Biological and Environmental Research - Earth and Environmental System Sciences
Earth and Environmental System Modeling

Sensitivity of Regional Climate to Global Temperature and Forcing

TitleSensitivity of Regional Climate to Global Temperature and Forcing
Publication TypeJournal Article
Year of Publication2015
AuthorsTebaldi, Claudia, O'Neill Brian, and Lamarque Jean-Francois
JournalEnvironmental Research Letters
Volume10
Number7
Pages074001
Abstract / Summary

ding of the consequences exceeding them, even by small amounts, and the effective design of sets of scenarios requires the knowledge of how different emissions, concentrations, or forcing need to be in order to produce substantial differences in climate outcomes. Using an extensive database of climate model simulations, we quantify how differences in global average quantities relate to differences in both the spatial extent and magnitude of climate outcomes at regional (250–1250 km) scales. We show that differences of about 0.3 °C in global average temperature are required to generate statistically significant changes in regional annual average temperature over more than half of the Earth's land surface. A global difference of 0.8 °C is necessary to produce regional warming over half the land surface that is not only significant but reaches at least 1 °C. As much as 2.5 to 3 °C is required for a statistically significant change in regional annual average precipitation that is equally pervasive. Global average temperature change provides a better metric than radiative forcing for indicating differences in regional climate outcomes due to the path dependency of the effects of radiative forcing. For example, a difference in radiative forcing of 0.5 W m−2 can produce statistically significant differences in regional temperature over an area that ranges between 30% and 85% of the land surface, depending on the forcing pathway.

URLhttps://doi.org/10.1088/1748-9326/10/7/074001
DOI10.1088/1748-9326/10/7/074001
Journal: Environmental Research Letters
Year of Publication: 2015
Volume: 10
Number: 7
Pages: 074001
Publication Date: 07/2015

ding of the consequences exceeding them, even by small amounts, and the effective design of sets of scenarios requires the knowledge of how different emissions, concentrations, or forcing need to be in order to produce substantial differences in climate outcomes. Using an extensive database of climate model simulations, we quantify how differences in global average quantities relate to differences in both the spatial extent and magnitude of climate outcomes at regional (250–1250 km) scales. We show that differences of about 0.3 °C in global average temperature are required to generate statistically significant changes in regional annual average temperature over more than half of the Earth's land surface. A global difference of 0.8 °C is necessary to produce regional warming over half the land surface that is not only significant but reaches at least 1 °C. As much as 2.5 to 3 °C is required for a statistically significant change in regional annual average precipitation that is equally pervasive. Global average temperature change provides a better metric than radiative forcing for indicating differences in regional climate outcomes due to the path dependency of the effects of radiative forcing. For example, a difference in radiative forcing of 0.5 W m−2 can produce statistically significant differences in regional temperature over an area that ranges between 30% and 85% of the land surface, depending on the forcing pathway.

DOI: 10.1088/1748-9326/10/7/074001
Citation:
Tebaldi, C, B O'Neill, and J Lamarque.  2015.  "Sensitivity of Regional Climate to Global Temperature and Forcing."  Environmental Research Letters 10(7): 074001.  https://doi.org/10.1088/1748-9326/10/7/074001.