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TOPIC: Ancient climate


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RE: Ancient climate
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Hothouse climates of the past - lessons for the future

Some of the world's leading climate change scientists will be in Bristol next week to discuss extreme warm climates throughout the history of the earth and how they help us understand the future of our planet.
The workshop on May 22 and 23 will be hosted by the University of Bristol's Cabot Institute which carries out fundamental and responsive research on risks and uncertainties in a changing environment.

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Ice cave in Transylvania yields window into region's past

Ice cores drilled from a glacier in a cave in Transylvania offer new evidence of how Europe's winter weather and climate patterns fluctuated during the last 10,000 years, known as the Holocene period.
The cores provide insights into how the region's climate has changed over time. The researchers' results, published this week in the journal Scientific Reports, could help reveal how the climate of the North Atlantic region, which includes the U.S., varies on long time scales.

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Uranium levels in deep sea coral reveal new insights into how the major northern ice sheets retreated

Scientists examining naturally occurring uranium levels in ancient deep sea corals have discovered new insights into how the major northern ice sheets retreated during the last major deglaciation on Earth.
When continental rocks are eroded they bring trace amount of uranium into the ocean. The 234U daughter isotope is more mobile than its parent 238U, so weathering has led to an ocean that has a 15 percent excess of 234U when compared to 238U.
The team looked at 234U/238U reconstructions of the last 50,000 years based on the exceptionally well-preserved deep-sea corals from the equatorial North Atlantic and Pacific Galapagos platform.
Their results reveal a detailed record of 234U/238U in the oceans which provide new insights into how the major northern ice sheets retreated during the last major deglaciation on Earth (about 18,000 to 11,000 years ago).

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Plankton Reveal New Secrets About Ancient CO2 Levels

Scientists studying past global temperatures and carbon dioxide (CO2) levels have struggled to explain a global cooling that occurred between 11 and 6 million years ago.
Generally, such drops correspond with plummeting CO2, but previous measurements have found only a modest decrease in the greenhouse gas during the period. New research, however, has revealed a CO2 plunge that scientists have never before detected, and the clue lies in tiny ocean plankton.

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Paleo-Climate
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RSMAS Scientist Develops Model for Paleo-Climate Study

A study by an international team of scientists uncovered new information about marine plankton, the tiny, globetrotting organisms commonly used to reconstruct past climate conditions. The findings can aid in improving our understanding of past global climate conditions.
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Reconstruction of Earth climate history shows significance of recent temperature rise

Using data from 73 sites around the world, scientists have been able to reconstruct Earth's temperature history back to the end of the last Ice Age, revealing that the planet today is warmer than it has been during 70 to 80 percent of the time over the last 11,300 years.
Of even more concern are projections of global temperature for the year 2100, when virtually every climate model evaluated by the Intergovernmental Panel on Climate Change (IPCC) shows that temperatures will exceed the warmest temperatures during that 11,300-year period known as the Holocene - under all plausible greenhouse gas emission scenarios.
 
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Jurassic records warn of risk to marine life from global warming

The risk posed by global warming and rising ocean temperatures to the future health of the worlds marine ecosystem has been highlighted by scientists studying fossil records.
Researchers at Plymouth University believe that findings from fieldwork along the North Yorkshire coast reveal strong parallels between the Early Jurassic era of 180 million years ago and current climate predictions over the next century.
 
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Volcano location could be greenhouse-icehouse key

A new Rice University-led study finds the real estate mantra "location, location, location" may also explain one of Earth's enduring climate mysteries. The study suggests that Earth's repeated flip-flopping between greenhouse and icehouse states over the past 500 million years may have been driven by the episodic flare-up of volcanoes at key locations where enormous amounts of carbon dioxide are poised for release into the atmosphere.
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Stalagmite climate record
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Cave clue to 13,000 winters

Over 13,000 years ago a stalagmite began to grow in a cave in Oregon.
Each winter rainwater from the land above made its way through the cave's ceiling and dripped onto the floor. As each layer of the stalagmite formed, oxygen and carbon isotopes within these raindrops were captured and preserved inside the rock.
Now, thousands of years later, a team led by Oxford University scientists is using the data locked inside this stalagmite to get a glimpse of the ancient winter climate of Western North America.

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Ancient Alteration of Seawater Chemistry Linked With Past Climate Change

Scientists have discovered a potential cause of Earth's "icehouse climate" cooling trend of the past 45 million years. It has everything to do with the chemistry of the world's oceans.
The dissolution or creation of massive gypsum deposits changes the sulphate content of the ocean, say the scientists, affecting the amount of sulphate aerosols in the atmosphere and thus climate.

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