Climate change impacts on extreme events in the United States: an uncertainty analysis

Abstract

In this study, we analyze changes in extreme temperature and precipitation over the US in a 60-member ensemble simulation of the 21st century with the Massachusetts Institute of Technology (MIT) Integrated Global System Model-Community Atmosphere Model (IGSM-CAM). Four values of climate sensitivity, three emissions scenarios and five initial conditions are considered. The results show a general intensification and an increase in the frequency of extreme hot temperatures and extreme precipitation events over most of the US. Extreme cold temperatures are projected to decrease in intensity and frequency, especially over the northern parts of the US. This study displays a wide range of future changes in extreme events in the US, even simulated by a single climate model. Results clearly show that the choice of policy is the largest source of uncertainty in the magnitude of the changes. The impact of the climate sensitivity is largest for the unconstrained emissions scenario and the implementation of a stabilization scenario drastically reduces the changes in extremes, even for the highest climate sensitivity considered. Finally, simulations with different initial conditions show conspicuously different patterns and magnitudes of changes in extreme events, underlining the role of natural variability in projections of changes in extreme events.

The role of natural variability in projections of climate change impacts on U.S. ozone pollution

“…Large year‐to‐year variations in the climate system resulting from natural variability can be associated with severe air pollution episodes and related health effects. For the climate ensemble used in this study, an important effect of natural variability in the projections of climate change impacts on meteorological extremes has been demonstrated [ Monier and Gao , ]. Given the interactions between meteorological variables and ground‐level O 3 noted above, natural variability can be expected to have a significant influence on projections of climate‐induced impacts on extreme air quality events.…”

A framework for modeling uncertainty in regional climate change

“…In addition, the two different methods have very different treatments of natural variability. The IGSM-CAM physically simulates changes in both mean climate and extreme events (Monier and Gao 2014), but relies on one particular model. The pattern scaling approach allows the spatial patterns of regional climate change of different climate models to be considered, but significantly underestimates yearto-year variability and cannot simulate extreme events or their potential changes under climate change.…”

Twenty-First-Century Changes in U.S. Regional Heavy Precipitation Frequency Based on Resolved Atmospheric Patterns

“…In particular, many studies have shown that extreme precipitation events are likely to respond substantially to anthropogenically enhanced greenhouse forcing with changes in their frequency and intensity (Wehner 2005;Kharin et al 2007;Sun et al 2007; Kao and Ganguly 2011;Min et al 2011;Pall et al 2011;Dominguez et al 2012;Kharin et al 2013;Sillmann et al 2013;Monier and Gao 2015). Such shifts could have dramatic ecological, economic, and sociological consequences (IPCC 2012).…”