Having decided that short-term action is required, the next thing to ask ourselves is what price we are prepared to pay in environmental terms for adopting STEP. After all, fiddling with the biosphere has a chequered history (Cane toads, Nile perch, Strawberry Guava, Rhododendron etc. etc.). However careful we are, there inevitably will be some environmental cost!

The precise impact, of course, will vary with each scheme, but is there an overall set of guidelines which can be used? We already have a good idea of the effects of NOT adopting STEP measures. The IPCC tell us that:

"Expected directions of change relating to regional climate warming for physical systems include shrinkage of glaciers, decrease in snow cover, shortening of duration of lake and river ice cover, declines in sea-ice extent and thickness, lengthening of frost-free seasons, and intensification of the hydrological cycle. Expected directions of change relating to regional climate warming for biological systems include poleward and elevational shifts in distribution and earlier phenology (i.e., earlier breeding, emergence, flowering) in plant and animal species" . IPCC Report 2001, 19.2 Observations of Climatic change impacts

So what does this IPCC prediction really mean?
Temperature increases are likely to reach between 2 and 6 degrees by 2100. Among other things this will lead to a rise in sea levels due largely to melting icecaps and increased thermal expansion of the oceans. This will mean loss of coastal areas, increased coastal erosion and the threat of partial or virtually total inundation of many small island states and low lying areas. 2 billion people could be displaced.

Loss of habitat will lead to increased pressure on animal species and vegetation and hence extinction of numerous species. Perhaps, in subsequent years, we will see polar bears only as an animation on a cola advert as a bitter reminder of the losses induced by our own selfish activities.

In a warmer atmosphere, we can expect to see increased intensity of precipitation and a much higher risk of flooding, resulting in huge social and economic costs. Increased storm activity and intensity will ensue, extreme weather events will become more frequent and more deadly. Again the results of these weather systems are well known and increasingly familiar.

How many hurricanes, floods and droughts can our global economy really sustain? Indeed, some would argue that we risk the collapse of our civilization!

There will be an influence on disease vectors, such as mosquitoes which will thrive in a warmer climate, the range of these vectors and diseases will widen, threatening a much broader area of the globe.

The IPCC has a whole list of unique entities and biological systems at risk of total extinction with a rise of just a few degrees. The breakdown of natural ecological communities will be inevitable as organisms respond to the changing climate at different rates and in different ways.

Countless species, habitats and peoples will be completely wiped out if the Global Warming scenario is allowed to act itself out.