Description:

The seventh James R. Arnold Lecture will be given by Professor Lonnie Thompson, Distinguished University Professor, School of Earth Sciences, The Ohio State University. Professor Thompson is one of the world's foremost authorities on paleoclimatology and glaciology and will discuss the current and present danger posed by ongoing climate change as well as the human response to this danger.

EVENT: JAMES R. ARNOLD LECTURE
DATE: Friday, May 9, 2008
TIME: 5:00 - 7:00 PM

Refreshments Following

LOCATION:
Robinson Complex Auditorium
Graduate School of International Relations and Pacific Studies (IR/PS), UCSD

This lecture is free and open to the public. UCSD Parking permits are
required to park on campus, you can purchase a permit at one of the many
meters located at the parking structures. For more information and
directions please see the web page:

ABSTRACT: Glaciers are among the first responders to global warming,
serving both as indicators and drivers of climate change. Over the last 30
years the Ice Core Paleoclimate Research Group at The Ohio State University has been engaged in a program of systematic recovery of ice cores from high-elevation, low-latitude ice fields. The resulting climate records,
along with other proxy data, have produced three primary lines of evidence for past and present abrupt climate change. First, high-resolution time series of stable oxygen isotopes (temperature proxies) and net balance
(precipitation proxies) demonstrate that the current warming at high
elevations in the mid- to lower latitudes is unprecedented for at least the
last two millennia. Second, the continuing retreat of most mid to
low-latitude glaciers, many having persisted for thousands of years, signals
a recent and abrupt change in the Earth's climate system. Finally, there is
strong evidence within and around glaciers for a widespread and spatially
coherent abrupt event ~5.2 ka that marked the transition from early Holocene warmth to cooler conditions that occurred through much of the world and was coincident with structural changes in several civilizations. Together, these
three lines of evidence argue that the present warming and associated
glacier retreat are unprecedented in many areas for at least 5000 years.

Specific evidence of recent acceleration in the rates of ice loss of
glaciers will be presented. The current melting of these ice fields is
consistent with model predictions of both high latitude and vertical
amplification of temperatures in the tropics. The ongoing rapid,
global-scale retreat of mountain glaciers is not only contributing to global
sea level rise, but threatening fresh water supplies in many of the world’s
most populous regions. The current and present danger posed by ongoing
climate change and the human response will be discussed.

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