Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

Archives for April 2008

Antarctic Snowfall and Temperature Trends in Global Climate Models

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”We compare new observationally-based data sets of Antarctic near-surface air temperature and snowfall accumulation with 20th century simulations from global climate models (GCMs) that support the Intergovernmental Panel on Climate Change Fourth Assessment Report. Annual Antarctic snowfall accumulation trends in the GCMs agree with observations during 1960–1999, and the sensitivity of snowfall accumulation to near-surface air temperature fluctuations is approximately the same as observed, about 5% K−1. Thus if Antarctic temperatures rise as projected, snowfall increases may partially offset ice sheet mass loss by mitigating an additional 1 mm y−1of global sea level rise by 2100. However, 20th century (1880–1999) annual Antarctic near-surface air temperature trends in the GCMs are about 2.5-to-5 times larger-than-observed, possibly due to the radiative impact of unrealistic increases in water vapor. Resolving the relative contributions of dynamic and radiative forcing on Antarctic temperature variability in GCMs will lead to more robust 21st century projections.”

The above is the abstract from:

Monaghan, A. J., D. H. Bromwich, and D. P. Schneider (2008), Twentieth century Antarctic air temperature and snowfall simulations by IPCC climate models, Geophys. Res. Lett., 35, L07502, doi:10.1029/2007GL032630.

Roger Pielke Sr comments:

“This paper provides further evidence that the multi-decadal global climate models are significantly overstating the water vapor input into the atmosphere, and thus are not providing quantitatively realistic estimates of how the climate system responds to the increase in atmospheric well mixed greenhouse gases in terms of the water vapor feedback. This water vapor feedback is required in order to achieve the amount of warming from radiative forcing projected in the 2007 IPCC report.”

Changing Habitat – A Note from Gavin

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A former resident of Canberra complained today on talkback radio about how the city had become “tatty” during her brief absence. Apparently her family now lives somewhere up the north coast and have green lawns. The difference I reckoned was that the ACT region has missed out again in late autumn with our miserable share of La Nina.

Out on the western fringe of suburbia a few local residents have been watching two strange visitors for a week or so. Opposite my place is another dead tree, a large Eucalyptus nicholii that was planted as a street tree back in the early 1970’s. A few bird droppings on parked cars was the first clue. My neighbor pointed up to some high branches and eventually I recognized the shapes, a pair (?) of tawny frogmouths perched motionless in the higher branches.

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This messy old tree would normally have been condemned as a neighborhood hazard and removed on schedule with many others, however overnight it became “habitat” for what I believe after glimpsing another big wary gray bird on the outer limb late yesterday, two young owls left day by day by their parents.

Despite prying eyes, noisy cars, trucks and machinery underneath these beautifully camouflaged individuals remained seemingly motionless for days. Unfortunately I think a gang of currawongs has finally driven them off.

Note the clear blue sky in my latest photo.

Gavin

Earth’s CO2 Balance

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Using evidence from an Antarctic ice core, Zebee and Caldiera calculated that over a period of 610,000 years the long-term change in atmospheric CO2 concentration was just 22 parts per million volume (ppmv), although there were larger fluctuations associated with the transitions between glacial and interglacial conditions.

By comparison, two centuries of human industry have raised levels by about 100 ppmv.

BBC News website: Nature’s carbon balance confirmed

Nature Geoscience: Close mass balance of long-term carbon fluxes from ice-core CO2 and ocean chemistry records

Richard E. Zeebe & Ken Caldeira

Natural Gas to Replace Oil in Australia?

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The recent prediction by the head of Caltex Australia that the price of oil may very well double the already record highs for crude, have only heightened concerns about the security of Australia’s future fuel supplies. The Federal Government, for instance, has launched a national energy security assessment.

As oil production in Australian fields declines, the Government has also sought and won approval under the United Nations Convention on the law of the sea, to expand its search for oil offshore by an area equivalent to five times the size of France.

But Federal Resources Minister Martin Ferguson agrees that unless there is soon a “eureka oil strike”, Australia must find a new fuel alternative with sufficient reserves to power a vast and vital national car and transport fleet.

But there are those who say there’s an obvious solution to the fuel crisis right under our collective nose, a solution that could cut fuel bills by up to 60 per cent: natural gas.

ABC – The 7.30 Report: Natural gas: the future of fuel?

Mercedes is offering the new Sprinter transporter with natural-gas drive, with operating costs 30 per cent lower than comparable diesel-engined versions.

Drive.com.au: Mercedes van with natural-gas drive

Biofuel Production Criminal: Jean Ziegler

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The United States and the European Union have taken a “criminal path” by contributing to an explosive rise in global food prices through using food crops to produce biofuels, the United Nations special rapporteur on the right to food said today.

At a press conference in Geneva, Jean Ziegler of Switzerland said that fuel policies pursued by the U.S. and the EU were one of the main causes of the current worldwide food crisis.

Ziegler was speaking before a meeting in Bern, Switzerland between UN Secretary-General Ban Ki-moon and the heads of key United Nations agencies.

Ziegler said that last year the United States used a third of its corn crop to create biofuels, while the European Union is planning to have 10 percent of its petrol supplied by biofuels.

The Special Rapporteur has called for a five-year moratorium on the production of biofuels.

Read more here: http://www.ens-newswire.com/ens/apr2008/2008-04-28-03.asp

Satellite Tagged Seals Collect Data from Ocean Around Antarctica

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The latest research from scientists in Antarctica reveals the deep ocean around the frozen continent is becoming less salty and that this could play a major role in changing ocean currents and the climate. New details about changes to salinity are coming from deep beneath the sea ice, courtesy of satellite tagged seals. This unique tracking program involving Australian scientists is part of a major international research program shedding new light on how the world’s oceans are changing.

ABC 7.30 Report Transcript: Satellite tagged seals shed light on climate change

On-line video report also available.