Regional Climate Assessments

Global mean-annual temperatures this century are projected to rise up to 4°C if greenhouse gas emissions continue unabated. Even if COconcentrations do not continue to rise, there may be as much as 2°C of warming caused by interaction between the atmosphere and the ocean’s large thermal inertia. It is inevitable that temperature change associated with rising CO2 levels will impact hydrologic cycles and consequences of these changes would likely have immediate effects on weather and global patterns of precipitation. Sea-level rise, weather extremes, and sea-ice evolution have direct cultural, demographic, and public health impacts that are presently unfolding. Constraining the extent of future warming requires an improved understanding of factors that amplify or dampen radiative effects of greenhouse gas concentrations, as well as other climate forcers and their future evolution. While global simulations broadly agree across different institutional climates model, regional simulations of future climates differ substantially. Understanding the disparities in regional models is key to future forecasting and planning across all aspects of society, including human health.

The Northeast Region Climate Assessment assembles a consortium of universities to develop a framework of high-resolution predictive models for the changing climate, economic activity, public health, land use and energy demands of New England and adjoining regions (such as natural gas production areas in Pennsylvania and high-value property of coastal New Jersey). The models are intended to provide the kind of detailed predictions, as well as associated uncertainties or risks needed to design effective policies, infrastructure plans and investment strategies for a full range of human enterprise over the next twenty years and beyond. Outputs will include temperature, soil moisture, storm frequency and intensity, sea level and storm surges, ground water levels and saline incursion, vegetation and agriculture, as well as animal and insect ranges, including infectious disease vectors such as deer ticks and the newly arrived Asian tiger mosquito. Project partners include  the University of New Hampshire, the University of Massachusetts-Amherst, and MIT,

The first project goal involves utilizing a global climate model, the Community Earth System Model (CESM at 1.25º resolution), and the regional Weather and Research Forecasting model to produce high-resolution climate results as input for a Lyme disease model. Outputs will include likelihood maps of changes in disease ranges and vector distribution for the Northeast US for the coming century. In addition, YCEI will work to expand research coalitions with other universities and groups and apply climate model results to determine changes in the range of other infectious disease such as mosquito-borne viruses, changes in ecology, hurricane frequency and intensity, agricultural stress, changes in forest compositions, impacts of coastal inundation and sea-level rise. The program’s ultimate goal is to assess the range of climate impacts resulting in mitigation and adaptive strategies for the Northeast, including New Haven and Yale University, for the coming century.  An overlay of existing county-level data on opinions related to climate change provided by the Yale Project for Climate Change Communication will provide a unique dimension for policy creation and interpretation of results.

The project is divided into two phases. Phase I is projected to last three years and entails stakeholder outreach, policy workshops and symposia, gathering of data for model inputs, and the initial design, building and calibration of the first set of models, including an “alpha version” of the high-resolution land-use, economic and climate models.   Phase II involves refinement, testing and optimization of the high-resolution models starting in the project’s fourth year and continuing for three years. YCEI will publish data and conclusions from Phase I at the end of the project’s fourth year. A final report, including a public-domain version of the full model, will be available within one year after the end of Phase II.

Phase I, now underway involves using existing tools such as NCAR’s Community Earth System Model to downscale the output of coarse global and regional climate models that are already available at scales of 50 km or more. These results will be used to build an initial regional climate assessment for the Northeast for the next fifty years. This coarse-model assessment will serve as the baseline for a series of high-resolution model simulations. The target resolution for the final models is a 4-by-4 km grid. Development of realistic model results at such scales constitutes the main research component of the project and will require informed use of climate, environmental, economic and public health modeling tools. Testing and projection of various scenarios will be conducted in collaboration with project partners and stakeholders, that include representatives from key sectors including agriculture, manufacturing, transportation, property development and insurance industries.

Armed with predictive tools that can better estimate risks to food production, the economy and public health, YCEI hopes to provide decision-makers with a planning tool to help ease the collective transformation that has the unique capacity to provide updated results in response to the dynamic nature of CO2 emissions and improved understanding of climate sensitivity.

Plans for an East Africa and Middle East Climate Assessment that essentially replicates the methodology proposed for the Northeast United States were requested by the Republic in May of 2015.  The proposed study area includes Somalia, Djibouti, Ethiopia, Eritrea, Egypt, Southern Turkey, the Arabian Peninsula, and the remainder of the Middle East. Phase I for this project would involve settling basic questions of regional meteorology relating to the influences of the West Africa and Asian monsoons. A write-up on the Yale-led Taskforce’s visit to the region is here.