News and Outreach: Amanda Giang

Over 300,000 babies every year are born in the United States with levels of mercury that put them at risk of neurological and developmental problems. How much would you be willing to spend to reduce this number?

MIT attendees of COP21 share experiences, perspectives on outcomes

Benefits from international regulations may double those of domestic policy

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

	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. 

Keeley Rafter
Engineering Systems Division

Noelle Selin, assistant professor of engineering systems and atmospheric chemistry, along with Amanda Giang (Technology and Policy Program graduate) and Shaojie Song (Department of Earth, Atmospheric and Planetary Sciences PhD student), recently traveled aboard the specialized NCAR C-130 research aircraft as part of a mission to measure toxic pollution in the air.

The team participated in the Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks (NOMADSS) project. The NOMADSS project integrates three studies: the Southern Oxidant and Aerosol Study (SOAS), the North American Airborne Mercury Experiment (NAAMEX) and TROPospheric HONO (TROPHONO). Selin’s group focuses on the mercury component.

“Mercury pollution is a problem across the U.S. and worldwide,” Selin says. “However, there are still many scientific uncertainties about how it travels from pollution sources to affect health and the environment.”

Selin and her students used modeling to inform decisions about where the plane should fly and to predict where they might find pollution. Their collaborators at the University of Washington aboard the aircraft captured and measured quantities of mercury in the air, conducting a detailed sampling in the most concentrated mercury source region in North America.

“It was really exciting to experience first-hand how measurements and models could support each other to address key uncertainties in mercury science,” Giang says.

The main objectives of this project include constraining emissions of mercury from major source regions in the United States and quantifying the distribution and chemical transformations of mercury in the troposphere.

NOMADSS is part of the larger Southeast Atmosphere Study (SAS), sponsored by the National Science Foundation (NSF) in collaboration with the National Oceanic and Atmospheric Administration, the U.S. Environmental Protection Agency and the Electric Power Research Institute. This summer, the Southeast Atmosphere Study brought together researchers from more than 30 universities and research institutions from across the U.S. to study tiny particles and gases in the air from the Mississippi River to the Atlantic Ocean, and from the Ohio River Valley to the Gulf of Mexico. The study aims to investigate the relationship between air chemistry and climate change, and to better understand the climate and health impacts of air pollution in the southeastern U.S.