Experts Warn of Global Warming ‘Tipping Point’

Washington Post: Now that most scientists agree human activity is causing Earth to warm, the central debate has shifted to whether climate change is progressing so rapidly that, within decades, humans may be helpless to slow or reverse the trend.

This “tipping point” scenario has begun to consume many prominent researchers in the United States and abroad, because the answer could determine how drastically countries need to reduce their greenhouse gas emissions in the coming years. While scientists remain uncertain when such a point might occur, many say it is urgent that policymakers cut global carbon dioxide emissions in half over the next 50 years or risk the triggering of changes that would be irreversible. | story

AP: LONDON – The threat posed by climate change may be greater than previously thought, and global warming is advancing at an unsustainable rate, Prime Minister Tony Blair said in a report published Monday.

The government-commissioned report collates evidence presented at a conference on climate change hosted by Britain’s Meteorological Office last year. It says scientists now have “greater clarity and reduced uncertainty” about the impacts of climate change. | story

Earlier from the NY Times: The top climate scientist at NASA says the Bush administration has tried to stop him from speaking out since he gave a lecture last month calling for prompt reductions in emissions of greenhouse gases linked to global warming.

The scientist, James E. Hansen, longtime director of the agency’s Goddard Institute for Space Studies, said in an interview that officials at NASA headquarters had ordered the public affairs staff to review his coming lectures, papers, postings on the Goddard Web site and requests for interviews from journalists. | story