August 27, 2006

Evidence of Global Warming in the Past

Scientists have found evidence that the earth once experienced an extreme heat wave lasting 50,000 to 100,000 years and the results of that heat wave, cause yet unknown, were catastrophic for huge numbers of the living beings on earth.

The ancient hot spell, which lasted 50,000 to 100,000 years, goes by the unwieldy name of Paleocene-Eocene Thermal Maximum. It was caused by a sudden - in geological terms - doubling or tripling of carbon dioxide and other greenhouse gases in the atmosphere. Climate scientists say the result was a massive increase of 10 to 12 degrees Fahrenheit - even higher near the poles - above the prevailing temperature.

"In certain regards, the PETM is very similar to what is happening right now," said Gerald Dickens, an earth scientist at Rice University in Houston. "Just like now, a huge amount of carbon rapidly entered the ocean or atmosphere. The most notable difference is the rate. Things are happening much faster now than during the PETM."

...The long-ago heat wave "shows without a doubt that if you pump a bunch of greenhouse gases into the atmosphere, the planet warms," Matthew Huber, an earth scientist at Purdue University in West Lafayette, Ind., wrote in the June 1 edition of the journal Nature.

Scientists realized the speed and extent of the prehistoric carbon explosion only recently.

A blizzard of scientific papers "reflects the community's excitement at discovering an extraordinary perturbation in biogeochemical systems that was unimaginable 10 years ago," James Zachos, an earth scientist at the University of California, Santa Cruz, declared on his Web site.

"The evidence for dramatic warming during the event is overwhelming," Dickens said. "It is witnessed in all the oceans and continents."

Although a number of new mammal species were created during that period, the earth saw the most severe extinction in 90 million years as a number of deep-sea species died. If what we are experiencing (a significantly more rapid raise in temperatures), then we better get serious about doing something about it now.

Tom Toles tells us one thing we can do to do something about it now. (h/t to dKossian besieged by bush)

Posted by Mary at August 27, 2006 06:00 PM | Environment | Technorati links |

Don't freak out over global warming just yet.

1) The article cited metions it will take us until 2300 at current levels of greenhouse gas production to equal what the scientists think happened 55,000,000 years ago. Human population will probably peak before 2200, and then swiftly decline, so it is by no means certain we will achieve that level of greenhouse gas emissions by 2300.

2) Our ice age climate has been determined for the past 3,000,000 years by the isthmus of Panama, and our most recent bout of global warming ended 10,000 years ago, when ocean levels rose 400 feet. We can look forward to 90,000 years of gradual cooling, which is what has happened over the last 10,000 years.

And for your amusement, consider that it only took 5,000,000 years for hominids to evolve from something chimp-like to modern human, and we have this global warming event occurring 10,000,000 years after the dinosaurs died out (more than long enough for another "intelligent" species to evolve and start producing green house gases). So, is this prior global warming evidence of prior intelligent life?

Posted by: Chris Vail at August 28, 2006 02:25 PM

Well, as Georgie Bush says, "Hey, in Biloxi, the casino beaches are beautiful, beautiful. Come on down, my gambler friends. Enjoy your tax dollars at work. Maybe Jesus'll come back while yer there, wave his magic Jesus wand and give ya a heavenly jackpot".

Posted by: Wells at August 29, 2006 11:15 AM