Sunday, February 27, 2011
Saturday, February 26, 2011
Thursday, February 24, 2011
ABC News Online, 25 February 2011
Wednesday, February 23, 2011
I.H.T. SPECIAL REPORT: ENERGY
By BETH GARDINER
New York Times, Published: February 22, 2011
Its backers say it emits only half as much carbon as coal when burned, and some environmentalists agree that it could bridge the gap until cleaner sources slowly come into use.
But opponents see the push for natural gas as a distraction from more pressing priorities, like improving efficiency and generating renewable power.
"We really have to be quite careful about the language we use to frame things," said Kevin Anderson, a professor at the Tyndall Center for Climate Change Research at the University of Manchester in England. "If we call things green, we start to feel positive about it." Natural gas, he said, "is not a positive thing, it's just less negative."
In fact, he called it "a very bad fuel," with "very high emissions indeed."
"They're not as high as some other fossil fuels, but given where we need to be, to compare it with the worst that's out there is very dangerous," he added.
Others are less critical. The Natural Resources Defense Council, an influential environmental group based in New York, wants to see U.S. coal plants converted to natural gas, said Kate Sinding, a senior attorney with the council.
Reducing energy demand and promoting renewables come first, she said, "but we do see that as we get there, there is inevitably going to be a role for natural gas to play."
In addition to the carbon dioxide savings, natural gas also emits far lower levels of pollutants like nitrogen and sulfur oxides, mercury and particulate matter. Eventually, Ms. Sinding said, natural gas plants could be paired with solar and wind farms, which generate intermittent supply and need backup.
Still, even if gas burns more cleanly than coal and oil, its production is often so dirty that it undermines the environmental gains, she said. U.S. and state regulators must tighten rules that have failed to reduce the serious problem of methane leaks and protect the quality of air and drinking water, Ms. Sinding said.
Natural gas is composed largely of methane, which, if leaked unburned, is a powerful greenhouse gas. Also, poorly built gas wells can contaminate nearby aquifers.
"In theory it can be reasonable, but we're just falling far short of what we need to be doing for it to realize its promise," she said.
Much of the enthusiasm in the United States and Europe for natural gas comes from its relative abundance, and its location in places friendly to the West. The United States in particular has plentiful supplies, now that extraction from shale rock has boomed into a big industry.
"Gas is much better distributed around the world than oil," said Michael Webber, associate director of the Center for International Energy and Environmental Policy at the University of Texas at Austin. "We keep finding it."
Many environmentalists are not convinced, noting that a growing number of new finds are in hard-to-reach areas or require unconventional forms of extraction, making exploitation riskier, more expensive and more energy-intensive.
Still, Mr. Webber said, "If we can really produce gas in a safe, clean way and it's as abundant as people say, it doesn't take us all the way to a zero-carbon future, but it's clearly a big step in the right direction."
The advantages of gas, which include the low capital cost and short turnaround time for building new plants, make it essential for reducing carbon emissions quickly, said Beate Raabe, director of European Union affairs at the International Association of Oil and Gas Producers, a trade group based in Brussels.
In the longer term, she said, carbon-capture technology could make gas plants part of a green future.
Mr. Obama appeared to share such optimism when he mentioned natural gas in his State of the Union speech last month, surprising environmentalists by listing it along with solar, wind, nuclear and so-called clean coal power as key parts of a national clean-energy strategy.
But some remain skeptical of the idea that natural gas can serve as a bridge to a cleaner renewable energy future.
"How long and how wide is this bridge?" asked Ms. Sinding, of the Natural Resources Defense Council. "The more we put into natural gas, the greater the concern that we lock ourselves into burning natural gas and not substituting for it."
Friday, February 18, 2011
Cause for confidence
Thursday, February 17, 2011
By Brian Vastag
The Washington Post, 16 February 2011
Human emissions of carbon dioxide and other greenhouse gases helped trigger the increase in extreme rain events seen in North America over the second half of the 20th century, a group of climate scientists reported Wednesday in the journal Nature.
In a second Nature paper, another group reported that human greenhouse gas emissions likely contributed to the horrendous floods that inundated England and Wales in the fall of 2000. Those scientists ran sophisticated climate simulations across a network of tens of thousands of home computers that volunteers loaded with climate-modeling software.
"Human influence on the climate system has the effect of intensifying precipitation extremes," said Francis Zwiers, a climate researcher at Environment Canada in Toronto and lead researcher on the first study.
Zwiers and his team gathered 50 years of rainfall statistics, and compared those observations to predictions made by computer simulations of the 20th century climate.
Those simulations included the warming impact of the billions of tons of carbon dioxide human society has pumped into the atmosphere.
The study found that observed increase in deluges "cannot be explained by natural internal fluctuations of the climate system alone," said Zwiers. In other words, only the addition of greenhouse gases to the atmosphere explains why the United States and Canada have experienced a dramatic increase in heavy downpours.
"Large [rainfall] events are becoming larger," Zwiers said. His work found that from 1951 to 1999, the probability of heavy downpours becoming even more extreme grew by about 7 percent, a figure he characterized as "really substantial."
Richard Allan, a climate scientist at the University of Reading in England who was not part of the study, called the method employed by Zwiers "very rigorous."
He added, "There's already been quite a bit of evidence showing that there has been an intensification of rainfall" events across the globe.
But until now "there had not been a study that formally identified this human effect on precipitation extremes," Zwiers said. "This paper provides specific scientific evidence that this is indeed the case."
The explanation is simple physics: Warmer air holds more water vapor. That means when rainfall gets triggered, the air contributing to the storm is holding more water than it did in the cooler pre-industrial world.
In the second study, Pardeep Pall from the University of Oxford led an international team that found "human [greenhouse gas] emissions substantially increased the odds of floods occurring in what was the record wet autumn of 2000."
The floods that inundated the United Kingdom that year were the worst since at least 1766.
Pall's conclusion springs from two sets of many thousands of computer weather simulations. The first set simulated the atmosphere in its real state - loaded with all the extra carbon dioxide humans have added to it. The second set simulated a parallel world where no extra carbon dioxide had been added to the atmosphere.
The odds of the massive floods occurring in the no-extra-greenhouse-gases parallel world were about half the odds of the floods happening in the real world, Pall said.
Tens of thousands of volunteers loaded climate-predicting software onto their home computers via the Web site climateprediction.net, Pall said, providing a vital boost in computer power needed to run the many thousands of climate simulations.
The climateprediction.net project has been running for several years. As of Wednesday morning, some 54,000 computers around the world were helping climate scientists crunch data. The donated computer time has completed 118 million years of climate simulations, according to the climateprediction.net website.
The research could not absolutely determine that the floods had been triggered by greenhouse gases, said the University of Oxford's Myles Allen, who contributed to the study. "It's important to stress there is uncertainty in this work."
With the number and intensity of extreme deluges expected to climb, climate scientists and meteorologist are rushing to build better flood prediction systems, particularly for the developing world. On Monday,The Post reported on one scientist's assertion that last summer's floods in Pakistan could have been predicted - and the populace warned - if available data had been heeded.