Climate Change and a Global City: An Assessment of the Metropolitan East Coast Region

Fig. 1: Conceptual model for the MEC assessment.

Drs. Cynthia Rosenzweig, Vivien Gornitz, Ellen Hartig, Richard Goldberg, and Reggie Blake of Goddard Institute for Space Studies' climate impacts group are working with researchers from other institutions in the greater New York City area on "Climate Change and a Global City: An Assessment of the Metropolitan East Coast Region." The Metro East Coast (MEC) Regional Assessment contributes to The U.S. National Assessment: The Potential Consequences of Climate Variability and Change, a federally mandated investigation of impacts of climate variability and change at the local level.

MEC researchers collaborate with local stakeholders to explore the effects of climate on the New York metropolitan region. Stakeholders are institutions whose activities are and will be impacted by present and future climate variability and change and thus, have a stake in being involved in research of potential impacts. The project applies climate change scenarios from global climate models to regional climate impacts in seven sectors: coasts, infrastructure, wetlands, water supply, public health, energy demand, and institutional decision-making. Key overlapping impacts are defined through integration across sectors.

Climate change scenarios provide a range of plausible future climates and serve as the basis for the assessment of impacts in the MEC study. Current climate trends are projected into the

Fig. 2: (a) Average observed temperature for the past century. (b) Average observed precipitation for the past century.

future to provide one future climate scenario. Figures 2a and 2b show the observed temperature and precipitation data from the past century. Global climate models (GCMs) are mathematical computer models that simulate future precipitation and temperature changes in response to projected increases in CO₂ and other greenhouse gases.

The MEC Assessment bases its impacts research on a series of four GCM simulations. Two of the modeled scenarios account for the effects of greenhouse gases on the climate: HCGG (Hadley Centre Greenhouse Gas) and CCGG (Canadian Centre Greenhouse Gas). The other two model-driven scenarios consider both the effects of greenhouse gases and of sulfate aerosols on the climate system: HCGS (Hadley Centre Greenhouse and Sulfate) and CCGS (Canadian Centre Greenhouse and Sulfate). While greenhouse gases produce a warming in the atmosphere because they hold in solar radiation, sulfate aerosols tend to have a cooling effect, because they reflect solar radiation. Figures 3a and 3b show the projected temperature and precipitation changes for the scenarios.

We have chosen three future time slices, the 2020s, the 2050s, and the 2080s, for consideration of future impacts. The sector researchers examine relationships between current climate variability and impacts and extrapolate potential climate impacts using climate change scenarios.

The MEC Regional Assessment focuses on issues of climate change in an urban area. Our research and

Fig. 3: (a) Projected annual temperature for the Metro East Coast Region. (b) Projected average annual precipitation in the Metro East Coast Region

findings are especially important as the trend of urbanization continues. Human populations are increasingly concentrated in cities, and the number and size of cites are growing. It is estimated that half of the world's population lives in cities or on the coasts. The New York metropolitan region exemplifies both of these conditions.

As seen in the remote sensing image in Figure 4, New York City's land-use patterns dictate the amount of vegetative cover it has, and the subsequent heat indices of various areas. The city's interactions with climate, both as a heat island and as it is affected by the weather, is inextricably bound with its land-use pattern. This type of data allows us to examine climate impact relationships both spatially and temporally.

Research foci include:

• Coasts and Wetlands: Rates and effects of sea level rise and storm surges on the coastal regions of New York metropolitan region, including wetland loss.
• Infrastructure: Risk to the infrastructure in the Metropolitan East Coast region. We extrapolate storm surge risks into the future while accounting for effects of climate change. At the same time we try to introduce probabilistic concepts into the assessment of the storm surge risk.
• Water Supply: Potential impacts of climate change on demand and supply of regional water supply systems, suggesting types of adaptive measures that might be undertaken.
• Health: Human health concerns including heat- related mortality and morbidity and asthma, as they relate to climactic factors.
• Energy: Effects of higher temperatures on energy demand, determining changes in peak summer electricity loads as well as overall energy demand. The focus is on indoor climate control in residential and commercial buildings.

Fig. 4: Remote sensing image depicting combined vegetation and surface temperature of New York City.

• Decision-Making: Specific organizational functions and programs that are relevant to preparation for and/or response to the potential consequences of climate impacts. This assessment reveals various levels of capacity in organizations in each sector as well as various impediments to incorporating climate change planning into decision-making, while revealing the many links, hierarchies, and dependencies between and among organizations, which significantly affect decision-making on issues relevant to climate change and its potential impacts.

The MEC project contributes new research to existing knowledge of climate responses in the New York metropolitan region. In the research and assessment process, the participants in the project focus on the challenges and opportunities posed by climate variability and change. Through outreach to and the involvement of the regional stakeholder community, the MEC Assessment promotes climate awareness in our global city.

Further Information

Please visit the Metropolitan East Coast Assessment and the The U.S. National Assessment websites.

Contacts

For further information about the Metropolitan East Coast Regional Assessment project, please contact Dr. Cynthia Rosenzweig