Background
Climate alarmists typically claim that CO2-induced global warming will be so fast and furious that many species of plants and animals will not be able to migrate towards cooler regions of the planet (poleward in latitude and/or upward in elevation) rapidly enough to avoid extinction.

What was done
In a study that addresses this claim, the author categorized birds of Finland as either northerly (34 species) or southerly (116 species) and quantified changes in their range margins and distributions from two atlases of breeding birds, one covering the period 1974-79 and one covering the period 1986-89, in an attempt to determine how the two groups of species responded to what he calls "the period of the earth's most rapid climate warming in the last 10,000 years which started in 1976 (McCarthy et al., 2001)."

What was learned
It was determined that the southerly group of bird species experienced a mean poleward advancement of their northern range boundaries of 18.8 km over the 12-year period of supposedly unprecedented warming.  However, the southern range boundaries of the northerly group of bird species were essentially unmoved by the skyrocketing temperature; and this result, in the words of the author, "did not change when raptors and threatened species were omitted from the analyses."

What it means
Noting that similar results have been obtained for birds in the United Kimgdom (Thomas and Lennon, 1999) and other species (primarily butterflies) elsewhere (Parmesan, 1996; Parmesan et al., 1999), Brommer concludes that "in general, for northern hemisphere species, southerly range margins of species are less responsive to climate change than the northerly margins."  As a result, it can be appreciated that the ranges of such species in a warming world will actually increase in size, as their northern range boundaries expand poleward and upward while their southern range boundaries remain largely unaltered, which should render them less subject to extinction than they are currently.

For more on this subject, see our major report The Specter of Species Extinction: Will Global Warming Decimate Earth's Biosphere?

References
McCarthy, J.J., Canziani, O.F., Leary, N.A., Dokken, D.J. and White, K.S., Eds.  2001.  Climate Change 2001: Impacts, Adaptation, and Vulnerability.  Cambridge University Press, Cambridge, UK.

Parmesan, C.  1996.  Climate and species' range.  Nature 382: 765-766.

Parmesan, C., Ryrholm, N., Stefanescu, C., Hill, J.K., Thomas, C.D., Descimon, H., Huntley, B., Kaila, L., Kullberg, J., Tammaru, T., Tennent, W.J., Thomas, J.A. and Warren, M.  1999.  Poleward shifts in geographical ranges of butterfly species associated with regional warming.  Nature 399: 579-583.

Thomas, C.D. and Lennon, J.J.  1999.  Birds extend their ranges northwards.  Nature 399: 213.