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ILP Institute Insider

December 12, 2016

On Addressing Global Change Science

Ron Prinn directs MIT's Center for Global Change Science and co-directs its Joint Program on the Science and Policy of Global Change. Among other things these groups are running the Advanced Global Atmospheric Gases Experiment which measures greenhouse gases and ozone-depleting gases using high frequency measurements.

Bernadette Esposito

Ron Prinn directs MIT’s Center for Global Change Science (CGCS) and co-directs its Joint Program on the Science and Policy of Global Change. Under the CGCS, the Advanced Global Atmospheric Gases Experiment (AGAGE) project has been, since its inception in 1978, the first to make and use high frequency measurements to accurately determine the sources and the sinks of greenhouse gases and ozone-depleting gases.

The general public, says Prinn, may not realize that besides carbon dioxide and methane, a large group of purely synthetic gases are becoming a bigger and bigger fraction of the total climate forcing by greenhouse gases. One recent AGAGE study looking at the top 25 of these purely synthetic greenhouse gases determined that the concentrations of chlorofluorocarbons are going down in concert with the Montreal Protocol, while the concentrations of other synthetic greenhouse gases including hydrofluorocarbons which sit in car air conditioners, and sulfur hexafluoride, an electrical insulator contained in high-voltage circuit breakers, are increasing. “If we continue to have these rising for the next several decades, then they are going to be a bigger player than methane in forcing climate change.”

Ron Prinn
TEPCO Professor,
Atmospheric Science
and Director,
Center for Global Change and Science

These synthetic greenhouse gasses, along with all of the major greenhouse and ozone depleting gases, are measured in real time on site at twelve climate observatories around the world. Sponsored by NASA, the AGAGE climate stations take 20-36 measurements daily. Some stations, like the one in Samoa, where there are no significant nearby sources of greenhouse gases, measure background air as a baseline. Other stations, like the one in Ireland, measure both the relatively clean air that comes off the Atlantic Ocean, as well as the polluted air that has gone into Europe and come back out again over the station. The air coming off Europe has high levels of man-made gases. “The difference between what went in and what comes out signals the amount of emissions that have occurred in Europe. And, similarly, for almost all of the other stations,” says Prinn. To interpret the measurements, complex computer models have been made. “By adjusting the sources and sinks in these models, we force them to agree with the observations we’re taking. At that point we have an estimate of sources and sinks, an approach we use for each of the fifty-plus gases we measure.”

Until 2008 when discussions between the president of Rwanda and the president of MIT began, there was no high-end AGAGE station in the whole continent of Africa. Because Rwanda is already experiencing significant warming and will continue to over the course of the next century, Prinn says the country needs to prepare for climate change to minimize damages. The observatory was proposed by CGCS as one of the projects that, if built in Rwanda, would automatically produce world class science, specifically to help address the “data challenge” in Africa and generate long-term calibrated climate measurements. The observatory was also designed to help keep “the best brains in Africa.” Prinn says students there typically get their doctoral degrees in Europe or the United States where, for lack of options back home in Africa, they then stay. The observatory was also designed to address that. To give an example of capacity-building, Prinn offers the case of a current doctoral student, a graduate of the University of Rwanda, who is doing his MIT doctoral thesis in EAPS measuring carbon dioxide and methane in Rwanda and estimating African emissions of these gases. “Once he’s got his PhD, he will very likely become the first Rwandan Director of the new Climate Observatory there.”

Joint Program on the Science and Policy of Global Change
Some of the same science-based principles of the AGAGE network, but on a much larger and diverse scale, are at work in the Joint Program on the Science and Policy of Global Change. Founded in 1991 to work with industries and federal agencies like DOE on better understanding climate change, ozone depletion, and other environmental issues, it is, as Prinn describes, “a remarkable collaboration between economists, environmental scientists, and people who understand energy and agricultural technologies.” The Joint Program makes probabilistic predictions of economic and environmental change, identifies risks, and illuminates actions to lower those risks. The overall goal is to provide a better science basis for decision-making in the public & private sectors. Specific objectives include examining economic and environmental implications of new energy technologies at large scale (e.g. wind, solar, nuclear, carbon capture and storage and biofuels), and understanding connections among climate, air pollution, food, water, energy, land use and urbanization.

Integrated Global Systems Model
Addressing these goals and objectives required a massive and unique new computer program that intimately coupled models of the human and natural earth systems. Thus, the central research tool for the Joint Program on the Science and Policy of Global Change, called the Integrated Global System Model (IGSM), is a detailed economics model coupled with an equally detailed environmental model that includes climate, air pollution, and water quality and quantity. “We began to build it in 1991 and it required us to form a team of now around forty people that cover all the relevant disciplines: economics of various countries around the world; industrial development; energy production and use; agricultural production and consumption; water quality and quantity; and then, of course, all the climate and air pollution implications of producing various goods and services.” All of these are incorporated into a large complex computer model that’s run on a very big cluster at MIT. Prinn says it’s unique in that it not only models all of the big economies of the world and the trading among them, but also models in great detail all of the ways we produce goods like energy and agricultural products now, and are likely to produce them in the future.

Nearly thirty big energy companies, electric utilities, agricultural companies like Cargill and Weyerhaeuser, and apparel producers like Nike help support the Joint Program, all of them concerned with making decisions that take into account both economic and environmental change. “Some are concerned with deciding what mix of technologies will dominate future energy production while lowering climate change risks, while others are looking at the lowest cost way to lower specific greenhouse gas emissions or the sourcing of the materials they use in manufacturing their products,” Prinn notes. These companies, lacking the needed big in-house teams that understand the economics and the science of these complex intertwined issues, use the Joint Program results to provide the needed science-based information for their decision-making.

Finally, there are direct connections between the Joint Program and AGAGE. The IGSM is calibrated to agree with current and past measurements of greenhouse gases (including AGAGE) and climate change. And the IGSM can incorporate existing and proposed new regulations to address their costs and effectiveness. The rising synthetic greenhouse gases observed in AGAGE present a new challenge that has led recently to inclusion of the aforementioned hydrofluorocarbons into the Montreal Protocol. “It’s not that these synthetic chemicals are bad, intrinsically,” says Prinn; “it’s when they’re released into the atmosphere in large amounts, that problems arise. For example, the gas nitrogen trifluoride that is produced during the manufacture of flat screen television displays can be removed simply by incineration or recycled locally. Another smart thing companies can do in their research labs is to find and produce alternatives. This happened when the big companies that were manufacturing the chlorofluorocarbons found that there were safer replacements. As a result, the chemical industry did not oppose the Montreal Protocol. They just said, ‘We’ve got alternatives’.”