HR: 13:40h
AN: B33F-01    [Abstracts]
TI: Is There a Human Effect on the Climate System?
AU: * Pielke, R A
EM: pielke@atmos.colostate.edu
AF: Colorado State University, Atmospheric Science Department 1371 Campus Delivery, Fort Collins, CO 80523 United States
AU: Hiemstra, C A
EM: hiemstra@atmos.colostate.edu
AF: Colorado State University, Atmospheric Science Department 1371 Campus Delivery, Fort Collins, CO 80523 United States
AU: Lin, J C
EM: jcl@atmos.colostate.edu
AF: Colorado State University, Atmospheric Science Department 1371 Campus Delivery, Fort Collins, CO 80523 United States
AU: Matsui, T
EM: matsuit@atmos.colostate.edu
AF: Colorado State University, Atmospheric Science Department 1371 Campus Delivery, Fort Collins, CO 80523 United States
AU: Adegoke, J
EM: adegokej@umkc.edu
AF: University of Missouri-Kansas City, Department of Geosciences 420K Flarsheim Hall, Kansas City, MO 64110 United States
AU: Nair, U
EM: nair@nsstc.uah.edu
AF: Global Hydrology and Climate Center, University of Alabama, Huntsville, Huntsville, AL 35805 United States
AU: Niyogi, D
EM: dniyogi@purdue.edu
AF: Purdue University, Department of Agronomy Lilly Hall of Life Sciences 915 W. State Street, West Lafayette, IN 47907 United States
AB: As discussed in depth in the NRC (2005) report, human effects on the climate system are diverse and include, in addition to the radiative effect of greenhouse gases such as carbon dioxide and methane, influences from aerosols, land-use/land-cover change, and the biogeochemical effects of enhanced CO₂ and nitrogen deposition. As concluded in the Rial et al. (2004) multi-authored paper ``Nonlinearities, Feedbacks, and Critical Thresholds within the Earth's Climate System" (http://blue.atmos.colostate.edu/publications/pdf/R-260.pdf): ``The Earth's climate system is highly nonlinear: inputs and outputs are not proportional, change is often episodic and abrupt, rather than slow and gradual, and multiple equilbria are the norm...... It is imperative that the Earth's climate system research community embrace this nonlinear paradigm if we are to move forward in the assessment of the human influence on climate." The IPCC studies have convincingly shown that there are long-term effects on the climate system due to the human input of carbon dioxide into the atmosphere. However, the issuance of carbon permits alone will not satisfactorily address the more complex (and realistic) questions as to how human activity is altering the climate system. Indeed, it should be no surprise that when we change the composition of the Earth's atmosphere, we alter its energy budget, and thus other aspects of the climate system. The IPCC conclusions should be interpreted, however, as process studies. In that context they tell us that elevated atmospheric concentrations of well-mixed greenhouse gases due to human activity do affect our climate system. However, carbon dioxide is just one human climate forcing. It is not the only first-order climate forcing, as clearly articulated in the NRC (2005) report. The term ``global warming" has inaccurately been used as a synonym for climate change. ``Global warming", however, is a grossly inadequate term to characterize the actual human effect on the climate system. Such a narrow focus, and use of the term ``global warming" fails to recognize that other first-order climate forcings exist, in addition to the radiative forcing of carbon dioxide. These climate forcings include the effects of aerosols and land-use/land-cover change. Our talk will present recent research into the role of the diverse climate forcings, as integral components of the Earth's climate system.
DE: 0400 BIOGEOSCIENCES
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0466 Modeling
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1632 Land cover change
SC: Biogeosciences [B]
MN: Fall Meeting 2005