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Crown Capital Management Jakarta Indonesia - The Company-Squidoo
Crown Capital Management Jakarta Indonesia - The Company-Squidoo
Crown Capital Eco Management works with government bodies, international entities, private sectors and other non-governmental organizations in providing extensive information to the public
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When ice sheets marched across North America 20,000 years ago during the Last Glacial Maximum, they devoured liveable areas for caribou and isolated them from their Eurasian relatives for thousands of years.
Now researchers have evidence that such climatic events have sculpted the genetics of North American caribou, which may make the animals unable to adapt to future climate change.
“Although the past is not a guarantee for the future, it makes me pessimistic about the future of the species,” says Glenn Yannic, a population geneticist at Laval University in Quebec City, Canada, and lead author of a study published today in Nature Climate Change1.
Major caribou herds around the globe are in decline. Scientists have blamed this on natural resource development and new roads that encroach on caribou habitat, and on changes in climate that put migrating caribou out of sync with spring plant growth, leaving them hungry. Most studies that forecast climate impacts on species look at ecosystems, individual species or populations, but not genetic factors on a global scale, says Yannic.
“We’ve already been through a lot of climate change,” says Paul Wilson, a conservation geneticist at Trent University in Peterborough, Canada. “The genetics will give us information on what happened at the ice-age interface, so why wouldn’t you use it to then make projections?”
Genetic analysis
Yannic and his colleagues charted caribou evolution by analysing short lengths of DNA, called markers, from 1,297 caribou in the species' current range.
The analysis revealed two distinct lineages of caribou that diverged about 300,000 years ago. The Euro-Beringia group currently ranges from Eurasia to western North America, occupying Greenland, Norway’s Svalbard archipelago, Russia, Alaska and the Canadian Arctic archipelago. The North American lineage settled in Quebec, Newfoundland and the Canadian Prairies.
The work also showed differences in the genetic richness, or diversity, of the two groups. The researchers focused their genetic analysis on DNA sequences that are not known to help caribou adapt to new environments — known as neutral markers.
They then paired the genetic data with a climate model that produced maps of suitable caribou habitat every 1,000 years for the past 21,000 years. This allowed them to hindcast the distribution of the two caribou lineages through time; they found the distribution of the groups lined up in both models. “It means we can be confident that climate has had a big influence on the distribution of caribou,” says Yannic.
Only a thin stretch of habitat remained suitable for caribou in North America 21,000 years ago during the glaciation, killing off much of the population. As a result, many gene variants disappeared completely and the genetic diversity of the North American caribou lineage diminished. By contrast, the Euro-Beringia caribou, living in a more stable climate during the same period, were more genetically diverse.
Future shock
The team then looked to the future. If greenhouse-gas emissions remain stable, their model indicates that North American caribou may lose as much as 89% of their suitable habitat by 2080. Coupled with lower levels of genetic diversity, this could make North American caribou a rare sight outside of northern Quebec and Labrador, Yannic says.
He predicts that the Euro-Beringia group will not suffer as badly, even though it may lose up to 60% of its suitable habitat.
“It’s heartening to know that they are predicting some stability in the Eurasian population,” says Tara Fulton, a palaeogeneticist at the University of Alberta in Edmonton, Canada. “If the caribou have lots of diversity in these neutral markers, they will probably have a lot of diversity in those genes that allow them to adapt to environmental change.”
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Climate change may be far worse than scientists thought, causing global temperatures to rise by at least 4 degrees Celsius by 2100, or about 7.2 degrees Fahrenheit, according to a new study.
The study, published in the journal Nature, takes a fresh look at clouds' effect on the planet, according to a report by The Guardian. The research found that as the planet heats, fewer sunlight-reflecting clouds form, causing temperatures to rise further in an upward spiral.
That number is double what many governments agree is the threshold for dangerous warming. Aside from dramatic environmental shifts like melting sea ice, many of the ills of the modern world -- starvation, poverty, war and disease -- are likely to get worse as the planet warms.
"4C would likely be catastrophic rather than simply dangerous," lead researcher Steven Sherwood told the Guardian. "For example, it would make life difficult, if not impossible, in much of the tropics, and would guarantee the eventual melting of the Greenland ice sheet and some of the Antarctic ice sheet."
Another report released earlier this month said the abrupt changes caused by rapid warming should be cause for concern, as many of climate change's biggest threats are those we aren't ready for.
In September, the Intergovernmental Panel on Climate Change said it was "extremely likely" that human activity was the dominant cause of global warming, or about 95 percent certain -- often the gold standard in scientific accuracy.
"If this isn't an alarm bell, then I don't know what one is. If ever there were an issue that demanded greater cooperation, partnership, and committed diplomacy, this is it," U.S. Secretary of State John Kerry said after the IPCC report was released.
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HERE'S some news to put a great big smile on your face: apparently, Arctic sea ice volume is up by 50 per cent. Have you cracked open the champagne yet? Did you ring all your mates? Me neither. In fact, to be honest, I couldn't care less whether it's up 50 per cent or down 50 per cent. It's just weather doing what weather does - changing all the time. But you wouldn't guess this from the way it is reported in the media. Sceptical websites are presenting it as a vindication of their longstanding claim that all the fuss about catastrophic, man-made global warming has been greatly overdone. Warmist news outlets ("a rare piece of good news", declared the BBC) are greeting it as a sign of hope that maybe there is time left for us to save the planet from the Greatest Threat It Has Ever Known.
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