Water Scarcity, Air Pollution and Climate Change Mark Dwortzan | MIT Joint Program Monday, December 12, 2016

On December 12-16, several MIT CGCS and Joint Program researchers and affiliates plan to share recent findings at the American Geophysical Union’s (AGU) 2016 Fall Meeting in San Francisco, the largest Earth and space science conference in the world. Drawing about 24,000 attendees last year, the conference showcases the latest discoveries, trends and challenges in the field. CGCS and Joint Program-led talks and posters will explore the future of global water resources, air pollution and climate change, using model projections to assess where the planet is heading under different policy scenarios.

Many of the 17 talks and posters highlighted below are collaborations among multiple Joint Program and CGCS researchers and coauthors from other institutions. While only the lead author is specified in most cases, coauthors are listed in each of the linked abstracts. 

Water scarcity 

In an invited talk, “Confronting Future Risks of Global Water Stress and Sustainability: Avoided Changes Versus Adaptive Actions,” CGCS Senior Research Scientist and Joint Program Deputy Director C. Adam Schlosser will chart the future of global water resources under a range of plausible scenarios for socioeconomic development and climate change. The talk will underscore the importance—and potential cost savings—of global adaptive measures needed to meet surface-water shortfalls even under highly aggressive climate mitigation pathways.

“Globally speaking, the scenarios indicate that going into the latter half of the 21st century, approximately one-and-a-half billion additional people will experience at least moderately stressed water conditions worldwide, and of that, one billion will be at least will be living within regions under heavily stressed water conditions,” says Schlosser.

In another invited talk, “The Impact of Water Scarcity on Food, Bioenergy and Deforestation,” Joint Program Principal Research Scientist Niven Winchester will show that including an explicit representation of irrigated land and water scarcity in an economy-wide model has little impact on food prices, bioenergy production and deforestation. The results are similar for global carbon policy and no-policy scenarios.  

CGCS and Joint Program postdoctoral associate Liyi Xu will present a poster, “Multi-Land Surface Models Sensitivity Study on Ecosystem Responses to Enhanced and Extended Drought Conditions,” that uses four land-surface models to investigate the sensitivity of ecosystem hydrological responses to droughts of different time scales and magnitudes. The results explore and assess the models' response and recovery to prolonged drought conditions and the extent to which "warm" drought conditions impose an additional stress. 

Air pollution

CGCS and Joint Program Affiliate Noelle Selin, an associate professor in the Institute for Data, Systems and Society (IDSS) and Department of Earth, Atmospheric and Planetary Sciences (EAPS), will present an invited talkComparing climate policy co-benefits in the United States and China.” Using modeling approaches that integrate atmospheric chemistry, economic analysis and health impacts calculations, Selin will evaluate the co-benefits of greenhouse gas (GHG) reduction policies for each of the two leading GHG emitters at national and regional scales. 

Three graduate students in Selin’s group will also present posters on climate-related air pollution. 

IDSS PhD candidate/Joint Program research assistant Amanda Giang’s poster, “Implications of climate variability for monitoring the effectiveness of global mercury policy,” examines how natural variability in climate contributes to uncertainty in how effective policy may be in reducing the amount of mercury entering ecosystems through wet deposition—and how an improved understanding of climate variability can inform the Conference of Parties on monitoring strategy and policy ambition. EAPS PhD candidate/Joint Program research assistant Mingwei Li’s poster, Effects of Climate Variability on Transpacific Transport of Ozone, studies the impact of climate variability on trans-Pacific ozone (which may partially offset the benefits from U.S. domestic emission control policies) in the spring (its strongest season) using a global chemical transport model.  

Finally, EAPS graduate student Tao Feng’s poster, “Influence of Air Pollutant Emission Controls on the ‘Climate Penalty’ in the United States,” estimates the U.S. climate penalty (increased pollutant concentrations due to climate change) for ozone and fine particles as a function of four different local (U.S.) non-GHG emissions scenarios. “Consistent with previous work, we find a ‘climate penalty’ for O3 and PM2.5 in the U.S. by 2100 across all four scenarios,” says Feng. “We also find a climate-related decrease in the concentration of nitrous oxide and nitrate, and an increase in black carbon, organic carbon and sulfate.”

Climate Change

In his talk “Climate Response Functions for the Arctic Ocean,” CGCS and Joint Program Research Scientist Jeffery Scott compares “Climate Response Functions,” which he defines as “the transient response of key observable indicators such as sea ice, freshwater content, fluxes across important Arctic gateways, among other metrics to abrupt ‘step’ changes in forcing fields (i.e. winds, freshwater and heat sources),” across several Arctic models. 

CGCS and Joint Program Research Scientist Xiang Gao’s talk, “Heavy Precipitation in Regional Climate Models: Does it Pay to Play Analogue?,” investigates whether the detection of heavy precipitation events can be improved by combining (1) a method that uses resolved large-scale atmospheric conditions in General Circulation Models (GCMs) to detect the occurrence of heavy precipitation events with (2) higher-resolution regional climate model simulations from the North American Regional Climate Change Assessment Program (NARCCAP). 

“The results will assess advantages between computationally expensive high-resolution regional models versus extensively available low-resolution GCMs in assessing heavy precipitation frequency based on resolved atmospheric patterns,” says Gao.

in his talk, “Contributions of Uncertainty in Droplet Nucleation to the Indirect Effect in Global Models,” CGCS and Joint Program postdoctoral associate Daniel Rothenberg will discuss his approach to reduce uncertainty in the aerosol indirect effect (AIE)—how much anthropogenic aerosols increase the reflectivity of clouds, thereby reducing the amount of solar radiation that reaches the Earth’s surface and impacting its climate. Rothenberg’s research suggests that “targeted observations of cloud microphysical properties across different cloud regimes and their sensitivity to aerosol influences could help provide firm constraints and targets for models.”

CGCS and Joint Program Research Scientist Andrei Sokolov’s poster, “Probabilistic Estimates of Climate Impacts of the Paris Agreement,” presents probabilistic estimates of possible impacts of COP21 greenhouse gas-reduction policies (extending initial pledges to 2100) using the MIT Integrated Global System Modeling (IGSM) framework. 

“Our analysis shows that, for the climate parameters corresponding to the median strength of the climate system response to anthropogenic forcing, the Paris Agreement can reduce the global mean surface air temperature (SAT) in 2100 between 0.5 and 0.8oC relative to ‘no climate policy’ case,” says Sokolov. The poster contrasts COP21 results with an emissions scenario consistent with 2oC stabilization.” 

CGCS and Joint Program Principal Research Scientist Erwan Monier’s poster, “Integrated modeling of land-use change: the role of coupling, interactions and feedbacks between the human and Earth systems,” examines which coupled elements, interactions and feedbacks—among climate, energy, water and land—are important for modeling land-use change, both at the global and regional level. The poster highlights the current lack of clarity in how various components of human and Earth systems are coupled in Integrated Assessment Models, and the need for a common language to address it.

Finally, EAPS graduate student/Joint Program affiliate Charles Gertler will present a poster coauthored by Monier and CGCS Director and Joint Program Co-Director Ronald Prinn, “The Role of Arctic Sea Ice in Last Millennium Climate Variability: Model-Proxy Comparisons Using Ensemble Members and Novel Model Experiments.” Seeking to characterize the effects of natural and anthropogenic climate forcing on sea ice and the related changes in large-scale atmospheric circulation, the poster shows how a combination of instrumental record, paleoclimate reconstructions and general circulation models can be used to recreate the extent of sea ice and corresponding states of the atmosphere and ocean.


Prinn is also the coauthor of four talks and posters related to the Advanced Global Atmospheric Gases Experiment (AGAGE), which has been measuring the composition of the global atmosphere continuously since 1978. 

These include an invited talk by EAPS postdoctoral associate Alicia Gressent (“Optimal estimation of Sulfuryl Fluoride emissions on regional and global scales using advanced 3D inverse modeling and AGAGE observations”), a talk by EAPS graduate student Michael McClellan (“Source-Specific Nitrous Oxide Emissions in Ireland and UK from New Isotopically Resolved Measurements and Models”) and a poster by EAPS PhD candidate Jimmy Gasore (“First Continuous High Frequency in Situ Measurements of CO2 and CH4 in Rwanda Using Cavity Ring-Down Spectroscopy, and Preliminary Results of Regional Emission Estimation“). 

Prinn will refer to AGAGE and the Joint Program as examples in an additional talk, “Valuing and Maintaining Independent Research with Private Sector Funding.”