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Climate: New clues for ancient Great Basin lakes

Nevada’s Walker Lake is a remnant of one of the great inland lakes that covered parts of the Great Basin during the last glacial cooling period. Image courtesy NASA Earth Observatory.

Glacial climate regime may have enhanced Southwest Monsoon

By Summit Voice

SUMMIT COUNTY — Geologists and paleoclimatologists have long known that the great basins of the intermountain West were once filled with water, forming vast inland seas. At the peak of the last glacial cooling period, about 14,000 to 20,000 years ago as much as a quarter of Nevada and Utah were covered with water.

What’s not exactly clear is where and when the water came from, but a new study led by a Texas A&M researcher offers additional clues, suggesting that the additional moisture came from a powerful, enhanced summer monsoon.

First, the scientists set out to test the prevailing hypothesis that the water resulted from a shift in the winter storm track that now generally carries storm to the north of the Great Basin, into northern California, Washington and Oregon. Continue reading

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Global warming: New climate clues from Antarctica

Study shows how high latitudes may change with increased CO2 levels

Increasing concentrations of CO2 could turn this Antarctic beach into a tropical zone. Photo by Bob Berwyn.

By Summit Voice

SUMMIT COUNTY — If the past is any indication of the future, tropical plants could one day again thrive in Antarctica, just as they did about 52 million years ago during an intense warming phase when global atmospheric carbon dioxide levels were about twice as high as they are today.

New test drilling by German researchers shows that palms and relatives of tropical baobab trees grew along the coast of Antarctica, with the interior dominated by temperate rainforests characterized by southern beech and Araucaria trees of the type common in New Zealand today.

The research, published in the journal Nature, helps illustrate  the relationship between climate change, variations in atmospheric carbon dioxide and the reaction of Earth’s biosphere. The results highlight the extreme contrast between modern and past climatic conditions on Antarctica and the extent of global warmth during periods of elevated atmospheric carbon dioxide levels. Continue reading

Antarctic current seen as key player in global climate

The Antarctic Circumpolar Current prevents warmer water from reaching Antarctica and links the Atlantic, Pacific and Indian Ocean basins.

Major global climate change from tropical Eocene conditions to cooler, modern climate linked to formation of the Antarctic Circumpolar Current

By Summit Voice

SUMMIT COUNTY — In trying to understand current global climate changes, researchers often reach far back into the planet’s history to try and understand what caused past shifts.

One of the most significant global changes came when early Cenozoic “greenhouse” climates shifted to the mid- to late Cenozoic ‘icehouse’ that saw repeated massive glaciations of the polar regions, said Candace Major, program director in the National Science Foundation’s Division of Ocean Sciences.

Before that shift, some 38 million years ago, tropical jungles thrived in what are now the cornfields of the American Midwest and furry marsupials wandered temperate forests in what is now the frozen Antarctic. During that era —  the late Eocene, the temperature differences between the equator and Antarctica were only half what they are today. Continue reading

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