Climate Impacts

  • Stronger evidence of global warming

    With more recent data on the Himalayan glaciers from the Indian Remote Sensing (IRS) satellites, scientists of the Space Applications Centre (SAC) of the Indian Space Research Organisaation (ISRO) at Ahmedabad now have much stronger evidence of the finger print of global warming in the observed alarming retreat of these glaciers. The new results were presented at the ongoing National Space Science Symposium (NSSS-2008) here by Dr. Anil V. Kulkarni of SAC. In 2004 Dr. Kulkarni and his colleagues investigated the spatial extent of 466 glaciers in the basins of Chenab, Parbati and Baspa using remote sensed data and compared them with the 1962 topographic data of the Survey of India. They found an overall reduction of 21 per cent in the glacial surface area. They had also found that the process of deglaciation had led to the fragmentation of large glaciers resulting in the reduction in the mean surface area of glacial extent from 1 sq. km. to 0.32 sq. km. during 1962-2004. The new data pertains to two additional basins of Warwan and Bhut comprising 253 and 189 glaciers respectively. Together with the earlier data on 466 glaciers, the cumulative area of these 908 Himalayan glaciers has been found to have reduced from 3391 sq. km. to 2721 sq. km., implying a total area reduction of 20 per cent. Another new finding is that the snow line

  • Human shadows on world's oceans

    Scientists Are Building First Worldwide Portrait Of Human Impact That Has Left Just 4% Of The Seas Pristine In 1980, after college, I joined the crew of a sailboat partway through a circumnavigation of the globe. Becalmed and roasting one day during a 21-day crossing of the western Indian Ocean, several of us dived over the side. Within a few swimming strokes, the bobbing hull seemed a toy over my shoulder as I glanced back through my diving mask. Below me, my shadow and the boat's dwindled to the vanishing point in the two-mile-deep water. Human activity seemed nothing when set against the sea itself. Just a few weeks later, on an uninhabited island in a remote part of the Red Sea, I was proved wrong. The shore above the tide line was covered with old light bulbs, apparently tossed from the endless parade of ships over the years. Now scientists are building the first worldwide portrait of such dispersed human impacts on the oceans, revealing a planet-spanning mix of depleted resources, degraded ecosystems and disruptive biological blending as species are moved around the globe by accident and intent. A paper in the February 15 issue of the journal Science is the first effort to map 17 kinds of human ocean impacts like organic pollution, including agricultural runoff and sewage; damage from bottomscraping trawls; and intensive traditional fishing along coral reefs. About 40% of ocean areas are strongly affected, and just 4% pristine, according to the review. Polar seas are in the pristine category, but poised for change. Some human impacts are familiar, like damage to coral reefs and mangrove forests through direct actions like construction and subtler ones like the loss of certain fish that shape ecosystems. Others were a surprise, said Benjamin S Halpern, the lead author and a scientist at the National Center for Ecological Analysis and Synthesis in Santa Barbara, California. He said continental shelves and slopes proved to be the most heavily affected areas, particularly along densely populated coasts. The most widespread human fingerprint is a slow drop in the pH of surface waters around the world as a portion of the billions of tons of carbon dioxide added to the atmosphere from fuel and forest burning each year is absorbed in water, where it forms carbonic acid. That progressive shift in ocean chemistry could eventually disrupt shell-forming plankton and reef-building species, particularly where other impacts, including rising temperatures from human-caused global warming, create simultaneous stresses, many marine biologists say. "I study this stuff all the time and didn't expect the impacts to be as pervasive as we found,' Halpern said. The review provides a baseline necessary for tracking further shifts, he said. It also identifies some unanticipated trouble spots, similar to terrestrial biodiversity "hot spots' that environmental groups have identified over the years. NYT NEWS SERVICE

  • Human-induced changes in the hydrology of the western United States

    Observations have shown that the hydrological cycle of the western United States changed significantly over the last half of the 20th century. We present a regional, multivariable climate change detection and attribution study, using a high-resolution hydrologic model forced by global climate models, focusing on the changes that have already affected this primarily arid region with a large and growing population.

  • Soil erosion : A carbon sink or source?

    The report by K.Van Oost et al., "The impact of agricultural soil erosion on the global carbon cycle" (26 October 2007, p. 626) raises two serious concerns. First, the eroded soil is severely depleted of its soil organic matter (SOM) pool, which is preferentially removed by surface runoff because it has low density and is concentrated in the surface layer. Second, the process of soil erosion by water entails three distinct stages : (i) detachment, (ii) transport/redistribution, and (iii) deposition. (Letters)

  • Ocean CO2 studies look beyond coral

    One million tons of atmospheric carbon dioxide are dissolved into the oceans every hour, a process that helps maintain the Earth's delicate carbon balance. But CO2 also makes seawater more acidic, and too much of it can wreak havoc on a marine species.

  • Survival roadmap for climate change

    Calcutta is to have a "detailed, scientific plan' to combat the effects of climate changes, courtesy a World Bank initiative. A three-member team from the bank was in town recently to kick off the project, which will use a simulated model to predict Calcutta's vulnerability to climate changes till 2050 and prepare a survival roadmap. "Calcutta is among the 10 cities in the world that are most vulnerable to climate changes. The Bengal government has okayed a World Bank proposal to launch an initiative to predict the changes,' said state environment secretary K.L. Meena.

  • Mitigation strategies for marine fisheries

    The Central Marine Fisheries Research Institute will evolve mitigation strategies for marine fisheries and develop an ecosystem-based fisheries management technique for sustaining fishery resources, according to its director N.G.K. Pillai. Speaking to The Hindu here on Tuesday, he said the mitigation plan would highlight the impact of climate change on fish species and the shift in the distribution of commercially important varieties like oil sardine that had started migrating in large numbers from the Kerala coast to the northern areas in search of cooler water.

  • King penguin population threatened by Southern Ocean warming

    Seabirds are sensitive indicators of changes in marine ecosystems and might integrate and/or amplify the effects of climate forcing on lower levels in food chains. Current knowledge on the impact of climate changes on penguins is primarily based on Antarctic birds identified by using flipper bands.

  • Climate change may affect quality of life of farmers

    As it hurts agricultural productivity and environment, climate change could also have an adverse impact on the quality of life of farmers and tourism industry, particularly in the developing countries. Climate change will have a telling impact on the farmers. It will be harder for them to carry on in the increased temperatures, Mr M.V.K. Sivakumar, Chief of Agricultural Meteorology Division, WMO (World Meteorological Organisation), told Business Line. Recognising this, the WMO and UN Habitat (the UN body on human settlements) have started working to address this issue, he said.

  • Quite shocking!

    In future, climate change is likely to be the single most significant cause of biodiversity loss, writes Sanjay Gubbi, assessing its overall impact.

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