Physical climate response to a reduction of anthropogenic climate forcing.
Arindam
Samanta, Boston University, arindam@bu.edu
(Presenting)
Bruce
T
Anderson, Boston University, brucea@bu.edu
Sangram
Ganguly, NASA AMES/BAERI, sangram.ganguly@gmail.com
Yuri
Knyazikhin, Boston University, jknjazi@bu.edu
Ramakrishna
R
Nemani, NASA AMES, nemani911@gmail.com
Ranga
B
Myneni, Boston University, ranga.myneni@gmail.com
Recent research indicates that the warming of the climate system resulting from increased greenhouse gas (GHG) emissions over the next century will persist for many centuries after the cessation of these emissions, due principally to the persistence of elevated atmospheric carbon dioxide (CO2) concentrations and their attendant radiative forcing. However, it is unknown whether the responses of other components of the climate system—including those related to Greenland and Antarctic ice cover, the Atlantic thermohaline circulation, the West African monsoon, and ecosystem and human welfare—would be reversed even if atmospheric CO2 concentrations were to recover to 1990 levels. Here, using a simple set of experiments employing a current-generation numerical climate model we examine the response of the physical climate system to decreasing carbon dioxide (CO2) concentrations following an initial increase. Results indicate that many characteristics of the climate system, including global temperatures, precipitation, soil moisture and sea ice, recover as CO2 concentrations decrease. However, other components of the Earth system may still exhibit non-linear hysteresis. In our experiments for instance, increases in stratospheric water vapor, which initially result from increased CO2 concentrations, remain present even as CO2 concentrations recover. These results suggest that identification of additional threshold behaviors in response to human-induced global climate change should focus on sub-components of the full Earth system, including cryosphere, biosphere, and chemistry.
Presentation Type: Poster
Poster Session: Carbon Cycle Science
NASA TE Funded Awards Represented:
NONE: Related Activity or Previously Funded TE Award