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Sunday, January 3, 2010

Permafrost thaw may accelerate Arctic groundwater runoff

They ran the simulation under three scenarios, starting with three initial surface temperatures (-2, -1.5, and -1 degrees Celsius, or 28.4, 29.3 and 30.2 degrees Fahrenheit), corresponding to different permafrost thicknesses. In each case, they increased the average seasonal surface temperature by 3 degrees C (5.4 degrees F) over 100 years, an average of model predictions for temperature increase in the Arctic over the next century.
After the warming period, in each scenario the temperature was then held constant for the next 1100 years.
The authors found that although the initial distribution of ice influences the response, in all cases groundwater flow to streams and rivers accelerates over time. In fact, the results indicate that substantial increases in groundwater flow are likely over the next few centuries even if surface air temperatures stabilize at current levels.
The research is published in Geophysical Research Letters. Authors include V. F. Bense: School of Environmental Sciences, University of East Anglia, Norwich, UK; G. Ferguson: Department of Earth Sciences, Saint Francis Xavier University, Antigonish, Nova Scotia, Canada; H. Kooi: Faculty of Earth and Life Sciences, VU University, Amsterdam, Permafrost thaw may accelerate Arctic groundwater runoff

Global Warming: Is making carbon 'SAFE' the answer?

The concept, called SAFE (Sequestered Adequate Fraction of Extracted) carbon, is put forward by scientists from Oxford University and the University of Wyoming in a Commentary article published online today in a special issue of Nature Geoscience focusing on carbon sequestration.
The researchers suggest that fossil fuel producers could be mandated to sequester a steadily increasing fraction of the carbon they extract from the ground, with the fraction set to reach 100 per cent before total emissions into the atmosphere exceed an agreed total, with the costs passed on to fossil fuel consumers.
Their work explores the policy implications of research published earlier this year which showed that it is the total amount of carbon released into the atmosphere over all time that principally determines the risk of dangerous climate change, not the rate of emission in any given year.
'The neat thing about SAFE carbon is that is breaks the apparent conflict between short-term economic development and long-term climate protection,' said Dr Myles Allen of Oxford University's Department of Physics, an author of the paper with Dr David Frame, of Oxford University's Smith School of Enterprise and the Environment, and Chuck Mason, of the Department of Economics and Finance at the University of Wyoming.
Dr Allen added: 'We would no longer be asking a country like India to accept limits on their consumption. Instead, we would be saying that as long as you use SAFE carbon, you can go ahead and consume as much as you like. Of course, unlike a comprehensive emission permit or carbon tax regime, mandatory sequestration would not generate massive new government revenues or provide a mechanism for modifying consumer behaviour, but depending on your political perspective, that might be considered a good thing. We didn't save the Ozone Layer by rationing deodorant.'Global Warming: Is making carbon 'SAFE' the answer?

Northern South America rainier during Little Ice Age

The authors analyzed two new records of oxygen isotopes (which track precipitation levels) from cave formations in northeastern Peru. They attribute the higher rainfall in northern South America during the LIA to cooler spring sea surface temperatures in the tropical North Atlantic.
Furthermore, the authors note that some studies have shown that during the twentieth century, a significant amount of rainfall variability in northern South America was related to the El Niño-Southern Oscillation (ENSO), with higher rainfall occurring during La Niña conditions.
However, the authors determine that the ENSO was probably not as significant an influence on rainfall during that time period as it is now.
The authors suggest that the results point to a need to reevaluate some ideas about hydroclimate change over South America during the past millennia.
The research is published in Geophysical Research Letters. Authors: Justin Reuter, Lowell Stott, and Deborah Khider: Department of Earth Sciences, University of Southern California, Los Angeles, California, USA; Ashish Sinha: Department of Earth Sciences, California State University, Carson, California, USA; and Hai Cheng and R. Lawrence Edwards: Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota, USA.
Northern South America rainier during Little Ice Age

Indian Ocean climate event recurs quicker with global warming

To learn more about IOD patterns, Nakamura et al. studied a 115-year coral record from Kenya. They analyzed coral oxygen isotope ratios, which trace rainfall anomalies, to reconstruct IOD variability. The results add to evidence that the IOD has been occurring more frequently in recent decades. The researchers find that before 1924, the IOD occurred approximately every 10 years, but since 1960, IOD events have been occurring approximately 18 months to 3 years apart.
The authors suggest that global warming effects on the western Indian Ocean have driven the observed shift in IOD variability and note that the IOD has replaced the El Niño-Southern Oscillation as the major driver of climate patterns over the Indian Ocean region.
The research is published in Geophysical Research Letters. Authors include Nobuko Nakamura, Hajime Kayanne, Hiroko Iijima, and Toshio Yamagata: Department of Earth and Planetary Science, University of Tokyo, Tokyo, Japan; Timothy R. McClanahan: Marine Programs, Wildlife Conservation Society, New York, New York, USA; and Swadhin K. Behera: Frontier Research Center for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan.

Indian Ocean climate event recurs quicker with global warming