Researchers say they have an answer to a question that’s been befuddling climate scientists for years: Was it possible that Antarctica, alone among the earth’s seven continents, wasn’t feeling the effects of global warming? As recently as 2007, the Intergovernmental Panel on Climate Change declared that the jury was still out on the question, but now, finally, researchers say they have conclusive proof that the icy southern continent is also heating up. In October, a separate group of researchers came to much the same conclusion using computer models, but the new study bolsters previous research with empirical evidence.
The confusion over conditions in Antarctica arose mostly from strange weather patterns created by ozone depletion in the Southern Hemisphere, and allowed “climate skeptics” who deny the existence of global warming to use the continent as a talking point. Scientists had long thought that while some isolated parts of Antarctica had been warming, much of the continent had been cooling over the past 50 years. But the new analysis found that since 1957, when measured as a whole, the continent’s temperature has risen about 1 degree Fahrenheit. “The thing you hear all the time is that Antarctica is cooling — and that’s not the case,” says study lead author Eric Steig [USA Today].
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Several new studies of ice loss at the earth’s poles paint a distressing picture of global warming‘s impact on those fragile ecosystems, and one study warns that changes in the Arctic climate can have a large impact on the rest of the world. In the first study, researchers determined that more than 2 trillion tons of landlocked ice in Greenland, Alaska, and Antarctica have melted since 2003, a melting trend that researchers expect to continue. Using new satellite technology that measures changes in mass in mountain glaciers and ice sheets, NASA geophysicist Scott Luthcke concluded that the losses amounted to enough water to fill the Chesapeake Bay 21 times. “The ice tells us in a very real way how the climate is changing,” said Luthcke [CNN].
Melting of land ice, unlike sea ice, increases sea levels very slightly. Between Greenland, Antarctica and Alaska, melting land ice has raised global sea levels about one-fifth of an inch in the past five years, Luthcke said. Sea levels also rise from water expanding as it warms [AP]. The amount by which sea levels will rise as a result of global warming is still uncertain. The UN’s Intergovernmental Panel on Climate Change gives an official estimate of a seven-inch to two-foot rise by 2100, but researchers say conditions at the poles are changing too quickly for confident predictions.
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If life gives you saltwater, grow salt-loving plants. That’s the cheerful prescription two ecologists have offered to cope with the salinization of coastal fresh water supplies that would likely occur if global warming causes sea levels to rise, bringing saltwater sloshing further inland. The scientists say that convincing farmers to grow edible salt-tolerant plants would prepare them for changing conditions, and would also allow them to utilize previously barren coastal deserts and degraded agricultural land.
Governments should begin to invest in “saltwater agriculture,” says coauthor Jelte Rozema. “We have limited amounts of freshwater – most of it is used for drinking water. Gradually it will be profitable to think of brackish water and sea water as a resource.” … The scientists suggest the best way forward is to domesticate wild plants, crossbreeding them to produce higher yields [BBC News]. Researchers points to edible plants like sea kale and samphire (sometimes called sea asparagus) as likely candidates for domestication, as both grow happily amid the sea spray. In the Netherlands, researchers have experimented with growing sea kale as a crop in coastal areas, and their results have been a hit at one island restaurant. “It has a stronger flavor than most vegetables but brings out very nice accents in food,” [restaurateur Jef] Schuur said. “Growing sea kale here shows that there are a lot more opportunities for local produce on low-lying islands affected by salt” [Bloomberg].
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The newly elected president of the Maldives, the island chain south of India, says his country must start saving up money to buy a new homeland, in case global warming causes sea levels to rise so much that the waves submerge the archipelago entirely. Says Maldivian President Mohamed Nasheed: “We can do nothing to stop climate change on our own and so we have to buy land elsewhere. It’s an insurance policy for the worst possible outcome…. We do not want to leave the Maldives, but we also do not want to be climate refugees living in tents for decades,” he said [The Guardian].
The Maldives are the lowest-lying nation on the planet: most of the islands are only a few feet above sea level, and the highest point, in the capital city of Malé, is about seven feet above sea level. But the white sandy beaches are a major tourist attraction bringing in billions of dollars every year…. Mr Nasheed’s plan is to create a “sovereign wealth fund” using tourism revenues to buy land so that future generations will have somewhere to rebuild their lives if they have to leave. He wants somewhere within the region, where the culture is similar – possibly India or Sri Lanka [BBC News]. However, Nasheed also mentioned Australia as a possibility, because of the vast swaths of unoccupied land on that continent.
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A new analysis of Antarctic weather conditions has found that human-caused global warming is to blame for the changing climate at the south pole, according to a new study. In its landmark Fourth Assessment Report, the Intergovernmental Panel on Climate Change (IPCC) declared in 2007 that human influence on climate “has been detected in every continent except Antarctica” [Nature News]. Now, researchers have evidence that even that final frontier is feeling the heat from human activities.
In the study, published in Nature Geoscience [subscription required], researchers compared 100 years of Antarctic and Arctic climate records to the results of two sets of computerized climate models. Both sets factored in the effects of natural phenomena, such [as] volcanic eruptions and solar sunspot cycles, but only one set factored in the consequences of human activities that can affect climate, such as rising levels of the greenhouse gas carbon dioxide and fluctuations in the amount of ozone in the stratosphere. It was the models which included human factors that most closely matched the temperature profiles recorded at the poles. “For me, it can’t be more clear that human activity is responsible” [New Scientist], said study coauthor Alexey Karpechko.
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Climate scientists have long predicted that global warming will melt polar ice sheets and cause sea levels to rise throughout the century, potentially swamping island nations and flooding low-lying coastal cities. But exactly how much ocean waters will rise has yet to be settled. Now, two studies have come out that at first appear to contradict each other, leading to clashing headlines like “An Inconvenient Truth” Exaggerated Sea Level Rise [Telegraph], and Sea Level Rise May Be Twice More Than Expected [Discovery News].
One study seems to downplay the risk of an extreme sea-level rise, while the other hypes it up. But a closer look reveals that the two studies actually bring researchers nearer to scientific consensus.
In the study published in Science [subscription required], researchers examined the hypothesis of a six-foot sea-level rise by 2100, and calculated how quickly the ice sheets in Greenland and Antarctica would have to melt into the oceans to produce this effect. Their calculations showed that the glaciers would have to essentially gallop towards the sea, which seems an unlikely outcome. In Greenland, the glaciers moving into the island’s calving fjords would have to increase their speed to 28.4 miles per year and sustain that speed until the end of the century [Telegraph]. These researchers believe the most plausible scenario is a sea-level rise of between two and six feet within this century. As their results have been compared to more radical estimates like the 20-foot rise mentioned in the documentary film An Inconvenient Truth, the findings are being greeted with relief.
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