阅读理解 　　In face of global warming, much effort has been focused on reducing greenhouse gas emissions through a variety of strategies. But while much of the research and innovation has concentrated on finding less-polluting energy alternatives, it may be decades before clean technologies like wind and solar meet a significant portion of our energy needs. 　　In the meantime, the amount of CO2 in the air is rapidly approaching the limits proposed by the Intergovernmental Panel on Climate Change (IPCC). “As long as we’re consuming fossil fuels, we’re putting out CO2,”says Klaus Lackner, a geophysicist at Columbia, University” We cannot let the CO2 in the atmosphere rise indefinitely.” 　　That sense of urgency has increased interest in capturing and storing CO2, which the IPCC says could provide the more than 50% reduction in emissions thought needed to reduce global warming.“We see the potential for capture and storage to play an integral role in reducing emissions,” says Kim Corley, Shell’s senior advisor of CO2 and environmental affairs. That forward thinking strategy is gaining support. The U.S. Department of Energy recently proposed putting $1 billion into a new $2.4 billion coal-burning energy plant. The plant’s carbon-capture technologies would serve as a pilot project for other new coal-burning plants. 　　But what do you do with the gas once you’ve captured it? One option is to put it to new uses. Dakota Gasification of North Dakota captures CO2 at a plant that converts coal into synthetic natural gas. It then ships the gas 200 miles by pipeline to Canada, where it is pumped underground in oil recovery operations. In the Netherlands, Shell delivers CO2 to farmers who pipe it into their greenhouses, increasing their yield of fruits and vegetables. 　　However, scientists say that the scale of CO2 emissions will require vast amounts of long-term storage. Some propose storing the CO2 in coal mines or liquid storage in the ocean, Shell favors storing CO2 in deep geological structures such as saline(盐的) formations and exhausted oil and gas fields that exist throughout the world. 　

问答题 What are suggested as renewable and less-polluting energy alternatives?

问答题 What does the author say is a forward thinking strategy concerning the reduction of CO2 emissions?

问答题 One way of handing the captured CO2 as suggested by the author is to store it and .

问答题 Through using CO2, Dutch farmers have been able to .

问答题 Long-term storage of CO2 is no easy job because of .