date: Tue, 30 Oct 2007 13:23:19 +0000 from: Tim Osborn subject: recently submitted paper abstract to: cru.all@uea Hi everyone, we decided a while ago that when papers are submitted we should email around a copy of the abstract to everyone in CRU so we can keep up with forthcoming work and not be taken by surprise when some relevant work gets published. I keep forgetting to do this (as do others)! But, in case anyone out there has an interest in polar bears, this has just been submitted.... O'Neill SJ, Osborn TJ, Hulme M, Lorenzoni I, Watkinson AR (2007) Expert assessment of the uncertainties of polar bear population dynamics under climate change. Submitted to Journal of Applied Ecology. Abstract Polar bear population dynamics under climate change has become a controversial topic. A survey of expert opinion (the first ever undertaken for a particular species) based on modelled sea-ice data was performed in order to quantify the trends and variance surrounding possible impacts of climate change on polar bear populations. 1. Polar bears Ursus maritimus have become an iconic species in the communication of climate change, with media coverage implying a rapid population decline. This contrasts with scientific research, which indicates that most populations are currently stable or growing. Negative impacts of climatic warming on polar bears have been suggested, but cannot be quantified as no models yet exist to analyse the relationship between polar bear population dynamics and climate change. 2. Ten polar bear experts participated in an expert opinion survey, quantifying the trends and variance surrounding possible impacts of climate change on polar bear populations. The experts were provided with maps and time series of sea-ice extent and duration to 2050, simulated under mid-range emissions scenario SRES A1B. Expert responses for future polar bear habitat range and population size across the Arctic, and for population size in five regions, were obtained. Experts were asked to define 'best conservation practice', and to re-evaluate the total Arctic population projection if this best practice was implemented. 3. Most experts project a substantial decline in polar bear range and population across the Arctic, and in population across each region. Expert best estimates for total Arctic polar bear population size lie from no change to a 70% decrease relative to today; with half the experts projecting at least a 30% decrease. The median best estimates show the Barents Sea, Hudson Bay and the Chukchi Sea populations experiencing the greatest population decline under this scenario. There is much uncertainty both within and between expert responses, especially in little-researched regions such as the Chukchi Sea. 4. Synthesis and Applications. The responses of experts suggest polar bear populations will undergo significant declines by 2050, even implementing best management practices, under the scenario of climatic warming outlined here. In order to minimise population decline many experts believed that a precautionary approach to hunting is needed. However, unless conservation management of polar bears is teamed with global mitigation efforts there is little prospect of preventing significant population declines. Dr Timothy J Osborn, Academic Fellow Climatic Research Unit School of Environmental Sciences University of East Anglia Norwich NR4 7TJ, UK e-mail: t.osborn@uea.ac.uk phone: +44 1603 592089 fax: +44 1603 507784 web: http://www.cru.uea.ac.uk/~timo/ sunclock: http://www.cru.uea.ac.uk/~timo/sunclock.htm