Frequently Asked Questions
What is the CIRA project?
The Climate Change Impacts and Risk Analysis (CIRA) project quantifies physical effects and economic damages to the United States under climate scenarios and levels of future warming. The goal of this work is to estimate climate change impacts in six broad U.S. sectors (health, infrastructure, electricity, water resources, agriculture, and ecosystems) and the reduced damages through greenhouse gas mitigation or adaptation. CIRA advances climate change damage estimation by bridging the gap between climate modeling and economic effects, presenting both physical and monetized damages.
Who is involved with CIRA?
CIRA is an EPA-led collaborative modeling effort that includes analytical teams within the federal government and scientists from academic institutions and consulting firms.
Are the CIRA reports scientific assessments, like the National Climate Assessment?
No, there is a difference. Climate change science assessments, such as those by the Intergovernmental Panel on Climate Change(IPCC) and U.S. Global Change Research Program (USGCRP), look across a larger body of scientific literature to develop consensus conclusions about the state of climate change science. The CIRA project, on the other hand, is more narrowly focused. It is designed to estimate physical and economic damages of climate change in the United States under different climate scenarios.
What is the precision of the results?
The CIRA reports provide insights into the direction and magnitude of climate change impacts and the benefits to the United States (avoided impacts) associated with greenhouse gas mitigation and adaptation actions. Importantly, the analyses estimate only some of the impacts of climate change and are, therefore, an incomplete picture of risks associated with climate change. The estimates in the reports should not be interpreted as definitive predictions of future impacts at a particular place and time. Instead, the intention is to produce estimates of future effects using the best available climate data and methods, which can be revisited over time as the science and modeling advance.
How are the CIRA reports peer reviewed?
CIRA reports build on multiple layers of independent peer review. First, the underlying datasets used throughout the project are established, peer-reviewed sets of information. Second, the methods and results of the underlying climate change impacts analyses are individually peer reviewed in scientific journals, which can be viewed here. Finally, the summary reports undergo external, independent peer review to ensure that the content accurately reflects the science, appropriately summarizes the results, and clearly communicates the methods and conclusions of the underlying papers.
How are the positive effects of climate change on the United States considered?
The CIRA analyses evaluate both negative and positive effects of climate change where the information and data are available. Overall, the negative effects of unmitigated climate change substantially outweigh the positive effects. For instance, the projected increase in deaths due to more frequent extremely hot days is estimated to be much larger than the projected decrease in deaths due to fewer extremely cold days.
Does CIRA consider adaptation to climate change?
Yes, the CIRA reports include analyses of the costs, benefits, and effectiveness of adaptation options for several sectors, including extreme temperature mortality, infrastructure (roads, bridges, and rail), winter recreation, and coastal property. This information not only allows for improved estimates of climate change impacts and economic costs, but also contributes to the knowledge base at national, regional, and local levels.
Does the CIRA project cover all climate change impacts?
No. The CIRA project describes certain important impacts of climate change, but many others are not included due to data availability and resource constraints. In addition, for some sectors, only part of the impact or damage is included in the estimate. For example, estimates for wildfires only include the costs associated with suppressing them and reducing fuels; other damages (e.g., property damages or loss of recreational space) are not included. The primary geographic focus of CIRA is on the contiguous United States. Most of the sectoral analyses exclude Hawai'i, Alaska, and the U.S. territories.
Does CIRA consider costs of reducing greenhouse gas emissions?
No. CIRA does not examine costs of mitigating greenhouse gases nor does it constitute a cost-benefit assessment of climate policy. The project only addresses analytical gaps focused on the impacts and damages to the United States. There are multiple policy approaches that could be undertaken to achieve any particular emissions reduction target or concentration pathway, but the CIRA reports do not discuss those approaches nor the costs of implementing any particular policy. There is a robust literature on climate mitigation costs, including Climate Change 2014: Mitigation of Climate Changeand the Energy Modeling Forum.