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- 9 March 2009 at 3:24 pm #4590
From Sci American:Quote:The shells of tiny ocean animals known as foraminifera—specifically Globigerina bulloides—are shrinking as a result of the slowly acidifying waters of the Southern Ocean near Antarctica. The reason behind the rising acidity: Higher carbon dioxide (CO2) levels in the atmosphere, making these shells more proof that climate change is making life tougher for the seas’ shell-builders.
The researchers found that modern G. bulloides could not build shells as large as the ones their ancestors formed as recently as century ago. In fact, modern shells were 35 percent smaller than in the relatively recent past—an average of 17.4 micrograms compared with 26.8 micrograms before industrialization.5 September 2009 at 4:46 am #4640
Grim report in the Guardian includes:Quote:Coral reefs are doomed. The situation is virtually hopeless. Forget ice caps and rising sea levels: the tropical coral reef looks like it will enter the history books as the first major ecosystem wiped out by our love of cheap energy.
Today, a report from the Australian government agency that looks after the nation’s emblematic Great Barrier Reef reported that "the overall outlook for the reef is poor and catastrophic damage to the ecosystem may not be averted". The Great Barrier Reef is in trouble, and it is not the only one.
Within just a few decades, experts are warning, the tropical reefs strung around the middle of our planet like a jewelled corset will reduce to rubble. Giant piles of slime-covered rubbish will litter the sea bed and spell in large distressing letters for the rest of foreseeable time: Humans Were Here.
"The future is horrific," says Charlie Veron, an Australian marine biologist who is widely regarded as the world’s foremost expert on coral reefs. "There is no hope of reefs surviving to even mid-century in any form that we now recognise. If, and when, they go, they will take with them about one-third of the world’s marine biodiversity. Then there is a domino effect, as reefs fail so will other ecosystems. This is the path of a mass extinction event, when most life, especially tropical marine life, goes extinct."
Alex Rogers, a coral expert with the Zoological Society of London, talks of an "absolute guarantee of their annihilation". And David Obura, another coral heavyweight and head of CORDIO East Africa, a research group in Kenya, is equally pessimistic: "I don’t think reefs have much of a chance. And what’s happening to reefs is a parable of what is going to happen to everything else."11 September 2009 at 7:33 am #4645Quote:"The Arctic as we know it may soon be a thing of the past," says Eric Post, associate professor of biology at Penn State University. Post leads a large, international team that carried out ecosystem-wide studies of the biological response to Arctic warming during the fourth International Polar Year, which ended in 2008.
"Species on land and at sea are suffering adverse consequences of human behavior at latitudes thousands of miles away," declares Post. "It seems no matter where you look — on the ground, in the air, or in the water — we’re seeing signs of rapid change."
The study led by Post shows that many iconic Arctic species that are dependent upon the stability and persistence of sea ice are faring especially badly. Loss of polar ice habitat is causing a rapid decline in the numbers of ivory gull, Pacific walrus, ringed seal, hooded seal, narwhal, and polar bear. The researchers found that Polar bears and ringed seals, both of which give birth in lairs or caves under the snow, lose many newborn pups when the lairs collapse in unusually early spring rains. These species may be headed for extinction.
The research also reveals that species once confined to more southerly ranges now are moving northward. Among the most visible invaders are red foxes, which are displacing Arctic foxes from territories once too cold for red foxes. Some of the less showy invaders that the scientists found also are moving northward include the winter moth, which defoliates mountain birch forests, and species of Low Arctic trees and shrubs, which affect the dynamics of trace-gas exchange. The presence of more shrubs and trees promotes deeper snow accumulation, increasing soil temperatures during the winter, and more microbial activity in the soil, which in turn makes the habitats more suitable for shrubs.14 February 2010 at 2:32 pm #4680
From press release for Centre for Ecology and Hydrology:Quote:The recent trend towards earlier UK springs and summers has been accelerating, according to a study published today (9 February 2010) in the scientific journal Global Change Biology.
The collaborative study, involving scientists from 12 UK research institutions, universities and conservation organisations, is the most comprehensive and rigorous assessment so far of long-term changes in the seasonal timing (phenology) of biological events across marine, freshwater and terrestrial environments in the UK.
Led by Dr Stephen Thackeray and Professor Sarah Wanless of the Centre for Ecology & Hydrology, the research gathers together more than 25,000 long-term phenology trends for 726 species of plants and animals. More than 80% of trends between 1976 and 2005 indicate earlier seasonal events. The study considers a diverse array of organisms including plankton, plants, insects, amphibians, fish, birds and mammals. On average, the seasonal timing of reproduction and population growth has become earlier by more than 11 days over the whole period, but change has accelerated in recent decades.
The research shows that there are large differences between species in the rate at which seasonal events have shifted. Changes have been most rapid for many organisms at the bottom of food chains, such as plants and the animals that feed upon them. Predators have shown slower overall changes in the seasonal timing of their life cycle events. However, the seasonal timing of reproduction is often matched to the time of year when food supply increases, so that offspring receive enough food to survive.
A key question is whether animals higher up the food chain will react to the faster rates of change in the plants and animals they feed upon, or whether they will fail to do so and become less successful at rearing their offspring.19 March 2010 at 5:13 pm #4688
From University of Melbourne press release:Quote:Butterflies are emerging in spring over 10 days earlier than they did 65 years ago, a shift that has been linked to regional human-induced climate change in a University of Melbourne- led study. The work reveals for the first time, a causal link between increasing greenhouse gases, regional warming and the change in timing of a natural event.
The study found that over a 65 year period, the mean emergence date for adults of the Common Brown butterfly (Heteronympha merope) has shifted 1.6 days earlier per decade in Melbourne, Australia. The findings are unique because the early emergence is causally linked with a simultaneous increase in air temperatures around Melbourne of approximately 0.14°C per decade, and this warming is shown to be human-induced (anthropogenic).20 March 2010 at 2:57 am #4689
Guest commentary on RealClimate by Simon Lewis, a rainforest experts, rebuts claims a recent paper indicates the Amazon rainforest can withstand droughts, and hence won't be real affected by global warming.
[Stands to reason, really, that a rainforest needs, err, rain and plenty of it – but reason is not something Fox News n co are too bothered about.]
Includes:Quote:Rainforest persists above a threshold of rainfall, below which one finds savanna. If this threshold is crossed a landscape dominated by rainforest can ‘flip’ to savanna. Therefore a ’slight’ reduction can lead to a ‘dramatic’ reaction. Of course, evidence of a shift to a new lower rainfall climate regime is needed, and evidence of large areas of forest close to that rainfall threshold would be required for the IPCC statement to be reasonable; there is ample published evidence for both.
Overall the conclusions in the IPCC 2007 Fourth Assessment Report are strengthened (because the anomalous result of the Saleska et al. 2007 paper appear to be at fault), not weakened, by the new Samanta et al. study as their press release implies.15 May 2010 at 9:06 am #4707
From Washington Post:Quote:an international team of biologists reports that in more than one-tenth of the places in Mexico where lizards flourished in 1975, the reptiles now cannot be found. The researchers predict that by 2080, about 40 percent of local lizard populations worldwide will have died off and 20 percent of lizard species will be extinct.
The reason for the huge die-off appears to be rising temperatures. But it isn't heat that is killing the lizards directly.
Instead, global warming appears to be lengthening the period of the day when lizards must seek shelter or risk fatal overheating. In the breeding season, that sheltering period is now so long that females of many species are unable to eat enough food to produce eggs and offspring.
Springs that start earlier and are warmer than they once were have been noted in many regions of the world in the past three decades. The new study suggests that the phenomenon may be far more important for the survival of some animals than peak summer temperatures, said Barry Sinervo, an evolutionary biologist at the University of California at Santa Cruz who headed the 26-person research team.
"It is as if something has really happened in world climate and the lizards are telling us that," he said.
The lizard findings also suggest that early stages of global warming may be more than a warning: They may have permanent consequences.
"Many of us have been worried about extinctions in the future," said Raymond B. Huey, a lizard physiologist at the University of Washington in Seattle, who wrote a commentary accompanying the study. "This paper shows that extinctions are already here. I think that will really be surprising to most biologists."24 May 2010 at 10:31 am #4715
News from Nature adds to evidence global warming is a threat to biodiversity:Quote:
The period of global warming linked to the extinction of animal giants such as the woolly mammoth also made its mark on smaller mammals who survived the event.
Adaptable deer mice came to dominate the small furry communities of northern California as the climate warmed at the end of the last ice age, around 11,700 years ago, an excavation of one ancient woodrat nest shows. Overall, the number of small mammalian species in the area declined by about one-third, say Jessica Blois, currently at the University of Wisconsin, Madison, and her colleagues.
The study, published today in Nature1, emphasizes that concentrating solely on eye-catching species extinctions fails to capture the full impact of climate change on biodiversity. "If we focus only on extinction, we're not getting the whole story," says Blois. The work also suggests that rapidly reproducing, adaptable species — such as the deer mice — could benefit further from future warming.
Past climate change led to lower diversity in the small and furry.22 September 2010 at 2:22 am #4734Anonymous
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