Posted on 12/08/2006 3:09:43 PM PST by cogitator
Global warming 55 million years ago suggests a high climate sensitivity to carbon dioxide, according to research led by Mark Pagani, associate professor of geology and geophysics at Yale and published in the December 8 issue of Science. For some years, scientists have known that a massive release of carbon into the atmosphere caused the ancient global warming event known as the Paleocene-Eocene Thermal Maximum (PETM) that began about 55 million years ago.
The geologic record shows that the resulting greenhouse effect heated the planet as a whole by about 9 F (5 C), in less than 10,000 years.
That temperature increase lasted about 170,000 years, altered the world's rainfall patterns, made the oceans acidic, affected plant and animal life in the seas and on land, and spawned the rise of our modern primate ancestors.
"The PETM is a stunning example of carbon dioxide-induced global warming and stands in contrast to critics who argue that the Earth's temperature is insensitive to increases in carbon dioxide," said Pagani. "Not only did the Earth warm by at least 9F (5C), but it did so during a time when Earth's average temperature was already 9F warmer than today."
However, what has not been clear is how much carbon was responsible for the temperature increase and where it came from. Scientists have speculated that it might have come from massive fires from burning coal and other ancient plant material, or from 'burps' of methane from the continental shelves that rapidly became atmospheric carbon dioxide.
"According to this work, if the PETM was caused by the burning of plant material then climate sensitivity to carbon dioxide is more than 4.5F (2.5C) per carbon dioxide doubling. And if methane was the culprit, then Earth's climate must be extremely sensitive to carbon dioxide - increasing, over 10F (5.6C) per carbon dioxide doubling," noted Pagani.
This finding contradicts the position held by many climate-change skeptics that the Earth's climate is resilient to such carbon dioxide emissions and suggests that Earth's temperature will rise substantially with atmospheric carbon dioxide concentrations that are expected to double around mid-century.
"The last time carbon was emitted to the atmosphere on the scale of what we are doing today, there were winners and losers," remarked Ken Caldeira, a co-author from the Carnegie Institution's Department of Global Ecology. "There was ecological devastation, but new species rose from the ashes. Our work provides even more incentive to develop the clean energy sources that can provide for economic growth and development without risking the natural world that is our endowment."
Other authors on the paper include David Archer in the Department of Geophysical Sciences, University of Chicago, and James C. Zachos in the Earth Sciences Department, University of California, Santa Cruz. Citation: Science: (December 8, 2006).
** ping **
Interesting picture/story from Newsweak 1975.
http://weblog.theviewfromthecore.com/TheBlogFromTheCore20060428Lg.jpg
Do the math.
Let's not forget global warming on Pluto.
http://www.space.com/scienceastronomy/pluto_warming_021009.html
The nut-jobs will just claim that Pluto is no longer a planet so it doesn't count...
LOL I was thinking the exact same thing. Mars is an endangered species.
Not in the same sense that it is occurring on Earth.
"Thus inferring global warming from a 3 Martian year regional trend is unwarranted. The observed regional changes in south polar ice cover are almost certainly due to a regional climate transition, not a global phenomenon, and are demonstrably unrelated to external forcing. There is a slight irony in people rushing to claim that the glacier changes on Mars are a sure sign of global warming, while not being swayed by the much more persuasive analogous phenomena here on Earth..."
"The increasing temperatures are more likely explained by two simple facts: Pluto's highly elliptical orbit significantly changes the planet's distance from the Sun during its long "year," which lasts 248 Earth years; and unlike most of the planets, Pluto's axis is nearly in line with the orbital plane, tipped 122 degrees. Earth's axis is tilted 23.5 degrees. Though Pluto was closest to the Sun in 1989, a warming trend 13 years later does not surprise David Tholen, a University of Hawaii astronomer involved in the discovery. "It takes time for materials to warm up and cool off, which is why the hottest part of the day on Earth is usually around 2 or 3 p.m. rather than local noon," Tholen said. "This warming trend on Pluto could easily last for another 13 years."
... So it's unrelated to either solar activity or the Earth's carbon cycle, the latter being a rather obvious conclusion.
Actually I'm more interested in the reasons for these overhyped erroneous conclusions of today.
LOL!!! They claim that the warming on Mars has been for three years so doesn't count. The point is that planets go through cycles of warming/cooling WITHOUT human influence. That the writer agrees that Mars has been warming for the past three years makes my point.
"The geologic record shows that the resulting greenhouse effect heated the planet as a whole by about 9 F (5 C), in less than 10,000 years."
Ten thousand years for a 5 C increase. This article says temps will rise by 4.5 C in the next 100 years.
http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/12/10/nclimate10.xml
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