New Study Reveals Link Between 'Climate Footprints' and Mass Mammal Extinction

Wiley ^ | May 18, 2010 | Ben Norman

[SunkenCiv]

"Between 50,000 and 3,000 years before present (BP) 65% of mammal species weighing over 44kg went extinct, together with a lower proportion of small mammals," said lead author Dr David Nogues-Bravo working from the Center for Macroecology, Evolution and Climate in University of Copenhagen. "Why these species became extinct in such large numbers has been hotly debated for over a century."

During the last 50,000 years the global climate became colder and drier, reaching full glacial conditions 21,000 years before present time. Since then the climate has become warmer, and this changing climate created new opportunities for colonization of new regions by humans. While both of these global change actors played significant roles in species extinction this study reveals that changing climate was a significant force driving this mass extinction.

"Until now global evidence to support the climate change argument has been lacking, a large part of existing evidence was based on local or regional estimates between numbers of extinctions, dates of human arrivals and dates of climate change," said Dr Nogues-Bravo.

"Our approach is completely different. By dealing with the issue at a global scale we add a new dimension to the debate by showing that the impact of climate change was not equal across all regions, and we quantify this to reveal each continent's "footprint of climate change."

The study shows that climate change had a global influence over extinctions throughout the late quaternary, but the level of extinction seems to be related to each continent's footprint of climate change. When comparing continents it can then be seen that in Africa, where the climate changed to a relatively lesser extent there were fewer extinctions. However, in North America, more species suffered extinction, as reflected by a greater degree of climate change.

[gleeaikin]

I may be remembering this wrong, but I think BP which means Before Present, not British Petroleum in this context, counts back from 1950. After this date carbon 14 dating ran into difficulties because of Atomic Bomb effects and other nuclear radiation. So 100 years BP would be 1850 if I am correct.