Nuclear power
The world’s first large-scale nuclear power plant opened at Calder Hall in Cumbria, England, in 1956 and produced electricity for 47 years.
Two-thirds of the Arctic coastline is made of permafrost — an environment that is very sensitive to warming temperatures. A new report says erosion is causing these coastline regions to recede by an average of 1.5 feet per year.
Unlike rock shoreline, permafrost loses its structure when it warms above freezing. “Surface air temperatures have reached record levels over the past decade,” the report from an international consortium found. Combine this with weakened permafrost and there’s a recipe for erosion.
RIO DE JANEIRO — A widespread drought in the Amazon rain forest last year was worse than the “once-in-a-century” dry spell in 2005 and may have a bigger impact on global warming than the United States does in a year, British and Brazilian scientists said on Thursday.
More frequent severe droughts like those in 2005 and 2010 risk turning the world’s largest rain forest from a sponge that absorbs carbon emissions into a source of the gases, accelerating global warming, the report found.
Trees and other vegetation in the world’s forests soak up heat-trapping carbon dioxide as they grow, helping cool the planet, but release it when they die and rot.
“If events like this happen more often, the Amazon rain forest would reach a point where it shifts from being a valuable carbon sink slowing climate change to a major source of greenhouse gases that could speed it up,” said lead author Simon Lewis, an ecologist at the University of Leeds.
The study, published in the journal Science, found that last year’s drought caused rainfall shortages over a 1.16 million square-mile expanse of the forest, compared with 734,000 square miles in the 2005 drought.
It was also more intense, causing higher tree mortality and having three major epicenters, whereas the 2005 drought was mainly focused in the southwestern Amazon.
As a result, the study predicted the Amazon forest would not absorb its usual 1.5 billion metric tons of carbon dioxide from the atmosphere in both 2010 and 2011. In addition, the dead and dying trees would release 5 billion metric tons of the gas in the coming years, making a total impact of about 8 billion metric tons, according to the study.
In comparison, the United States emitted 5.4 billion metric tons of carbon dioxide from fossil fuel use in 2009.
The combined emissions caused by the two droughts were probably enough to have canceled out the carbon absorbed by the forest over the past 10 years, the study found.
The widespread drought last year dried up major rivers in the Amazon and isolated thousands of people who depend on boat transportation, shocking climate scientists who had billed the 2005 drought as a once-in-a-century event.
The two intense dry spells fit predictions by some climate models that the forest will face greater weather extremes this century, with more intense droughts making it more vulnerable to fires, which in turn could damage its ability to recover.
Under the more extreme scenarios, large parts of the forest could turn into a savannah-like ecosystem by the middle of the century with much lower levels of animal and plant biodiversity. Although human-caused deforestation in Brazil has fallen sharply in recent years, scientists say the forest is still vulnerable.
A crucial question is whether the droughts are being driven by higher levels of greenhouse gases or are an anomaly, Lewis said. If they are driven by global warming, a vicious cycle of warmer temperatures and droughts could conceivably lead to a large-scale transformation of the forest over a period of decades.
“You could quite rapidly move to a much drier Amazon with less forest there,” Lewis told Reuters.
The research was a collaboration among scientists at the University of Leeds and the University of Sheffield in Britain and Brazil’s Amazon Environmental Research Institute.
The loss of a massive “tongue” of glacial ice on the Antarctic coast — a natural protective barrier nearly four times the size of New York City — could affect ocean circulation patterns and be a harbinger of changes to come from global warming, scientists on a mission to the frozen continent say.
Last February, the tongue of Antarctica’s Mertz Glacier was rammed by a huge iceberg, causing the tongue section to break away and itself become an iceberg.
The tongue, sticking out into the Southern Ocean, had acted like a dam, preventing sea ice from moving into a permanently open section of water to the west.
But now, with the tongue gone due the collision, scientists fear it could trigger changes to the behavior of a major part of global ocean circulation patterns that shift heat around the globe via myriad currents at the surface and along the bottom.
The area around the glacier tongue, since halved in length by the collision, and to the west are one of the few places around Antarctica where dense, salty water is formed and sinks to the depths of the ocean, said mission leader Steve Rintoul.
This dense “bottom water” is a key driver of the global overturning circulation that includes the current that brings warm Atlantic waters to western Europe.
But he said there was a risk the area could now be less effective in producing the bottom water that feeds the deep ocean currents, which influence global climate patterns.
“This is one of the few places around Antarctica where the sea surface is made dense enough to sink to the deep ocean,” Rintoul said from the icebreaker Aurora Australis.
“If the area is less effective in forming less dense water, then that salinity now should be lower than it was in the past.”
Rintoul is leading an international team of nearly 40 scientists on a voyage studying the impacts of the loss of the glacier tongue as well as changes to ocean temperatures, salinity and acidity.
Oceans act as a brake on climate change by soaking up large amounts of heat and carbon dioxide, the main greenhouse gas, from the atmosphere. But the more CO2 the oceans take up, the more acidic they become, making it harder for animals such as sea snails to make their shells.
Rintoul, an oceanographer with the Antarctic Climate and Ecosystems Cooperative Research Centre in Hobart, Australia, said the area around the glacier remains free of ice all winter. Such areas are called polynas.
“It remains free of ice because the winds blowing off the continent are so strong it blows the ice away as rapidly as it forms,” he said.
“So in that sense, it is kind of a sea-ice factory and the more sea ice that is formed, the saltier the water beneath the sea ice becomes,” leading to the creation of dense, salty water, he added.
“We think the presence of the glacier tongue was part of what made this a very active polyna,” he said, adding he expected it would be less effective now there was no ice tongue.
A Japanese-led study published earlier this month estimated that the loss of the ice tongue led to nearly 25 percent less dense water formation.
Rintoul’s team have been taking samples in the area measuring salinity, temperature, oxygen and carbon and the results will be studied over the coming weeks.
Studying the damage to the Mertz Glacier would help efforts to project future changes in climate, he said.
“It allows us to explore how sensitive the formation of that dense water is to things like the shape of the continent and change in the effectiveness in these polynas,” he said.
As the oceans heated up, warmer water would likely increase the rate these floating tongues of ice melted, he said, exposing glaciers on the continent to warmer seas. This risked faster rates of melting and discharge of ice into the ocean, raising sea levels.
Canada’s pristine western coastline could be endangered by a plan to build a new oil pipeline from Alberta to the coast in order to export oil overseas, say environmental activists and native people who rely on these waters.
Oil company Enbridge plans to link the oil sands of Athabasca, in central Alberta, to the port town of Kitimat in British Columbia, with a new pipeline that would carry 525,000 barrels of oil to the coast per day.
There’s just one problem: the pipeline would pass through watersheds important to Canada’s commercial fishing industry and brush past Coastal First Nations lands and the Great Bear Rainforest, a protected coastal area filled with red cedars, spruce, and the elusive all-white “spirit bear.”
While the Northern Gateway pipeline itself wouldn’t pass through the 4.4-million-acre (1.8-million-hectare) Great Bear Rainforest, activists say it’s a little too close for comfort. The International League of Conservation Photographers recently performed a Rapid Assessment Visual Expedition (RAVE) in the area, sending a dozen photographers to the rain forest to document the ecosystem they believe is at risk. A pipeline means more tankers, and because the Kitimat terminal is separated from the open ocean by more than one hundred miles of channels and fjords, the photographers argue that a tanker spill would imperil the local environment. “These are highly treacherous waters, with tremendous currents,” said Cristina Mittermeier, ILCP president.
The danger is not just to plants and wildlife: The lifestyle of the First Nations people living in and around the rain forest, such as these Gitga’at fishermen gathering crab in a photo from the Great Bear RAVE, would be at risk. “One major oil spill on the coast of British Columbia would wipe us out,” Coastal First Nations director Gerald Amos said in a statement.
In recent decades documented biological changes in the far Northern Hemisphere have been attributed to global warming, changes from species extinctions to shifting geographic ranges. Such changes were expected because warming has been fastest in the northern temperate zone and the Arctic.
But new research published in the Oct. 7 edition of Nature adds to growing evidence that, even though the temperature increase has been smaller in the tropics, the impact of warming on life could be much greater there than in colder climates.
The study focused on ectothermic, or cold-blooded, organisms (those whose body temperature approximates the temperature of their surroundings). Researchers used nearly 500 million temperature readings from more than 3,000 stations around the world to chart temperature increases from 1961 through 2009, then examined the effect of those increases on metabolism.
“The expectation was that physiological changes would also be greatest in the north temperate-Arctic region, but when we ran the numbers that expectation was flipped on its head,” said lead author Michael Dillon, an assistant professor of zoology and physiology at the University of Wyoming.
Freshwater is flowing into Earth’s oceans in greater amounts every year, a team of researchers has found, thanks to more frequent and extreme storms linked to global warming. All told, 18 percent more water fed into the world’s oceans from rivers and melting polar ice sheets in 2006 than in 1994, with an average annual rise of 1.5 percent.
“That might not sound like much — 1.5 percent a year — but after a few decades, it’s huge,” said Jay Famiglietti, UC Irvine Earth system science professor and principal investigator on the study, which will be published this week in Proceedings of the National Academy of Sciences. He noted that while freshwater is essential to humans and ecosystems, the rain is falling in all the wrong places, for all the wrong reasons.
“In general, more water is good,” Famiglietti said. “But here’s the problem: Not everybody is getting more rainfall, and those who are may not need it. What we’re seeing is exactly what the Intergovernmental Panel on Climate Change predicted — that precipitation is increasing in the tropics and the Arctic Circle with heavier, more punishing storms. Meanwhile, hundreds of millions of people live in semiarid regions, and those are drying up.”
A global analysis of extinction risk for the world’s plants, conducted by the Royal Botanic Gardens, Kew together with the Natural History Museum, London and the International Union for the Conservation of Nature (IUCN), has revealed that the world’s plants are as threatened as mammals, with one in five of the world’s plant species threatened with extinction.
The study is a major baseline for plant conservation and is the first time that the true extent of the threat to the world’s estimated 380,000 plant species is known, announced as governments are to meet in Nagoya, Japan in mid-October 2010 to set new targets at the United Nations Biodiversity Summit.