Tiempo Climate Newswatch

Writing in Conservation Letters, Will Turner of Conservation International and his collaborators argue that, unless we plan properly, the manner in which humanity responds to the climate problem may cause more damage than climate change itself. "Climate change mitigation and adaptation are essential," Turner comments. "We have to reduce emissions, we have to ensure the stability of food supplies jeopardized by climate change, we have to help people survive severe weather events - but we must plan these things so that we don't destroy life-sustaining forests, wetlands, and oceans in the process."

Turner cites the example of the Indian Ocean tsunami in 2004. Although this was not a climate event, he acknowledges, many of the responses that it stimulated are comparable with how people will react to extreme weather and climate. "The damage that the response to the tsunami did to many of Aceh province's important ecosystems as a result of extraction of timber and other building materials, and poor choices of locations for building, should be a lesson to us all," he warns. The authors note that one fifth of the world's remaining tropical forests lie within 50km of human population centres that could be inundated if sea levels rise by one metre. About half of all Alliance for Zero Extinction sites - which contain the last surviving members of certain species - are also in these zones. These forests and their resources would be a likely destination of populations forced to move away from the coast.

Even a modest rise in daily minimum temperature could adversely affect Asian rice production, according to an international team of researchers. "If we cannot change our rice production methods or develop new rice strains that can withstand higher temperatures, there will be a loss in rice production over the next few decades as days and nights get hotter," warned team leader Jarrod Welch of the University of California, San Diego. Rice is the staple food to some 600 million people in Asia.

The analysis was based on the link between daily minimum and maximum temperatures and irrigated rice production during the period 1994-1999 at over two hundred sites in China, India, Indonesia, the Philippines, Thailand and Vietnam. "As the daily minimum temperature increases, or as nights get hotter, rice yields drop," Welch said. "Up to a point, higher daytime temperatures can increase rice yield but future yield losses caused by higher night-time temperatures will likely outweigh any such gains because temperatures are rising faster at night," he continued.

Richard Alley, a geoscientist at Pennsylvania State University, has warned the United States House of Representatives committee on energy independence and global warming that a global sea-level rise of seven metres is a realistic possibility. Alley is concerned that the world is rapidly approaching a tipping point, a temperature rise of somewhere between two and seven degrees Celsius, that would force the loss of major ice masses such as the Greenland ice sheet. "Some time in the next decade we may pass that tipping point, which would put us warmer than temperatures that Greenland can survive," Alley said.

John Church at Australia's Commonwealth Scientific and Industrial Research Organisation, who has acted as a lead author on sea-level rise for the Intergovernmental Panel on Climate Change, broadly agrees with the assessment. "We are seeing something significant, and it's something our coastal cities have not experienced before," he said. "We're beginning to move outside the range of what we have become used to seeing as normal variability, and see an acceleration of both greenhouse gas levels and sea-level rise." He did, however, stress that there remains considerable uncertainty regarding the potential loss of the Greenland ice. "We are looking at a process that will be going on for centuries," he commented. "It may be that we do cross that threshold relatively soon, but there is a lot of uncertainty around it, in my view."