NASA's James Hansen claims that as temperatures around the world continue to rise, "polar species can be pushed off the planet, as they have no place else to go," and that life in alpine regions "is similarly in danger of being pushed off the planet," while England's Sir John Houghton declares that "we are in danger of losing thousands, if not millions, of species because of climate change."

These ominous words of warning, which portend significantly reduced species richness over much of the earth in future years -- if the planet continues to warm -- sound logical enough, but are they true?

[H/T to Marc]  The Intergovernmental Panel on Climate Change (IPCC) has stated that: Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations, mainly carbon dioxide.  This conclusion is based on output from global climate computer models known as General Circulation Models (GCM). 

David Douglass and John Christy, in a paper recently accepted for publication and already available on the internet, have come to a different conclusion.  By considering observed, as opposed to modelled, temperature changes and at different latitude bands they conclude that:

1. El Nino and La Nina effects in the tropics have a more significant affect on global temperature anomalies than carbon dioxide, in particular it was an El Nino event that drove the 1998 global temperature maximum.

Two new studies summarised in a news article in Science magazine point to wind-induced circulation changes in the ocean as the dominant cause of the recent ice losses through the glaciers draining both the Greenland and West Antarctic ice sheets, not ‘global warming.’

The two stuides referred to are:

‘Acceleration of Jakobshavn Isbræ triggered by warm subsurface ocean waters’ by Holland et al, published in Nature Geoscience.

The Abstract states:

Preliminary data from two Arctic cruises suggest that rising temperatures are already causing substantial amounts of methane to be released from beneath the ocean floor. But catastrophic gas leaks, like those believed to have occurred 55 million years ago, are unlikely, scientists say.

In the past few weeks, scientists aboard the British research ship James Clark Ross have discovered more than 250 plumes of methane bubbling up along the continental margin northwest of Svalbard. The findings add to a similar discovery by a Russian team in August, that reported elevated methane concentrations near the Lena River delta, as part of the International Siberian Shelf Study (ISSS).

The findings have provoked alarmist media reports predicting massive methane bursts that could accelerate global warming. Methane is a far more powerful greenhouse gas than carbon dioxide, although it is present in much lower concentrations in the atmosphere.