The Hot Zone

Gray whales a model in climate adaptation

In the time since California gray whales existed, the Earth has gone through more than 40 cycles of warming and cooling. Many species have been impacted and have even died out, but the gray whale has persisted for 250 million years. How did the gray whale survive? The gray whales, it turns out, may be a model in how a species can adapt and change during dramatic swings in the Earth’s climate. In the modern era, whaling has been the biggest threat to the gray whale survival, and in fact the... [Read more]

Posted by Alison Hawkes on July 14, 2011 1 Comment »
Category : Climates of the Past

Past warming one-tenth rate of modern day climate change

Climate scientists find it useful to use analogs to put modern day change into historical perspective. No analog is more useful than the Palaeocene–Eocene Thermal Maximum, a period of rapid warming that occurred 56 million years ago when the continents were virtually in the same location as today. During the PETM, temperatures shot up 9 to 16 degrees Fahrenheit over a period of 20,000 years, a result of a massive release of carbon into the ocean and atmosphere. A new study out of Penn State... [Read more]

Posted by Alison Hawkes on June 6, 2011 No Comments »
Category : Climates of the Past

Rapid increases in greenhouse gases part of Earth’s history

Rapid increases in greenhouse gases have happened more frequently in the Earth’s history than previously realized, according to a Scripps Institution of Oceanography-led study published last week in the journal Nature. Scientists have studied extensively the the Palaeocene-Eocene Thermal Maximum (PETM), about 56 million years ago, a period of rapid global warming that’s associated with a temperature spike on par with expectations for today’s global warming scenarios. But according... [Read more]

Posted by Alison Hawkes on March 23, 2011 No Comments »
Category : Climates of the Past

Antarctic ice sheet may be more durable than thought

The stability of Antarctic ice has long concerned climate scientists. If the west Antarctic ice sheet’s base were to collapse, global sea levels could shoot up by five meters. But new research shows the ice could be a bit more tough than scientists thought. In a study published online last month in the geo-science journal Palaeogeograpy, Palaeoclimtology, Palaeoecology, University of Exeter-led geographer Christopher Fogwill and colleagues found that blue-ice moraines in West Antarctica fluctuated... [Read more]

Posted by Alison Hawkes on March 7, 2011 No Comments »
Category : Climates of the Past

Sixth extinction almost here, but not quite

Scientists define a mass extinction as when the Earth loses more than 75 percent of its species in short geological time, within 2 million years. This hasn’t happened very often — only five times in the last 540 million years. Is it happening now again? The “sixth extinction” has been discussed by biologists for decades. In a paper published this week in the journal Nature, University of California at Berkeley-led biologists take stock on the status of the the Earth’s... [Read more]

Posted by Alison Hawkes on March 3, 2011 No Comments »
Category : Climates of the Past, The man made climate

Climate change could signal prolonged droughts in American Southwest

Think the 1930s “Dust Bowl” was bad in the American West? Scientists have found evidence of “mega-drought” events that lasted centuries to millennia in the same region during warm, interglacial periods in the Pleistocene era (370,000-550,000 years ago). The evidence heightens concern over how the region will react to the modern day global temperature spikes. A dust storm in Oklahoma, 1936. Photo: Arthur Rothstein The American Southwest is already predicted to get pretty dry... [Read more]

Posted by Alison Hawkes on February 25, 2011 1 Comment »
Category : Climates of the Past

Coal ash cause of Permian extinction

The mass Permian extinction 250 million years ago is frequently blamed on volcanoes. But a new study shows that what may have really tipped the climate was the volcanic release of massive amounts of combusted coal –  similar to modern day coal ash from coal-fired power plants. If so, modern day climate change hasn’t been the first time that burning coal was to blame. The extinction of that era wiped out some 90 percent of marine species, one of the largest extinction events in history.... [Read more]

Posted by Alison Hawkes on January 28, 2011 1 Comment »
Category : Climates of the Past

Earth’s sensitivity to CO2 may be twice what climate models show

Climate modeling is an inexact science, and scientists have long known that the models don’t account for everything, even though precision and accuracy is a big goal. But the limitations of climate modeling may have caused scientists to underestimate the Earth’s sensitivity to CO2 by a factor of two, according to an analysis by National Center for Atmospheric Research scientist Jeffrey Kiehl. In a perspectives piece published in the journal Science this week, Kiehl says that the models... [Read more]

Posted by Alison Hawkes on January 14, 2011 No Comments »
Category : Climate Science and Scientists, Climates of the Past

Invasive species can trigger mass extinction

Invasive species are becoming more rampant today as a result of climate change and other factors. Changes in precipitation and temperature patterns often favor invasives, which have an uncanny ability to adapt and spread in stressed ecosystems. A new study shows how invasives can actually trigger a mass extinction similar, perhaps, to what we’re seeing under modern day biodiversity loss. Geologist Alycia Stigall at Ohio University explored the late Devonian extinction, one of five mass extinctions... [Read more]

Posted by Alison Hawkes on December 31, 2010 1 Comment »
Category : Climates of the Past

Changes in human culture match major climate shifts

A changing climate changes the environment. We know that. But it also may change culture. In a lesson that could have some relevance to human societies today, geographers at the University of Ottawa examined the overlap between climatic change and the changes in tool technology and other artifacts by Native American tribes during three ancient time periods. Humans have lived on the North American continent long enough to have experienced dramatic shifts in climate caused by ice sheet expansion and... [Read more]

Posted by Alison Hawkes on December 7, 2010 No Comments »
Category : Climates of the Past

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