Climate change over the last 2000 years -- what do we (really) know?

08/04/05

Panel discussion at PAGES Open Science Meeting, 10-12 August, Beijing

In a "warts and all" panel discussion, a group of influential scientists will battle out the myths and realities of what we really know about temperature records since the time of Christ.

The so-called "hockey stick" curve by Michael Mann and others shows global temperature over the past millennium reconstructed from a variety of "proxy" records such as tree rings, ice core samples and corals. The curve underpinned the IPCC's (Intergovernmental Panel on Climate Change) 2001 Scientific Assessment that formed the basis of the Kyoto Protocol.

Now the curve is the subject of considerable debate and controversy and has been scrutinised by scientists, politicians and other interested groups.

Sceptics of human-induced climate change argue that such reconstructions and models can only roughly reproduce the temperature amplitudes and trends of the last two millennia, and thus cannot be relied on for predictions of future climate change.

"This round table will provide an overview on the current state of the discussion in the scientific community and will attempt to assess whether the statements in the IPCC 2001 Scientific Assessment should be modified or not," says Heinz Wanner, head of the Swiss Climate Research Center and the moderator of the discussion.

"It will also provide an important basis for the ongoing discussions on the future of the Kyoto Protocol, especially regarding the involvement of countries such as the United States, Australia and India," he said.

The Panel:
Mike Mann (Pennsylvania State University, USA) can be called the father of the "hockey stick". His reconstructions and complementary modelling of the Earth's temperature evolution over the last millennium provided the context for the view that the recent decades' climate change was exceptional and man-made.

Gavin Schmidt (NASA Goddard Institute for Space Studies, New York) is a leading modeller of modern as well as past climate change. He is also very active in disseminating the scientific climate change debate to the public, e.g. via the realclimate.org web blog.

Dmitry Sonechkin (HydroMeteorological Research Centre of Russia, Moscow) is a mathematical climatologist and co-author of the Moberg, et al. 2005 Nature paper that challenged Mann et al.'s low amplitude of climate variability in the pre-industrial millennia.

The moderator:
Heinz Wanner (University of Bern and Swiss Climate Research Center) is a paleo-meteorologist who uses climatic evidence for the last centuries from historical documents, natural archives, and model simulations to understand the detailed functioning of climate dynamics on hemispheric to regional scales.

The discussion will also involve plenary participants, including many distinguished paleoscientists from all over the world.

Source: Eurekalert & others

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-- Robert Frost