Diversos sobre assuntos ligados às alterações climáticas:
- Arctic Sea Ice News & Analysis: "Figure 2. The graph above shows daily sea ice extent as of August 17, 2009. The solid light blue line indicates 2009; the solid dark blue line shows 2008; the dashed green line shows 2007; and the solid gray line indicates average extent from 1979 to 2000. The gray area around the average line shows the two standard deviation range of the data. Sea Ice Index data. —Credit: National Snow and Ice Data Center"
- "So many amplifying methane feedbacks, so litle time to stop them all" Climate Progress "The UK’s National Oceanography Centre in Southampton reports: The warming of an Arctic current over the last 30 years has triggered the release of methane, a potent greenhouse gas, from methane hydrate stored in the sediment beneath the seabed."
- As Arctic Ocean warms, megatonnes of methane bubble up: "It's been predicted for years, and now it's happening. Deep in the Arctic Ocean, water warmed by climate change is forcing the release of methane from beneath the sea floor. Over 250 plumes of gas have been discovered bubbling up from the sea floor to the west of the Svalbard archipelago, which lies north of Norway. The bubbles are mostly methane, which is a greenhouse gas much more powerful than carbon dioxide. The methane is probably coming from reserves of methane hydrate beneath the sea bed. These hydrates, also known as clathrates, are water ice with methane molecules embedded in them. The methane plumes were discovered by an expedition aboard the research ship James Clark Ross, led by Tim Minshull of the National Oceanography Centre, Southampton, in the UK."
- "Yvo de Boer of U.N. climate convention says 350 ppm is pipe dream" Grist "“I don’t think there is a hope in hell that people will agree to 350 in Copenhagen. I think we’ll get 2 degrees.” —Yvo de Boer, executive secretary of the United Nations Framework Convention on Climate Change, speaking at a recent meeting with NGO officials. “350” refers to the goal of reducing the concentration of carbon dioxide in the atmosphere to 350 parts per million, while “2 degrees” refers to the goal of keeping the global temperature rise to no more than two degrees Celsius above pre-industrial levels. Both have been discussed as potential targets for a new international climate treaty that will be negotiated in December in Copenhagen."
- Is Northwestern India's breadbasket running out of water?: "The primary reason for such groundwater depletion is irrigation, which has fed the Green Revolution that transformed cereal production in the region and helped sustain a growing population that has reached 114 million people. Between 1970 and 1999 irrigated fields in India tripled in overall extent to cover more than 33 million hectares. That irrigation now looks unsustainable: 'The problem is that groundwater consumption was not capped at a sustainable level and now it will be difficult to curb demand,' Rodell notes. It is also clear that global warming's accelerated melting of the nearby Himalayan glaciers is not the primary culprit in the region's water deficit. These meltwaters feed the rivers of northwestern India and beyond, but that water soon flows out of the area and is lost to it. Even with a generous assumption that all Himalayan glacial melting since 1962 (roughly 13.4 cubic kilometers per year) was concentrated in the 150-kilometer stretch of land closest to the study zone rather than spread across the entirety of the Himalayas, the scientists could explain, at most, 15 percent of the water loss in northwestern India. And the arid region's rainfall levels were above the average of 50 centimeters per year from 2002 to 2008."
- Australia: Farmers face hardship as climate changes: "While politicians are the most visible form of the argument over whether climate change is coming, farmers are living with the reality of it. Extensive research by the CSIRO and the Bureau of Meteorology, backed by dozens of independent studies, establishes that global climate change is extending and intensifying the drought. Water resources are strained now and will decline by 9 per cent to 13 per cent over the next 20 years, according to a CSIRO report, the most detailed yet on the river system. And this forecast is predicated on world leaders agreeing to measures that limit global warming to 2 degrees - an outcome seen as ambitious. The CSIRO analysis tests many scenarios and combinations, and few of them look good. The drought across southern NSW and Victoria - equivalent to the once-in-a-lifetime events that hit Australia in the 1890s and 1930s - may never really ''break'' in the traditional sense."
- Climate change already visible on Greenland: "While scientists can't agree on how much or how fast the Greenland ice sheet will melt, what is certain is that the Arctic is warming up faster than the rest of the planet and that Greenland is already losing a large portion of its ice. As scientists continue to debate and take measurements, the effects of climate change are already visible on the island. [...] Ice as far as the eye can see [...] The boundary between land and ice is striking. At the edge, close to the moraine, ice is a dirty grey color. A half a kilometer on, it's sparkling silvery-white in the Arctic summer sunshine. This far in, the ice is approximately 250 meters thick, according to glacial guide Niklas, who didn't give his last name. In the middle of the ice cap, where the ice is deepest, it is 3.2 kilometers thick. Around 10 years ago, the ice was 40 meters higher than today and the gravel road that leads here from the nearest town, Kangerlussuaq, ran up to the edge of the ice, Niklas said. He added that he isn't sure whether the decrease is a result of climate change, but since climate change has become a popular topic in the media, more visitors have been coming to Greenland. 'They want to see the beautiful country of Greenland,' he said. 'But they want to see if the talk about climate change is correct - and they want to see the ice.'"
- Australia: Study links drought with rising emissions: "Drought experts have for the first time proven a link between rising levels of greenhouse gases and a decline in rainfall. A three-year collaboration between the Bureau of Meteorology and CSIRO has confirmed that the drought is not just a natural dry stretch but a shift related to climate change. Scientists working on the $7 million South Eastern Australian Climate Initiative said the rain had dropped away because the subtropical ridge - a band of high pressure systems that sits over the country's south - had strengthened over the past 13 years. Last year, using sophisticated computer climate models in the United States, the scientists ran simulations with only the ''natural'' influences on temperature, such as differing levels of solar activity. The model results showed no intensification of the subtropical ridge and no decline in rainfall. But when human influences on the atmosphere were added to the simulations - such as greenhouse gases, aerosols and ozone depletion - the models mimicked what has been observed in south-east Australia: strengthening high pressure systems and the significant loss of rain."
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