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大家好，胖胖翔来了！今天的科技文主题是climate change~
Part I：Speaker 【Rephrase1】 Article 1 Fighting Climate Change Also Battles Disease Cutting down on greenhouse gas pollution could deliver health benefits. David Biello reports
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Chances are you won’t die from carbon dioxide. But cutting down on the greenhouse gas pollution responsible for climate change could extend your life and make it better. That's because less reliance on things that produce a lot of CO2, like coal-fired power plants, also means lower levels of other kinds of pollution that shorten lives. That's according to new research in the journal Nature Climate Change. Researchers looked at how CO2 reductions also meant less spewing into the air of fine soot and ozone, otherwise known as smog at ground level. Both soot and ozone have been linked to various respiratory and cardiovascular conditions, such as asthma and heart disease. In other words, soot and smog ain't good for you. Cutting back on the sources of all these types of pollution would mean avoiding more than a million premature deaths by 2050. And that's a conservative estimate because it doesn't include children or anyone under 30, or other factors like the spread of tropical diseases into new regions as the globe warms. In other words, combating climate change ain’t just good for the planet, it's good for your health. —David Biello Source: http://www.scientificamerican.com/podcast/episode.cfm?id=fighting-climate-change-also-battle-13-09-22
Part II：Speed 【Time 2】 Article 2 Climate change may bring dramatic behavior shifts Shifting temperatures and rainfall expected to alter animal lifestyles
BOULDER, Colo. — Warming climate may dramatically change not just where animals live, but how. Solitary sweat bees in northern climes are projected to become builders of social colonies, researchers reported July 31 at the annual meeting of the Animal Behavior Society. Closer to the equator, fitful rainfall may drive tree frogs to exchange plants for ponds as their place to lay eggs.
Previously, researchers found that some animals confronted by changing climate are likely to alter their timing of migration or shift their ranges poleward or up a mountain slope. But a new generation of research is finding that more fundamental changes may occur in animal life history.
In Scotland and Northern Ireland, the sweat bee Halictus rubicundus could largely switch from its solitary life to forming small colonies by 2080, said Roger Schürch of the University of Sussex in England.
The bee, which is widespread across the Northern Hemisphere, adopts a distinctly more social lifestyle in the warmer reaches of its range, including the south of England and Ireland. Each queen emerging in spring lays a batch of largely female eggs, feeding and tending them until they mature into a small workforce, which in turn raises the final generation of the year. The warmth, Schürch said, allows bees to move around briskly and make more foraging runs, which in turn allows bees to raise more offspring.
If transplanted north, however, families of the social southerners turn solitary like their new neighbors. And solitary northerners moved south tend to go social.
Using a program that generates hypothetical future weather under various climate scenarios, Schürch found that with high greenhouse gas emissions Belfast, Northern Ireland, should be toasty enough by about 2050 for its now-solitary bees to raise as many workers as counterparts in southern England do today, he said. And a bit farther north, warming should cause bees in Peebles, Scotland, to go social with southern-sized colonies by 2080.
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【Time 3】
Meanwhile, changing rainfall could affect the lifestyle of a tropical frog, said Justin Touchon of the Smithsonian Tropical Research Institute in Panama. Pantless tree frogs (Dendropsophus ebraccatus) there lay eggs that develop either on land or in the water. The frogs were the first species found to produce dual-habitat clutches.
At shady ponds, the tree frogs often attach their eggs to plants overhanging the water. As long as rain moistens the eggs during their first day they can hatch there, safe from voracious predators in the water. If rain fails to sufficiently wet the eggs that first day, the clutch dies. So around ponds with more open sun beating down, pantless tree frogs often just lay their eggs in the water.
That tendency to take a chance on rainfall grows stronger among pantless tree frogs as precipitation increases southward from Mexico to Ecuador, Touchon reported.
Cloudbursts during the rainy season, when pantless tree frogs breed, may get iffier as the climate changes. Touchon’s earlier work suggests that during the past four decades, rainstorms have become more likely to be skimpier or skip days and leave tree frog eggs to dry out. In response, frog populations may become more likely to lay eggs in water.
These research topics are “very exciting and a new direction,” says behavioral ecologist Timothy C. Roth II of Franklin & Marshall College in Lancaster, Pa. Studying how climate change might affect behavior and mental capacities of organisms, he says, has been “very underrepresented.”
And yes, climate change could affect mental powers, he says. He’s worked with Vladimir Pravosudov of the University of Nevada, Reno on chickadees that appear to need better spatial memory to cope with the harsh northern ends of their ranges. Warming may relax the pressures for the birds to stay as sharp.
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Source: http://www.sciencenews.org/view/generic/id/352161/description/Climate_change_may_bring_dramatic_behavior_shifts
【Time 4】 Article 3 Humans found guilty in climate change International panel's confidence increases that society is responsible for global warming
Scientists are now 95 to 100 percent certain that humans are cranking up the global thermostat.
The boosted confidence in humans’ role in climate change comes from a distillation of thousands of scientific studies, by the United Nations’ Intergovernmental Panel on Climate Change, which released a summary of its findings September 27.
The IPCC, which produces such a report about every six years, had previously estimated only a 90 percent confidence level that human activities, such as burning fossil fuels, are contributing to the world’s rising temperatures. A warmer climate threatens to raise sea level — drowning islands and coastlines — and dramatically alter agriculture and ecosystems around the world.
Global warming and its effects are unequivocal, the panel reports. Since the 1950s, the “atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased,” the panelists wrote.
And now more than ever, the scientists say it is “extremely likely” that humans are to blame.
By burning fossil fuels, people release heat-trapping greenhouse gases such as carbon dioxide into the atmosphere. The panel reports that since the beginning of the industrial era, the atmosphere’s CO2 levels have increased by 40 percent.
At the report’s release in Stockholm, Thomas Stocker, the cochair of the IPCC report, urged action. “In order to limit climate change,” said Stocker of the University of Bern in Switzerland, “it will require substantial and sustained reduction of greenhouse gas emissions.”
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In the report, Stocker and the other authors presented four scenarios describing how current warming trends could play out in the next century, given varying efforts to reduce emissions and mitigate climate change. The panel predicted that by 2100, global average surface temperatures might rise by as little as 0.3 degree Celsius or as much at 4.8 degrees compared with the recent average.
For global average sea level, the panel made a bleaker prediction than previous reports. In the new scenarios, sea level could rise as little as 26 centimeters or as much as 82 centimeters by the end of the century compared with the recent global average. In the IPPC’s last report released in 2007, the range was just 18 to 59 centimeters.
“The data is more certain,” says atmospheric scientist and report coauthor Matilde Rusticucci of the University of Buenos Aires in Argentina. “So we hope the politicians take the message.”
The report also knocks a common argument of those who deny human-caused climate change: that a plateau in the rise of global temperatures over the last 15 years refutes global warming (SN: 10/5/13, p.14). The authors say that climate over such short periods is not indicative of long-term trends, and that extreme weather — like heat waves — at the beginning or end of such time frames may skew data.
Skeptics tend to pick out weather variations over time periods that fit their arguments against global warming trends, says Paul Wapner, an expert in environmental politics at American University in Washington, D.C., who was not part of the panel. “The report makes clear that these trends cannot be questioned.”
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Source: http://www.sciencenews.org/view/generic/id/353565/description/Humans_found_guilty_in_climate_change
【Time 6】 Article 4 Glass Sponges Soak Up Perks of Climate Change
Climate change is a call to action … even for the Antarctic glass sponge. These cream-colored bulbs with intricate silica skeletons (several species within the class Hexactinellida) have been known to bide their time in the icy depths. The creatures, which can be as small as a fist or as big as a smart car, often go decades with no sign of growth or reproduction. But new research shows that their population is exploding, thanks to the collapse of the Larsen Ice Shelf on the Antarctic Peninsula. As temperatures climbed and the icy ceiling above them disintegrated, life got a lot more exciting for these filter feeders. Access to sunlight brought blooms of phytoplankton and new food sources. A team of scientists exploring this part of the Weddell Sea for the first time in 4 years discovered that the glass sponge population had roughly tripled since their last visit. "Glass sponges may find themselves on the winners' side of climate change," they report today in Current Biology. The sponges may not dominate the depths forever, however; other enterprising species could soon prey on them or compete for resources. But their dramatic growth suggests that the ecological shakeup on the sea floor is moving faster than previously thought.
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Source: http://news.sciencemag.org/2013/07/scienceshot-glass-sponges-soak-perks-climate-change
Part III： Obstacle
【Paraphase7】
Article 5 Technology Is Moving Too Slowly to Make Climate-Change Target The IPCC says we can emit a trillion tons of carbon and still avoid major warming. We’ll emit much more.
One of the key findings of the Intergovernmental Panel on Climate Change (IPCC) report released last week was that we need to emit no more than one trillion tons of carbon in order to stand a good chance of limiting global warming to 2 °C. The problem is this: technology is not progressing fast enough to make this happen.
The trillion-ton figure is really an estimate, as no one knows precisely how many tons of carbon will raise the temperature of the planet by 2 °C. And less warming than that could cause significant damage, while humans will probably survive higher levels. That said, the number provides one of the clearest ways of thinking about what most climate scientists believe needs to be done to avert serious climate change.
Unfortunately, we’re on track to hit one trillion tons just 27 years from now. And if we keep increasing the rate of emissions as we have been, we’ll hit it even sooner. To avoid this, the world needs to reduce carbon dioxide emissions by 2.5 percent a year, according to data from climate scientists at Oxford University. That figure seems like a nice, manageable one until you realize what order of change would be required to achieve it.
One of the most remarkable energy transitions in history happened when, starting in earnest in the 1970s, France went from getting 1 percent of its energy from nuclear power to getting 80 percent over a period of just 30 years. As it replaced fossil-burning plants with nuclear ones, the country reduced emissions by only about 2 percent a year, according to David Victor, co-director of the Laboratory on International Law and Regulation at the University of California, San Diego. To come in under the limit, the whole world would need to undergo a similar transition even faster.
Achieving this in the United States, which is struggling to build any nuclear power plants, is hard to imagine. Its transition toward natural gas power from coal is helping. Increased use of natural gas, plus a recession, led to a reduction in carbon dioxide emissions of 6.7 percent in 2009, well in excess of the rate needed to avoid emitting one trillion tons. Unfortunately, emissions jumped 3.8 percent the following year. Over the last 10 years, on average, emissions decreased by just 1 percent per year.
A continued transition to natural gas could help sustain that decrease in the United States for a while. But natural gas power is ultimately a dead end. It can cut emissions in half compared to coal, but it still emits carbon dioxide.
“Long-term ‘sustainable’ emissions of fossil carbon are essentially zero,” says Myles Allen, professor of geosystem science at Oxford University, whose research has helped establish the trillion-ton number.
Allen doesn’t think we have to shut down all the fossil fuel plants. Instead, he’s for capturing carbon dioxide and storing it. But so far, the technology, which could involve capturing the carbon dioxide from a power plant and injecting it into underground reservoirs, hasn’t been demonstrated at a large scale. “It will take decades to work out which reservoirs leak and which don’t, and we won’t get that information until it is deployed at scale,” he says. Only a few demonstrations of CCS are planned, though, and many of those probably won’t go forward (see “EPA Carbon Regs Won’t Help Advance Technology” and “Cheaper Ways to Capture Carbon Dioxide”). The International Energy Agency has warned that demonstrations are “seriously off pace.”
Renewable power is often held up as the way to reduce carbon emissions over the long term. But even with fast growth in recent years, wind and solar account for only about 4 percent of electricity in the United States, and reaching much higher levels will bring challenges. The more that wind and solar power are added to the grid, the more utilities need to spend to deal with their intermittency (see “Wind Turbines, Battery Included, Can Keep Power Supplies Stable”). In one sense, wind power isn’t really zero emissions, since it typically requires backup from natural gas power plants.
To make matters even more difficult, changes would have to be made not only in the power sector, but also in transportation, where alternatives like nuclear power don’t exist. While nuclear power can offer the same kind of consistent, around-the-clock power as fossil fuels, you can’t yet buy a zero-emissions car with the same performance as a gas-powered one.
The closest you can come is probably the Tesla Model S, but that doesn’t go as far per charge as a gas-powered car (265 miles compared to 350 or so), and the existing network of charging options means that in most places in the U.S. you need hours to recharge (“How Tesla Is Driving Electric Car Innovation”). The car also costs $80,000, which means only a few people can afford it. And at any rate, it isn’t really a zero-emissions vehicle because it runs on power from the grid, which comes largely from fossil fuels.
Even assuming grid energy gets considerably cleaner over the next two decades, by 2030 electric vehicles will still involve about one-third the emissions of gas-powered cars when you factor in the emissions from power plants, according to a recent analysis from John Heywood, a professor of mechanical engineering at MIT.
What’s more, given the performance limitations and costs of electric vehicles, they’re unlikely to go mainstream soon, Heywood says. A more realistic scenario, he thinks, is that existing cars will gradually get more efficient as a result of fuel economy regulations, and emissions will be cut in half. But that won’t happen until 2050, in part because cars with existing technology will stay on the roads for decades.
Reducing emissions faster will require people to drive less, or expect less from their vehicles. “It’s very difficult because you have to change people’s behavior,” Heywood says. The same probably goes for reducing emissions throughout the economy.
But the question isn’t really whether we’ll limit emissions to a trillion tons. It seems inevitable that humankind will blow past that goal. The bigger question is how much more carbon will be emitted, given that several trillion tons remain in the ground, waiting to be extracted and burned.
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Source: http://www.technologyreview.com/news/519761/technology-is-moving-too-slowly-to-make-climate-change-target/
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发表于 2013-10-2 08:49:29
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