Archive for July, 2009

July 9, 2009

 

Last updated July 7, 2009 2:48 p.m. PT

Satellite shows big thinning of old Arctic sea ice

By SETH BORENSTEIN
AP SCIENCE WRITER

WASHINGTON — New NASA satellite measurements show that sea ice in the Arctic is more than just shrinking in area, it is dramatically thinning.

The volume of older crucial sea ice in the Arctic has shrunk by 57 percent from the winter of 2004 to 2008. That’s losing more volume of ice than water in Lake Michigan.

NASA scientist Jay Zwally said global warming is to blame. He said rapidly shrinking sea ice in the Arctic warms the rest of the globe indirectly. Older ice is more important in the Arctic because it is thicker, surviving the heat of summer and building over time.

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Gore: Deal on Emissions from Land Useage Change Critical

July 8, 2009

Published on Tuesday, July 7, 2009 by The Times Online/UK

by Robin Pagnamenta, Energy Editor and Ben Webster, Environment Editor

A global deal to cap surging emissions of carbon dioxide from soil will form a critical part of any successful agreement to tackle climate change in Copenhagen later this year, Al Gore said today.

The former US Vice President and environmental campaigner urged world leaders who are set to gather for a UN meeting in the Danish capital in December to recognise the critical importance of soil carbon: an often overlooked part of the debate on global warming.

“There is three times as much carbon in the first two meters of soil than there is in all of the world’s vegetation,” he told an environmental conference at the Smith School in Oxford.

Current estimates indicate that changing land use – including the burning of peatland, the conversion of degraded former forest land to agriculture and desertification through over-farming – is responsible for as much as 30 per cent of the world’s carbon emissions, more than either deforestation, power generation or transport.

Mr Gore cited the example of Indonesia, the world’s third largest emitter of carbon dioxide after China and the US.

He said Indonesia’s high level of emissions were chiefly the result of soil degradation rather than the linked but distinct problem of deforestation.

“Brazil cuts down twice as many trees as Indonesia but Indonesia emits twice as much carbon dioxide as Brazil.”

Much of Indonesia’s tropical rainforest lies on peat soil. After the trees have been cut, the peat is often burnt before the land can be reused – mostly for the creation of palm oil plantations.

The practice releases vast amounts of carbon into the atmosphere and each burning season leaves plumes of smoke hanging over much of southeast Asia for months at a time.
The greenhouse effect is compounding the problem of soil degradation because rising temperatures add to the drying and destruction of carbon-rich soils.

Mr Gore said China was leading the way in trying to “recarbonise” degraded soil through tree planting – an effort which he said needed to intensify globally.

“China now plants two and a half times more trees than the rest of the world put together,” he said.

“Every Chinese citizen between the ages of 6 and 60 has to plant three trees a year.” Soil is the third-largest natural store of carbon in the world after the oceans and fossil fuels such as coal, oil and gas.

Mr Gore expressed optimism that the vast challenge of cutting emissions remained feasible.

“Time is short. Today we will put 70 million tonnes of carbon dioxide into the thin shell of the atmosphere surrounding the planet [but] there is no question that we can solve this crisis.”

Copyright 2009 Times Newspapers Ltd.

Loss of World’s Seagrass Beds Seen Accelerating

July 5, 2009

Published on Friday, July 3, 2009 by Reuters

by Jim Loney

MIAMI – The world’s seagrass meadows, a critical habitat for marine life and profit-maker for the fishing industry, are in decline due to coastal development and the losses are accelerating, according to a new study.

A fishing boat is moored in waters near Nueva Valencia town, Guimaras Island, September 12, 2006. REUTERS/Leo Solinap
Billed as the first comprehensive global assessment of seagrass losses, the study found 58 percent of seagrass meadows are declining and the rate of annual loss has accelerated from about 1 percent per year before 1940 to 7 percent per year since 1990.

Published this week in the Proceedings of the National Academy of Sciences, the study, based on more than 200 surveys and 1,800 observations dating back to 1879, found that seagrasses are disappearing at rates similar to coral reefs and tropical rainforests.

“Seagrasses are disappearing because they live in the same kind of environments that attract people,” James Fourqurean, a professor at Florida International University and a co-author of the study, said in an e-mailed response to questions.

“They live in shallow areas protected from large storm waves, and they are especially prevalent in bays and around river mouths.”

Scientists say seagrass processes waste dumped into the sea, helps stabilize ocean-bottom sediments in coastal areas to reduce erosion, provide nurseries for fish and shellfish and feeding grounds for larger marine creatures, including those that live in coral reefs.

But the grasses can be damaged by polluted water from coastal development, decreasing water clarity, and by dredging and filling of meadows.

The scientists also said global climate change “is predicted to have deleterious effects on seagrasses.” Many scientists believe greenhouse gases are causing the world to warm, leading to a host of environmental effects including warming and rising oceans.

‘ECONOMICALLY AND ECOLOGICALLY IMPORTANT’

Seagrass meadows are important food fisheries and host gamefish like tarpon, permit and bonefish.

A recent study estimated the annual economic value of seagrass at $3,500 per hectare (2.5 acres), Fourqurean said.

“Seagrass beds are at least as economically and ecologically important as tropical forests or coral reefs,” he said.

The study, by a team of scientists from the United States, Australia and Spain, found that 29 percent of known seagrass meadows have disappeared since 1879. Over the entire 130-year period, seagrass was lost at a rate of 1.5 percent per year.

An estimated 19,690 square miles (51,000 square km) of seagrass has been lost since 1879 of a total estimated area of 68,350 square miles (177,000 square km), the researchers said.

“Globally, we lose a seagrass meadow the size of a soccer field every thirty minutes,” said co-author William Dennison of the University of Maryland.

The scientists said 45 percent of the world’s population lives on 5 percent of its land adjacent to the coast.

In the early 20th century, heavy seagrass losses were noted in North America and Europe, where the industrial revolution led to rapid coastal development.

Today, population growth in the regions bordering the Pacific and Indian Oceans are likely leading to the heaviest losses of seagrass, but those regions lack the scientific infrastructure to assess the loss, Fourqurean said.

He said mitigation efforts have had some success in saving and restoring seagrass. For example, in Florida, where treated sewage water is often dumped in the ocean, water managers in Tampa changed their method of treating wastewater and failing seagrasses rebounded.

(Editing by Mohammad Zargham)