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Climate has changed
CLIMATE has changed significantly
in the PAST
and has definitely changed in
RECENT DECADES
Vostok ice core record (Temp, CH4, CO2)
Adapted from: Petit et al., NATURE, 399: 429-436 (1999)
(For this diagram, please see:
Mann, Michael E. “The Value of Multiple Proxies.” Science 297 (30 August 2002): 1481-2. NH temperature histories.
http://www.sciencemag.org/cgi/reprint/297/5586/1481.pdf)
(For this diagram, please see:
Intergovernmental Panel on Climate Change. “Summary for
Policymakers: A Report of Working Group I of the
Intergovernmental Panel on Climate Change.” Figure 1(a), p. 3.
“Climate Change 2001: Synthesis Report.”
http://www.ipcc.ch/pub/un/syreng/wg1spm.pdf)
WHAT IS THE NATURE
OF THE SYSTEM THAT
DETERMINES CLIMATE?
The Earth is a Dynamic System
…That Changes on all Time Scales
Courtesy of the Intergovernmental Panel on Climate Change. Used with permission.
ENERGY BALANCE IN THE CLIMATE SYSTEM
WHAT ARE THE VERTICAL FLOWS OF ENERGY
THAT DETERMINE GLOBAL TEMPERATURES?
THE FUNDAMENTAL UNITS WE WILL USE TO MEASURE FLOWS ARE WATTS/(METER)2
IPCC_TAR_Working Group 1_1.2. Courtesy of the Intergovernmental Panel on Climate Change. Used with permission.
HUMAN & OTHER INFLUENCES ON CLIMATE
HOW IS THE COMPOSITION OF THE
ATMOSPHERE CHANGING?
HOW HAVE THE ENERGY FLOWS CHANGED
SINCE PRE-INDUSTRIAL TIMES?
RADIATIVE FORCING (watt/m2) IS THE CHANGE IN THE VERTICAL ENERGY FLOW (at the tropopause) INDUCED BY CHANGES IN
GREENHOUSE GASES, AEROSOLS, & OTHER CLIMATE FORCING
PROCESSES
i .FIGURE 2: Long records of past changes in atmospheric composition provide the context for the influence of anthropogen c emissions
Courtesy of the Intergovernmental Panel on Climate Change. Used with permission.
AEROSOL EFFECTS
sunlight
smaller cloud droplets which (1) increases reflection, and (2) suppresses rainfall
(C) Semi-direct effect: absorbing aerosols heat air and cool surface suppressing convection and condensation
(A) Direct Effect: aerosols reflect or absorb
(B) Indirect Effects: aerosols create more and
MASSAC
HUSETTS
INSTITUTE OF TECH
NOLO
GY
ALE/GAGE/AGAGE CCl3F monthly mean mole fractions and standard deviations.
EFFECTS OF MONTREAL PROTOCOL
Climate Forcings 1850 to 2000
F ( W
/ m
2 )
Courtesy of the Intergovernmental Panel on Climate Change. Used with permission.
Hansen, J., R. Ruedy, M. Sato, and R. Reynolds. "Global surface air temperature in 1995: Return to pre-Pinatubo level." Geophys. Res. Lett. 23, no. 13(1996): 1665-1668. Copyright [1996] American Geophysical Union. Reproduced/modified by permission of American Geophysical Union.
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