IT鈥橲 crunch time. Two years ago in a huge conference hall in Bali, after a marathon negotiating session that left some delegates in tears, envoys from 192 nations set themselves a deadline of 2009. The task in question? To come up with a way of extending the essence of the Kyoto protocol beyond 2012.
The final stages of this process kicked off in Copenhagen, Denmark, on Monday. Delegates now have until 18 December to deliver. We know that the summit won鈥檛 provide a legally binding 鈥淐openhagen protocol鈥�. That will have to wait until 2010. But it must deliver everything else. Key among the expected elements are promises from rich nations to slash their emissions, and from poor nations to slow their emissions growth. Delegates are also expected to agree to channel cash and low-carbon technologies to poorer nations to help them cope with the effects of climate change. It will go to the wire: don鈥檛 expect a conclusion until the early hours of 19 December.
The fate of the planet is not solely in the hands of 192 teams of sleep-deprived politicians, however. Whatever is decided at Copenhagen, environmental awareness has increased, as has funding for low-carbon energy. Pilot projects have sprung up to capture carbon dioxide and store it underground, and alliances have formed to protect ancient forests. A new green revolution has begun, and science has its work cut out over the next decade if it is to deliver a low-carbon society. Here, 快猫短视频 outlines the stepping stones.
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Low-hanging fruit
Say 鈥済lobal warming鈥� and most people think of carbon dioxide. But there are many more pollutants warming our climate, some of them both powerful and easily reduced. These include methane, carbon monoxide, and black carbon 鈥� the fine soot resulting from the incomplete combustion of fossil fuels and the burning of biomass. Warming non-CO2 pollutants have so far contributed as much to global warming as CO2.
The good news is that the technology to cut emissions of non-CO2 pollutants already exists. Fitting black-carbon filters on diesel vehicles worldwide would have an immediate impact on climate, for example. So could capturing methane from landfills. Electrification of rural regions in poor countries and the adoption of solar cookers could immediately reduce soot emissions from homes that use firewood and biomass for heating and cooking. That would improve the health of their occupants to boot.
Anil Ananthaswamy
Location, location, location
In September, climate policy-makers got a shock. Meeting at the World Meteorological Organization in Geneva, Switzerland, they asked scientists to forecast how climate change will pan out country by country. 鈥淣o can do,鈥� came the answer: we are fairly confident about global forecasts, but not local ones.
Will Washington DC be wetter or drier, battered by hurricanes or plagued by drought? 鈥淭he models have to get a lot better before they can do that,鈥� says mathematician Leonard Smith at the University of Oxford. Short-term regional forecasts could in theory be easier than long-term ones, but Philip Duffy of US-based points out that on those timescales, natural variability may cause larger changes than human-made climate change. The politicians are not happy. They want to devise plans for adapting their countries to a changing climate, making it likely that they will push to make local forecasts better.
Fred Pearce
Electric highway
Just a few years ago, 鈥渆lectric vehicle鈥� meant a golf buggy. Then the arrived. The electric sports car does 0-100 kilometres per hour in 4 seconds and has been bought by celebrities such as George Clooney. Finally, electric cars are sexy.
Charging an electric vehicle leads to extra emissions at power plants, but even the Tesla, which is built for speed rather than efficiency, produces less than half of the carbon dioxide per kilometre than the greenest petrol-powered cars. Cheaper, mass-market electric cars are on the way (see picture). The challenge is to get consumers to buy them, which will require a network of stations where drivers can top up their batteries. Enter , an ambitious start-up headed by Israeli entrepreneur Shai Agassi. Better Place is building a charging network in Denmark and says it will have several thousand electric cars on the road by 2011. If it works there, other countries should follow suit.
Jim Giles
Spot the tipping point
The race is on to find climate tipping points before it鈥檚 too late. Beyond them lie runaway warming and collapsing ice sheets. , the Netherlands, argues that increasingly unpredictable and extreme weather 鈥� which modellers call 鈥渇lickering鈥� 鈥� could suggest a big change is imminent. Confusingly, others argue that unexpected sluggishness or stability in the climate could be something to fear: the calm before the storm. Tim Lenton at the University of East Anglia, UK, is working on an early-warning system for climate tipping points. He says the biggest need is for better climate data, to analyse past climatic lurches and spot signs of sluggishness or flickering.
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Hello, solar
By one set of numbers, solar energy is the answer to climate change. The sun throws more energy at the Earth鈥檚 surface in one hour than we use in an entire year. Even at the 15 to 20 per cent efficiency of current solar cells, the US could meet most of its electricity needs by placing solar panels on every suitable roof in the nation.
That hasn鈥檛 happened because electricity from solar cells costs $5000 to $8000 per kilowatt, to coal鈥檚 $1800. That鈥檚 why just one-thousandth of US electricity came from solar sources last year. 鈥淲e have such a long way to go,鈥� says Robert Hawsey at the US National Renewable Energy Laboratory in Golden, Colorado. To get prices down, engineers are building thinner solar cells, which are cheaper, and more flexible versions, which can be incorporated into roofing materials. This sort of progress should make solar cells competitive by 2015, says Hawsey.
JG
Catch that carbon
It鈥檚 a biggie in energy research: capturing the carbon dioxide from power-station emissions and transporting the gas to permanent burial grounds like exhausted salt mines or oil wells. On the face of it, the technology is within reach, and with huge amounts of cheap coal still underground, the world badly needs it. But the logistics of handling billions of tonnes of gas a year are daunting. Pilot projects are under way, but the first commercial carbon capture and storage plants won鈥檛 be in business until 2030 at the earliest, says a report by a team at the Massachusetts Institute of Technology entitled The Future of Coal. And US power generators put the R&D bill at about $20 billion. If we could grow biofuels, burn them and capture the emissions, we could generate energy while sucking CO2 from the atmosphere 鈥� turning global warming into global cooling.
FP
Clouded judgements
When the Intergovernmental Panel on Climate Change says doubling levels of carbon dioxide will probably raise temperatures by 1.5 掳C to 4.5 掳C, most of that error bar is a result of uncertainty over clouds. They鈥檙e too small and short-lived for easy measurement or modelling. Some warm the planet while others cool it. Climate change may create more clouds or fewer. It鈥檚 all very hazy. In July, new work from the US National Center for Atmospheric Research showed global warming is resulting in fewer low clouds over the oceans 鈥� boosting warming. Models are being tweaked to take this into account. NCAR reckon it may soon be time to narrow those errors bars, closing in on 4.5 掳C.
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Biofuels, the sequel
Biofuels have gone from green hero to zero in five years. Many trash rainforests, take land and water that would otherwise be used for growing food, or have carbon footprints as big as the fuels they replace. But it鈥檚 too soon to write them off. The next five years could be make-or-break for developing less antisocial, 鈥渟econd generation鈥� biofuels. Genetically engineered enzymes or chemical catalysts may soon be able to cheaply break down the cellulose in woody agricultural waste into sugars fit for fermentation. Another big breakthrough could be in processing algae grown in tanks or the ocean to turn it into ethanol or butanol.
There will inevitably be physical constraints on how much biofuel can be manufactured, which raises the question of how to best utilise it. If power stations increasingly run on renewable or nuclear fuel, and if future cars are plug-ins charged from the grid, then maybe biofuels should be saved for shipping and applications where charging options are limited.
FP
Change the Earth instead
Call it the planet鈥檚 plan B or call it plain crazy, 鈥済eoengineering鈥� is here to stay. Few serious scientists believe that 鈥渉acking鈥� the climate to artificially cool it is a must, but many think it should investigated seriously. There are growing signs that governments 鈥� and the military 鈥� are paying attention.
It鈥檚 unclear what a plan B would look like. For that, we need to understand the side effects of different schemes. Pumping a sulphur sunshade into the atmosphere, for instance, could disrupt large weather systems. Much of this research can be done with models, but we may also need to carry out 鈥渕icro-hacks鈥� 鈥� small-scale field experiments. The trickiest challenge may be the slippery slope between small-scale experiments and large ones that have a detectable effect on weather or climate, says Ken Caldeira of the Carnegie Institution for Science at Stanford University, California. To avoid groups carrying out their own large-scale experiments unilaterally, it is vital that open discussions on regulation are held soon.
CB
