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Climate: Genetic study takes nuanced look at historic penguin response to global warming

Gradual warmup after ice age was beneficial to many species, but rapid rate of current warming may be too much for the flightless birds

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Populations of chinstrap penguins are declining fast as sea ice melts around the Antarctic Peninsula. bberwyn photo.

By Summit Voice

* More Summit Voice stories and photos on penguins here.

FRISCO — A new genetic analysis of historic penguin populations in Antarctica offers a nuanced view of how the flightless birds responded to climate change during the past 30 years. The findings suggests that, between the last ice age and up to around 1,000 years ago, penguin populations expanded as ice retreated and global temperatures warmed.

But warming has accelerated the past few decades; now many species may be declining because ice is retreating too far and too fast, according to the researchers from the Universities of Southampton and Oxford, who looked at genetic diversity to recreate past population sizes. A report of the research is published in the journal Scientific Reports. Continue reading

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Climate: Icebergs scouring biodiversity from sea-bottom boulders around the Antarctic Peninsula

‘The Antarctic Peninsula can be considered an early warning system … ‘

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Icebergs near the shore of the Antarctic Peninsula are scouring the sea-bottom of its biodiversity, according to researchers with the British Antarctic Survey. bberwyn photo.

Staff Report

FRISCO — Antarctic icebergs set free to roam near the shore by global warming are fundamentally changing the seafloor ecology, according to researchers with the British Antarctic Survey.

Boulders on the shallow seabed — once encrusted with a rich assemblage of species in intense competition for limited space — now mostly support a single species. The climate-linked increase in iceberg activity has left all other species so rare as to be almost irrelevant, according to the new study published in the Cell Press journal Current Biology on June 16.

“The Antarctic Peninsula can be considered an early warning system—like a canary in a coal mine,” says David Barnes of the British Antarctic Survey. “Physical changes there are amongst the most extreme and the biology considered quite sensitive, so it was always likely to be a good place to observe impacts of climate change—but impacts elsewhere are likely to be not too far behind. A lot of the planet depends on the near-shore environment, not least for food; what happens there to make it less stable is important.” Continue reading

Climate: Arctic sea ice third-lowest on record for May

Antarctic sea ice at record high; northern hemisphere snow cover shows rapid spring decline

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Low spring snow cover in the northern hemisphere.

Staff Report

FRISCO — Arctic sea ice extent in May was about a quarter of a million square miles below the 1981-2010 average, ending up as the third-lowest on record for the month, according to the latest update from the National Snow and Ice Data Center.

By contrast, sea ice extent around Antarctica is at a record high, almost half a million square miles above the 1981-2010 baseline, marking the highest May Antarctic sea ice extent on record. Read the full NSIDC report here. Continue reading

Report shows global warming threats to Mediterranean

‘We all need to act and there is no time to lose’

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The Ionian Sea near Ksamil, Albania. bberwyn photo.

Staff Report

FRISCO — There’s no reason to believe that any of the world’s oceans will be spared the effects of global warming and ocean acidification, including the Mediterranean Sea, where rapid changes threaten numerous species and entire ecosystems, according to a new report from a team of European researchers.

“We knew next to nothing about the combined effects of warming and acidification in the Mediterranean until this study, now we know that they are a serious double threat to our marine ecosystems,” said project coordinator Patrizia Ziveri, from Institute of Environmental Science and Technology at the Universitat Autonoma de Barcelona. Continue reading

Climate: More wine, less maple syrup in Vermont

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Vermont’s average temperature will increase by more than five degrees Fahrenheit by 2100.

State assessment drills into global models to help planners prepare for climate change

By Summit Voice

FRISCO — State and federal climate experts say Vermont will see big changes as global temperatures warm in the next half century. The state’s ski industry may enjoy a “sweet spot’ of sorts, with the possibility of increased snow for the next 25 years, but the maple syrup business may struggle.

Vermont this week released a state-based climate assessment, scaling down global climate models and using local knowledge to try and get a solid handle on how the changes will play out in the Green Mountain State. Risks include an 80 percent change of increased flooding, as well as better odds for short-term droughts — extreme weather, in other words. Continue reading

Climate: Forest growing season expands

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Some forests in the U.S. are greening up earlier than ever in a warming world. bberwyn photo.

Detailed Harvard research tracks changes in eastern forests

Staff Report

FRISCO — Forests in the eastern U.S. are greening up earlier than ever and staying green longer at the end of the growing season, Harvard scientists conclude in a new study.

Thanks to the extended growing season, the trees are storing more carbon dioxide, but there’s no guarantee that beneficial side effect will persist into the future, the researchers said, explaining that changing precipitation patterns could disrupt forests in other ways. Continue reading

Iron a key link in ocean-climate system

‘If warming climates lower iron levels at the sea surface, as occurred in the past, this is bad news for the environment’

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The link between iron concentrations in the ocean and global temperatures may result in a feedback loop leading to yet more warming, a new study says.

FRISCO — Scientists with the University of Edinburgh say they may have pinpointed the granddaddy of all climate feedback mechanisms, saying that rising global temperatures could indirectly increase the amount of greenhouse gases released from the world’s oceans.

After studying the abundance of silicon and iron from the fossils of plankton  in a 26,000-year-old core sediment from the Gulf of California, the researchers found that, those periods when silicon was least abundant in ocean waters corresponded with relatively warm climates, low levels of atmospheric iron, and reduced CO2 uptake by the oceans’ plankton. Continue reading

Study shows flurry of threats to rainforests

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Tree canopy studies show rapid changes in Amazon rainforest. Photo courtesy NASA/JPL-Caltech.

Is global warming the knockout punch?

Staff Report

FRISCO — After watching Amazon forests change for decades, a team of researchers say the region is under the gun from multiple threats that threaten to deliver a knockout punch.

The 35-year study focused on how diverse communities of trees and vines respond when the Amazonian rainforest is fragmented by cattle ranching. Continue reading

Climate: Current rate of ocean acidification is 10 times faster than during ancient warming period

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Ocean researchers say increasingly acidified water is eating away at the shells of tiny sea snails. Photo courtesy NOAA.

“The real unknown is how individual organisms will respond and how that cascades through ecosystems”

By Staff Report

FRISCO — The surge of carbon dioxide released by humankind’s use of fossil fuels may overwhelm the world’s oceans with an unprecedented rate of acidification, scientists said this week as they released a study showing historic rates of acidification.

Specifically, the researchers looked at pulse of CO2 that happened about 56 million years ago, when global temperatures soared and carbon sediments in the oceans simply dissolved, while some marine organisms went extinct. They traced the rate of acidification during that era by analyzing fossil chemistry, finding that ocean acidity may have increased by a 100 percent in just a few thousand years — and today’s rate is even higher.

Publishing the results of their study in the journal Paleoceanography, the scientists explained that the sudden increase kept acidity levels high for about 70,000 years and radically changed the ocean environment.
Continue reading

Study tracks historic Antarctica meltdowns

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Reading the history of Antarctica’s ice sheets is helping climate scientists project the future.

Transition from glacial periods punctuated by sudden surges of ice melt and sea level rise

Staff Report

FRISCO — Even without the addition of heat-trapping greenhouse gases from fossil fuel combustion, the Antarctica ice sheets may be vulnerable to sudden collapse and melting. One such episode, about 14,600 years ago, is thought to have caused sea level to rise by more than 12 feet in just 100 years.

Scientists are racing to understand the dynamics of the Antarctic ice sheets because of the potentially significant consequences of rapid changes, and in one of the newest studies, they’ve traced some of the big iceberg calving events between about 19,000 and 9,000 years ago by analyzing deep sea sediment cores extracted from the region between the Falkland Islands and the Antarctic Peninsula. Continue reading

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