Today, delegates from the Intergovernmental Panel on Climate Change (or IPCC) overcame economic objections and released a report mapping out measures to combat global warming. The ” Fourth IPCC Assessment Report Summary” was prepared by a United Nations network of 2,000 scientists. It says governments need to act fast to avoid a global climate catastrophe.

Yet some of the world’s biggest emitters of greenhouse gases …(including China, India and the U.S.)… dispute the recommendations. This leaves scientists worried that officials might water down the report due out today.

Some of the scenarios postulated in the report:

• 75-250 million people across Africa could face water shortages by 2020
• Crop yields could increase by 20 percent in East and Southeast Asia, but decrease by up to 30 percent in Central and South Asia
• Agriculture fed by rainfall could drop by 50 percent in some African countries by 2020
• 20-30 percent of all plant and animal species at increased risk of extinction if temperatures rise between 1.5-2.5C
• Glaciers and snow cover expected to decline, reducing water availability in countries supplied by melt water

The report requires unanimous approval by each of the more than 120 governments at the conference, and all changes must be approved by the scientists.  In two other draft reports earlier this year, scientists confirmed that global warming is caused mostly by the accumulation of carbon dioxide and other heat-trapping gases in the atmosphere. They predicted catastrophic consequences unless people stop burning coal, oil and other fossil fuels that produce greenhouse gases.

The latest IPCC report urges countries to take numerous measures.  It suggests they implement more energy-efficient technologies, shift away from the use of dirty coal, and agricultural reforms. The best-case scenario is projected to keep world temperatures from rising more than 3.6 degrees Fahrenheit or 2 degrees Celsius. The report says warming could be kept within this range for the cost of only one-eighth of one percent of annual global GDP .

Fred Pearce is an environment and development consultant and is the author of the book With Speed and Violence: Why Scientists Fear Tipping Points in Climate Change. Fred has written about climate change and environmental issues for nearly two decades. 

Some of you may remember when we spoke with Fred last year about his previous book When the Rivers Run Dry: Water—The Defining Crisis of the Twenty-first Century.

In With Speed and Violence, Fred documents how top scientists, who were once concerned with gradual climate change, now fear abrupt changes due to triggers and hidden tipping points in the environment.

In 2005, even President Bush’s top climate official warned that “…we are on the precipice of climate system tipping points beyond which there is no redemption.”

Over time Fred’s study of human behavior’s effect on the environment has made him more and more pessimistic our climate’s future.