Super Eco

Photo credit: cikaga jamie, flickr

The prognosis for global warming is even bleaker than previously estimated, warns Nicolas Stern, the economist who warned governments in 2006 to brace for the economic impact of climate change. Scientists at an international climate change conference in Copenhagen are urging negotiators for a new United Nations climate agreement to crack down and drive a hard bargain to cope with what appears to be an accelerating situation. But is government getting the big picture?

Understanding the scope of temperature change scientists are now using as a baseline for their discussions may help heat up the debate. Many experts now think the European target of limiting world temperature rise to 2C above pre-industrial levels is no longer an attainable goal. Scientists from the Intergovernmental Panel on Climate Change (IPCC) and Yale University have already warned governments to prepare for a 4C rise. Average temperatures could rise by 6C or even more during this century if greenhouse gas emissions aren't curbed. Stern characterizes an increase in global temperature averages of more than 5C as "likely to lead to major disruption and large-scale movement of population," "catastrophic" and "far outside human experience."

All this talk of numbers gains perspective, given Stern's 2006 scenarios for a 4C worldwide temperature rise:

• 7-300 million more people at risk of coastal flooding every year
• 30-50% reduction in water availability in southern Africa and the Mediterranean
• Agricultural yields down 15%-35% in Africa
• 20%-50% of animal and plant species facing extinction

Just yesterday, scientists projected that a 4C rise would also lead to the loss of 85% of the Amazon rainforest.

At a 5C increase, sea level changes would endanger major cities including New York, London and Tokyo, and increases in ocean acidity would wreak havoc on marine ecosystems. Global warming of more than 5C works out to the amount of warming that occurred between the last ice age and today. We'd shiver—if we still could.