Paleoclimate

Message from the mud: East Antarctic meltdown could cause massive sea rise

Publication: NBC News   Date: July 21, 2013   View Article

The last time concentrations of the greenhouse gas carbon dioxide were as high as they are today, big chunks of the seemingly stable East Antarctic ice sheet melted and helped raise global sea levels more than 65 feet higher than they are now, a new study suggests.

Scientists have long known that seas were higher during the Pliocene, a geological epoch that ran from 5.3 million to 2.6 million years ago. At the time, atmospheric carbon dioxide levels were similar to today’s 400 parts per million (ppm).

“Overall, it was a warmer climate than today, but similar to what we expect to reach by the end of this century,”Carys Cook, a graduate student at the Grantham Institute for Climate Change at Imperial College London and the study’s lead author, told NBC News in an email.

Global warming study suggests human causes dating back to 1800s

Publication: NBC News   Date: April 22, 2013   View Article

A long-term global cooling trend ended in the late 19th century, a reversal in temperature that cannot be explained by natural variability alone, according to a new study.

The finding stems from 2,000-year-long continental-scale temperature records inferred from tree rings, ice cores, lake sediments and other so-called proxies from around the world.

Warming fastest since dawn of civilization, study shows

Publication: NBC News   Date: March 7, 2013   View Article

Temperatures are rising faster today than they have at any point since at least the end of the last ice age, about 11,000 years ago, according to a new study.

The finding is based on a global reconstruction of temperature records inferred from ice cores, fossils in ocean sediments and other sources. While previous studies reached similar conclusions, they covered only about 2,000 years. The new reconstruction extends the global record through the Holocene, the most recent geologic epoch.

“Another way to think of it is the period where human civilization was born, created, and developed and then progressed to where we are now,” Shaun Marcott, a climate scientist at Oregon State University who led the study, told NBC News.

Cold snaps linked to plague, civil unrest

Publication: NBC News   Date: January 14, 2013   View Article

Prolonged cold snaps over the past 1,000 years in Eastern Europe coincided with plague outbreaks, civil unrest and declines in human settlement, according to a new study that also finds the region is warmer now than it has been for the past millennium.

“It is not accurate to say that whenever it is cold you have problems, that is not the case, but there is a tendency,” study leader Ulf Buntgen, a paleoclimatologist at the Swiss Federal Research Institute in Zurich, told NBC News.

Ancient “Snowball Earth” Melted Fast Due to Methane

Publication:   Date:   View Article

A massive release of methane, a potent greenhouse gas, may have triggered rapid melting of the last “snowball Earth” about 635 million years ago, a new study suggests.

Lack of Clouds Amplified Dino-Era Warming, Study Says

Publication: National Geographic News   Date: April 10, 2008   View Article

About 100 million years ago, during the age of dinosaurs, a warming spell caused cloud cover to drastically decrease, helping drive temperatures even higher, according to a new study.

Ancient Global Warming Gave Bugs the Munchies

Publication: National Geographic News   Date: February 11, 2008   View Article

A temperature spike about 55 million years ago gave bugs the munchies, according to a new study.

If modern temperatures continue to rise as anticipated in the coming years, researchers add, the planet could see a similar increase in insect damage to crops and other plants.

© 2008-2010 Collected Writings By John Roach