Tricks up nature's sleeve
All of the following have an element of

speed - the thing which poses the main

threat in terms of global climate change

The climate system is sufficiently complex, climatic models sufficiently simple and our understanding of the phenomenon of global climatic change sufficiently rudimentary that surprises of some sort can certainly be expected...
  • A sudden reorganisation of the global oceanic circulation. Commonly found in models of climatic response to GHG emissions. It accords with basic ideas (basic science and common sense)

  • An abrupt disappearance of permanent sea ice in the Arctic. This can come about because of a breakdown in the underlying salinity structure. This structure currently divides the surface water from the warmer water at the lower depths, which originates in the North Atlantic. See also:

  • A rapid melting of the Arctic ice cap. Artic temperatures are much more delicately poised around freezing, so a small rise would result in large-scale ice melt. Such a rise would not have the same effect in Antarctica, where temperatures are way below freezing point. This would dramatically affect global oceanic and atmospheric ciculation.

  • A sudden change in climatic sensitivity causing rapid climatic change. Changes in water vapour containment in the atmosphere could change this. This is realistic and reasonable as a hypothesis.

  • Abrupt changes in precipitation patterns. This has happened often enough in the past and could well be triggered by global scale climatic change.

  • An abrupt die-back of forests, as climatic zones shift at a rate faster than that at which forest zones can migrate. This could lead to critical thresholds being passed. The significance of this in the light of forest sink considerations is considerable.
It follows from this that we need a precautionary approach in response to the prospect of rapid and essentially irreversible climatic change.

See also un climate change guide facts & figures