That is, the benefits of reduced pollution will be most strongly felt where the cuts are made, in addition to at the global level. So, a strict emissions standard for coal-fired power plants will not just benefit other countries, it would benefit India and China domestically.

Q. How do you measure the treaty’s benefits?

A. We measure benefits as avoided future mercury emissions. So we compare what would have been emitted under current pollution control technologies to what would be emitted under a few different ways of achieving the requirements outlined in the Convention, either through stricter technology requirements, or system-wide changes in the energy system. There are many technologies that can reduce mercury pollution, some already widely in use. We also model how mercury emissions travel through the atmosphere and enter ecosystems under these different scenarios.

The decisions that Convention negotiators make about the stringency of the technology requirements for coal power plants will make a big difference in avoided emissions. Convention negotiators want to strike a balance between requiring strong pollution control and allowing flexibility for different countries’ economic and technical capacities. Through analysis of existing studies, policies, and interviews with Convention negotiators, we identify technologies that India and China would be likely to adopt if they were given a lot of flexibility. We find that putting these technologies in place avoids about 12 percent of current day emissions. Requiring stronger, but technologically feasible pollution control technologies avoids another 8 percent—an amount equivalent to India’s total present-day emissions.

Q. So far you’ve covered how to avoid increases in mercury pollution. Is there any way to actually decrease emissions?

A. Emissions-control technologies can slow emissions growth, but alone, they likely won’t keep total mercury emissions from growing as China and India consume more coal to fuel their energy needs. The most effective way to lower mercury emissions below present-day levels would be combining control technologies with a transition away from coal as a power source. Under a global transition to low-carbon energy sources, we could see a decrease in emissions from the power sector. In India though, where power sector growth is anticipated to meet energy access needs, we could still see an increase in emissions in the future despite control policies.

It’s important to keep in mind that whatever mercury is released into the environment now doesn’t stay where it’s deposited. Mercury that is deposited in the environment can easily cycle through the rest of the ecosystem for decades, ending up in the air, water, and land. So, whatever decisions are made about how to reduce mercury emissions now will continue to affect us in the future.

This research was supported in part by the National Science Foundation.

Read the study
Impacts of the Minamata Convention on mercury emissions and global deposition from coal-fired power generation in Asia

Jennifer Chu | MIT News Office

Dip a beaker into any portion of the world’s oceans, and you’re likely to pull up a swirling mix of planktonic inhabitants. The oceans are teeming with more than 5,000 species of phytoplankton — microscopic plants in a kaleidoscope of shapes and sizes. Together, phytoplankton anchor the ocean’s food chain, supplying nutrients to everything from single-celled organisms on up to fish and whales.

Through photosynthesis, these tiny organisms supply more than half the world’s oxygen. When these plants die, they drift to the ocean bottom, or evaporate into the air as carbon — a process that generates more than half the world’s cycling carbon.

Phytoplankton play a fundamental role in regulating Earth’s climate. But figuring out exactly how these organisms contribute to climate change is a tricky undertaking, primarily because they are so diverse: Any given species may have a set of genetic or physical characteristics entirely different from any other, leading to different behaviors and habitats.

Such diversity can appear, at the outset, “bewilderingly complex,” says Mick Follows, an associate professor of oceanography in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). He says wrestling such diversity into global climate models is a futile task. But lumping phytoplankton into a big “black box” can be equally unenlightening.

Instead, Follows is working at an intermediary level, developing models of marine microbes at the cellular and community levels, to tease out fundamental processes that may be worked into global climate models.

“We’re starting to open up the black box of simple models,” Follows says. “There’s a balance: Do you want to understand every detail of the world, or do you want to be able to stand back and have a big picture view? Somehow you have to keep circling around it from both directions to develop that view.”

For more than 20 years, Follows has worked as a research scientist at MIT, answering such questions. He was granted tenure as an associate professor in 2013.

“I’m now interacting with undergraduates in a way I wasn’t doing in my little research hole, and I have a whole new appreciation for the broader aspects of MIT,” Follows says. “I feel much more connected to the Institute as a whole.”

An ocean of opportunity

While growing up, Follows didn’t expect he would end up in academia: School wasn’t a priority then. 

Follows grew up in a small town in the British region of East Anglia, and fondly remembers “riding bikes around the countryside, and living quite freely.”

His father was a typesetter at a local newspaper, and his mother worked in a men’s clothing shop. Both his parents have roots in Manchester — “a downtrodden, post-industrial place,” Follows says — where his mother was nevertheless able to win a scholarship to a good public school.

“She worked in shops, and in the field, but would be quoting Shakespeare,” Follows says of his mother’s path.

Follows was less inclined toward school, and ended up leaving high school. “I don’t think people think of me this way now, but I was a bit of a loudmouth,” Follows recalls.

He ultimately continued his studies at a community college, and spent a year at an art school — a fact that he’d rather overlook: “My work was rubbish — terrible!”

He then decided to pursue studies in math and physics at the University of Leeds. “I liked the organization [the subjects] brought to the world,” Follows says. While exploring graduate programs, he was particularly drawn to atmospheric science. Follows enrolled at the University of East Anglia, where he earned a master’s degree and a PhD in atmospheric sciences, studying atmospheric circulation of ozone. In his research, he began to see parallels between the atmosphere and the oceans.

“How ozone gets down from the stratosphere to troposphere, there’s an analogous process, flipped, when you think of how nutrients get from the subsurface to the surface of the ocean, and I started thinking more about the ocean,” Follows says.

In particular, Follows felt there was an opportunity to contribute to a then-emerging field. “While coupled circulation and chemistry models were established for the atmosphere, the same was just spinning up in the oceans,” Follows says. “It seemed the ocean world was a bit less crowded, and there were interesting problems.”

Follows credits his colleague John Marshall, now the Cecil and Ida Green Professor of Oceanography, for providing his path to MIT. Follows was still at the University of East Anglia when he first met Marshall, then a postdoc at Imperial College London.

“Being as I was the local guy, I said, ‘I’ll show you a place where we can go get a meal,’” Follows recalls. “I sat next to John and said, ‘Are you looking forward to going to MIT?’ And he kind of frowned as he does, and said, ‘You want to go?’”

A few weeks later, Marshall called Follows about a postdoc position opening up at Imperial College. Follows accepted the position, and then after a year, received a similar call from Marshall, this time to MIT. In 1992, Follows arrived on campus as a postdoc, and stayed for the next 20 years as a research scientist.

From a black box to the real world

At MIT, Follows has devoted his research to understanding the biological processes of phytoplankton and other microbes that contribute to the Earth’s carbon cycle. Initially, though, every microbe seemed to blur together.

He eventually teamed up with Sallie “Penny” Chisholm, the Lee and Geraldine Martin Professor in Environmental Studies at MIT, who discovered Prochlorococcus —the most abundant photosynthetic organism in the world. Chisholm was studying subpopulations of Prochlorococcus, and mapping individual communities in the ocean.

“Suddenly there was a beautiful system where organisms that are almost the same, but not quite, are taking different habitats, occupying different niches in the environment,” Follows says.

Chisholm’s data of diverse microbes stirred up an idea: What if the diversity in phytoplankton could be modeled based on natural selection? Could one predict the makeup of a microbial community, based on its inhabitants’ traits? It was a simple idea, and yet no one had attempted to realize it in global models.

Follows and his group developed a model — essentially a virtual ocean environment — in which a realistic set of microorganisms with diverse traits can interact and compete. The model determines which traits are the fittest phenotypes — the ones that will dominate in a given ocean community.

“I think that in the field, we had reached a bit of a stalemate, where you would just keep adding more parameters and tuning more knobs to fit the real world,” Follows says. “We turned around and said, ‘Let’s build a videogame — make an environment, throw some players in, ask how the system organizes itself, and acknowledge that in the real world, there is a huge diversity of organisms.’”

This radical thinking earned Follows a grant from the Moore Foundation in 2007, which he used to start the Darwin Project, a cross-campus collaboration between oceanographers, biogeochemists, and marine microbiologists at MIT to develop global ocean-circulation models built around fundamental microbial processes.

Follows is continuing to run the Darwin Project, and just recently became a member of SCOPE — the Simons Collaboration on Ocean Processes and Ecology — a five-year project based at the University of Hawaii. He and his fellow researchers will measure and model ocean communities around Hawaii, which are thought to be representative of a large swath of the North Pacific. Their goal is similar to Follows’ original vision: to elucidate how such tiny organisms can have such huge climatic impacts.

“The climate system is incredibly tied up with life,” Follows says. “You can think of man in the same way as those first photosynthetic bacteria that changed the planet in a radical way, to a completely different set of requirements if you wanted to survive on that planet. Are we that thing now? Or are we a blip? It’s interesting to put it in perspective.”

Solomon Asaba | The New Times

Researchers at Massachusetts Institute of Technology’s Centre for Global Change Science are in advanced stages to start a climate observatory centre in Rwanda, next year, with an aim of collecting atmospheric observations from the slopes of Mt. Karisimbi, a volcano located in the northwest of Rwanda. The project is spearheaded by Prof. Ron Prinn, a professor of atmospheric science, department of Earth, Atmospheric and Planetary Sciences at the university. The New Times Solomon Asaba had an interview with him.

Excerpts.

Whom are you collaborating with to start this observatory and how much has been achieved so far?

The observatory is a partnership between the Government of Rwanda and the MIT Centre for Global Change Science. We already have in place an interim observatory that has been placed on Mt. Mugogo and is operated mainly by Rwandans.

What kind of information will be obtained at the observatory and who will have access to its final site?

The observatory will measure the composition of air coming from East and South Africa as well as the Middle East and India.

The final site for the observatory is the summit of Mt. Karisimbi. When the Cable Car for ecotourism is complete, all scientists will be in position to access this summit.

How will Rwandans benefit from this kind of modern facility?

If the observatory is successful, it will help educate Rwandans interested in atmospheric science. It will join the Advanced Global Atmospheric Gases Experiment (AGAGE), a global network measuring greenhouse gases and other climate driving agents. Rwandans are already on their way to running the observatory.

Read the full article at the New Times.

By Angela Fritz | The Washington Post

Late last week, one of the strongest tropical cyclones on record in the South Pacific made a direct hit on the island nation of Vanuatu, leaving more than 20 people dead and massive destruction in its wake.

Tropical Cyclone Pam’s sustained winds of 165 mph and gusts nearing 200 ripped trees from the ground and flattened homes. In the course of a day, Tropical Cyclone Pam intensified from the equivalent of a category 2 hurricane to a category 4, before going on to become just the second category 5 on record to directly hit an island in the South Pacific. At the time, Pam was the strongest of four concurrent cyclones in the western Pacific and Indian oceans.

It was “one of the largest and most intense cyclones” the region has seen, says Greg Holland, a senior scientist at the National Center for Atmospheric Research who has specialized in South Pacific tropical storms. “Taken together I have not seen a storm with higher damage potential in the region,” Holland told The Washington Post, “and this shows in the extensive damage that Vanuatu has suffered.”

Now, as the death toll grows and the people of Vanuatu pick up the pieces of their devastated lives, scientists are pondering what role Earth’s changing climate may have had in the destructive potential of the storm.

In a post on the climate science blog RealClimate, MIT meteorologist Kerry Emanuel dissects the science embodied in the question, coming to the conclusion that “while Pam and Haiyan, as well as other recent tropical cyclone disasters, cannot be uniquely pinned on global warming, they have no doubt been influenced by natural and anthropogenic climate change and they do remind us of our continuing vulnerability to such storms.”

Read the full article on the Washington Post

by Kelsey Damrad | MIT Department of Civil and Environmental Engineering

As severe weather hazards continue to afflict parts of the country to historic extremes, Professor Dara Entekhabi of the MIT Department of Civil and Environmental Engineering (CEE) and a team of NASA scientists provide an unprecedented resource to accurately observe moisture levels within the land for more precise prediction of weather and climate.

On March 4, Entekhabi and NASA’s Soil Moisture Active Passive (SMAP) satellite successfully completed the initial test of its science instruments and revealed its very first image of the Earth’s soil moisture. These “first-light” images were composed of tiny slivers of data in a 40-kilometer line scan and revealed details about the Earth’s soil moisture levels.

During this test, Entekhabi explains, the satellite is not spinning as it orbits the Earth pole-to-pole. As a result, it images a narrow footprint on the ground. Later in March, when the satellite begins to spin as it orbits, the ground footprint will not only have higher resolution but it will also cover a 1,000-kilometer-wide swath.

Specific elements outlined in these early images included a defined contrast between land and ocean bodies. This, says Entekhabi, is a test of the geolocation accuracy. Also over Antarctica, the distinction between ocean, ice shelf, and land ice were clearly evident. Over land, the scattering signature of regions with high biomasses palpably distinguished the sensitivity of the instruments with these early data. For example, the Amazon and Congo forests showed high radar echoes.

“This is just a tiny snapshot of SMAP’s capabilities,” Entekhabi says. “What we are seeing, even in a 40-kilometer line scan, is really remarkable.”

Additionally, the images detected evidence from a variety of known weather phenomena on the ground including Cyclone Marcia — a Category 5 tropical cyclone that occurred in Australia on Feb. 20. This cyclone’s footprint was illustrated in SMAP’s image through low brightness temperatures, a result of its high moisture content in the soil from heavy rainfall.

According to Entekhabi, the amount of accurate data received from SMAP in such an early stage is unparalleled by any other satellite mission.

“Where we are today, with just two days of data, is where other missions are after two years,” said Entekhabi. “Two other existing satellites, SMOS from Europe and Aquarius from NASA, took two years to come to the same calibration accuracy that we saw without any calibration at all.”

An Earth-monitoring mission initiated in late 1999, SMAP is designed to provide a global map of the moisture content of topsoil and provide meteorologists with a resource to better predict severe weather hazards such as heavy precipitation, floods, droughts, hurricanes, and wildfires.

The satellite is now being maneuvered into its final science orbit, which will take an estimated two weeks.

Reflector antenna unfurled Feb. 24

NASA mission controllers successfully deployed SMAP’s 6-meter-wide reflector antenna on Feb. 24 — a significant milestone in the estimated three-year satellite expedition. To unfurl it, NASA sent commands to the observatory to fire an onboard pyro that would release the stowed antenna, which ultimately engaged the motors and expanded the umbrella-like antenna.

Both the radiometer and radar were activated for a two-day period, during which Entekhabi and his team downloaded detailed data from the satellite and assessed the overall instrument performance. SMAP's science instruments and the deployed reflector antenna, in a non-spinning configuration, underwent their initial operation to view Earth.

Made of a lightweight mesh material, the reflector is the satellite’s preliminary step in its overall mission to provide global soil moisture maps.

“Both the radar and the radiometer performed absolutely flawlessly and beyond the team’s expectations,” he says. “The satellite was only on for 48 hours, and the team was able to process that very limited data all the way through the data systems. This is a testament to the preparedness of the mission team and the motivation to do it so quickly.”

On March 31, the mission controllers will perform their final science configuration by releasing the clutch that holds the satellite’s antenna in place and allow for the satellite spin as it orbits to start. The satellite will then have the ability to scan approximately 1,000 kilometers (620 miles), as opposed to exclusively visualizing the area directly beneath the spacecraft.

According to Entekhabi, this instrumental global soil moisture data acquired by the satellite will also allow scientists to gain a comprehensive understanding of the interconnected nature of Earth's three major cycles: water, carbon, and energy.

“We want a global perspective on the Earth’s water cycle in order to understand how the environment works as well as some of the applications that touch our every day lives,” said Entekhabi. “We want to bring the technical capability to sense the environment to the same level as medical imaging.” SMAP is an embodiment of the lessons taught behind the CEE doors, he continued.

SMAP’s science operations will commence the beginning of May, and provide a high-resolution map of the globe’s soil moisture every two to three days.