The European Commission has called for a global carbon trading market as part of a plan to tackle climate change.

    The EU is already committed to expanding its Emissions Trading Scheme (ETS), but now it is urging other industrialised countries to join in.

    The commission says that by 2015 it wants to link the ETS to other carbon trading systems. The goal is to include emerging economies by 2020.

    A UN climate conference in Copenhagen in December is to strive for a deal.

    The commission proposals presented on Wednesday are designed as the EU's contribution to the UN debate, with the aim of getting a new global pact on measures to tackle climate change.

    The pact would be a successor to the 1997 Kyoto Protocol, which was not ratified by the US, the world's biggest polluter.

    As carbon dioxide emissions continue to rise, the world will experience more and more long-term environmental disruption. The damage will persist even when, and if, emissions are brought under control, says study author Susan Solomon, who is among the world's top climate scientists.

    "We're used to thinking about pollution problems as things that we can fix," Solomon says. "Smog, we just cut back and everything will be better later. Or haze, you know, it'll go away pretty quickly."

    That's the case for some of the gases that contribute to climate change, such as methane and nitrous oxide. But as Solomon and colleagues suggest in a new study published in the Proceedings of the National Academy of Sciences, it is not true for the most abundant greenhouse gas: carbon dioxide. Turning off the carbon dioxide emissions won't stop global warming.

    "People have imagined that if we stopped emitting carbon dioxide that the climate would go back to normal in 100 years or 200 years. What we're showing here is that's not right. It's essentially an irreversible change that will last for more than a thousand years," Solomon says.

    This is because the oceans are currently soaking up a lot of the planet's excess heat - and a lot of the carbon dioxide put into the air. The carbon dioxide and heat will eventually start coming out of the ocean. And that will tak' place for many hundreds of years.

    Sacramento - California officials say they plan to enforce the state's regulation requiring the nation's most fuel-efficient vehicles as soon as the federal government grants the state a waiver from less-stringent national standards. The move is expected this spring.

    The regulation would have the single largest impact on the state's ambitious goal to reduce greenhouse gas emissions by 30 percent by 2020 under the landmark legislation AB32.

    Delayed by the Bush administration since 2005, the rule would require automakers to produce vehicles that cut greenhouse gas emissions by 30 percent by 2016, resulting in an average vehicle fuel-efficiency of 35.7 miles per gallon - far higher than the current federal standard of 27.5 mpg for cars and 22.3 mpg for SUVs and light trucks.

    The rule would have wide-ranging impact on the types of cars, minivans, SUVs and trucks that consumers will see in California dealerships.

    President Obama ordered his environmental officials on Monday to immediately review California's regulation, strongly hinting that he would like to allow the state and 13 others to move forward with stricter emissions standards. The federal government, under former President Bush, refused to grant the waiver in 2007 after two years of deliberation.

    Studies find wide range of tree species are dying with serious long-term effects for biodiversity and carbon dioxide release.

    Trees in the western United States are dying twice as quickly as they did three decades ago and scientists think global warming is to blame.

    In their surveys, ecologists found that a wide range of tree species were dying including pines, firs and hemlocks and at a variety of altitudes. The changes can have serious long-term effects including reducing biodiversity and turning western forests into a source of carbon dioxide as they die and decompose. That could lead to a runaway effect that speeds up climate change.

    "The trend was pervasive across a wide variety of forest types, across all elevations, in trees of all sizes and among major species," said Phillip van Mantgem of the US Geological Survey (USGS). "At the same time, the rate of new establishment of trees didn't change."

    If these trends continued, he said, forests will become sparser and store less carbon. "It introduces the possibility that western forests could be come net sources or carbon dioxide to the atmosphere, further speeding up global warming."

    Eight years of Bush inaction leave Obama with a near-impossible challenge.

    Given the sheer number of candidates for "worst legacy of the Bush years," it may seem perverse to pick the hundreds of coal-fired power plants that have opened across China during his administration. But given their cumulative effect - quite possibly the concrete block that broke the climate-camel's already straining back - I think they may be what history someday seizes on. And they are emblematic of George W. Bush's utter failure to help the world rein in carbon emissions at what may have been the last possible moment.

    When Bush first took office, China (and really India as well) were right at the bottom of their energy takeoff. China had actually become steadily more energy efficient over the previous decade, as absurd state industries began to shut down. But both countries were poised, thanks to the creation of the World Trade Organization, for the true explosion of their export economies, and for the subsequent rapid migration of rural residents to the factory cities that became the largest exodus in human history.

    The obvious, easy, and cheap candidate to power that boom was always going to be coal: China has its own vast stockpiles and the kind of labor force and rail links to make exploiting it relatively easy. But by 2000 we already knew enough to conclude just how dangerous it would be if China went whole-hog into the coal business. George W., remember, had pledged during the 2000 campaign that he would enact a "four-pollutant bill" for America's own coal-fired power plants, forcing them to start reducing carbon dioxide.

    But Bush abandoned that plan within weeks of taking office, kneecapping Christine Todd Whitman, his EPA chief, just before her first foreign trip. She grinned and took it, and the rest of the world winced and took it. From that day forward there was no real chance that the world would make substantive progress against carbon during the Bush years.