27 J. Land Resources & Envtl. L. 101 (2007)
Abrupt Climate Changes: Past, Present and Future

handle is hein.journals/lrel27 and id is 109 raw text is: Abrupt Climate Changes:
Past, Present and Future
Lonnie G. Thompson*
The Earth's tropical regions are very important for understanding current and
past climate change as 50% of the Earth's surface lies between. 30'N and 30'S, and
it is these regions where most of the sun's energy that drives the climate system is
absorbed. The tropics and subtropics are also the most populated regions on the
planet. Paleoclimate records reveal that in the past, natural disruptions of the
climate system driven by such processes as large explosive volcanic eruptions' and
variations in the El Nifio-Southern Oscillation2 have affected the climate over
much of the planet.3 Changes in the vertical temperature profile in the tropics also
affect the climate on large-spatial scales. While land surface temperatures and sea
surface temperatures show great spatial variability, tropical temperatures are quite
uniform at mid-tropospheric elevations where most glaciers and ice caps exist.
Observational data before, during and after a major El Nifio event demonstrate that
within four months of its onset, the energy from the sea surface is distributed
throughout the tropical mid-troposphere.4 Thus, the observation that virtually all
tropical regions are retreating5 under the current climate regime strongly indicates
that a large-scale warming of the Earth system is currently underway.
* University Distinguished Professor, School of Earth Sciences, Senior Research
Scientist, Byrd Polar Research Center, The Ohio State University. The Journal of Land,
Resources & Environmental Law would also like to thank Dr. Ellen Mosely-Thompson
who significantly assisted the journal staff and editorial board in preparing this manuscript
while Dr. Lonnie Thompson was conducting field research in China.
See Alan Robock, Volcanic Eruptions and Climate, 38 REVIEWS OF GEOPHYSICS
191 (2000), available at http://www.agu.org/joumals/rg/rgOO02/1998RG000054/pdf/1998
2 Michael H. Glantz, Currents of Change: El Nino's Impact on Climate and Society
(Cambridge University Press 1996).
4 John C. H. Chiang & Adam H. Sobel, Tropical Tropospheric Temperature
Variations Caused by ENSO and Their Influence on the Remote Tropical Climate, 15 J. OF
CLIMATE 2616 (Sept. 15, 2002).
5 Mark B. Dyurgerov & Mark F. Meier, Twentieth Century Climate Change:
Evidence from Small Glaciers, 97 PROCEEDINGS NAT'L ACAD. SCIENCES 1406, 1409
(2000), available at http://www.pnas.org/cgi/reprint/97/4/1406; see also Lonnie G.
Thompson, Ellen Mosley-Thompson, Mary E. Davis, Ping-Nan Lin, K. Henderson & T.A.
Mashiotta, Tropical Glacier and Ice Core Evidence of Climate Change on Annual to
Millennial Time Scales, 59 CLIMATIC CHANGE 137 (2002), available at http://springerlink.
metapress.com/content/t2302533h2415v45/fulltext.pdf, Johannes H. Oerlemans, Extracting
a Climate Signal from169 Glacier Records, 308 SCIENCE 675, 675 (2005), available at

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