Arctic’s Long-Lost Forests Show Carbon Links, Scientists Say
By Jim Efstathiou Jr.
Nov. 26 (Bloomberg) -- A warm period 3 million years ago, when forests dotted the Arctic region and sea levels were 80 feet (24 meters) higher, is providing clues about how heat-trapping greenhouse gases can boost global temperatures, scientists said.
Fossils from the mid-Pliocene epoch reveal a far warmer planet with a concentration of carbon dioxide in the atmosphere of only about 5 percent more than exists today, said Harry Dowsett, a U.S. Geological Survey scientist. A reconstruction of the climate 3 million to 3.3 million years ago shows slight increases in CO2 may produce large temperature changes, he said.
The new data from fossilized plants and plankton are a window into how CO2 and other gases produce a greenhouse effect that’s blamed for the current global warming. The world then was as warm as that predicted for the end of the century by some climate scientists, Dowsett said. The findings may be used to improve forecasting models, which have been criticized by some climatologists for improperly predicting temperatures.
“Possibly the most important reason for attempting a global reconstruction for this time period is that it can be used to test and refine climate models that are used to estimate future warming,” he said in an interview yesterday.
Dowsett is lead scientist for the USGS Pliocene Research, Interpretation and Synoptic Mapping project, which aims to model the climate of the mid-Pliocene. He is also lead author of a new report by scientists on the sensitivity of the climate to changes in CO2 levels published in the online edition of Philosophical Transactions of the Royal Society.
Similar Warming Forecast
Data from the mid-Pliocene period suggest average temperatures were about 2 degrees Celsius (3.6 Fahrenheit) warmer than today. A 2-degree Celsius increase is within the range that the United Nations Intergovernmental Panel on Climate Change has forecast for the end of the 21st century.
Atmospheric concentrations of CO2, the main man-made greenhouse gas, were about 400 parts for every million parts of air in the mid-Pliocene. CO2 levels rose to 383.1 parts per million in 2007, the UN’s World Meteorological Organization said yesterday in its annual Greenhouse Gas Bulletin from Geneva.
The causes of the ancient warming are not completely understood. They are believed to be a combination of increased greenhouse gases from natural sources and a greater impact by ocean currents in moving warm water to cold regions, according to an analysis on the Web site of the Pliocene research project.
When reconstructing Arctic Ocean temperatures in the Pliocene period, “we’re seeing maybe 16 degrees Celsius temperatures,” Dowsett said. That “would suggest a great deal of heat being transported by the surface circulation from the tropics to the poles.”
Models Criticized
Models that simulate ancient climates have drawn criticism for being incomplete. While warming does appear to be occurring at a constant rate, as climate models predict, the calculations generally overstate the amount of temperature increases mankind faces, said Patrick Michaels, senior fellow for environmental studies at the Cato Institute, a Washington public policy research group.
“Models should be used more to generate questions than to generate policy,” Michaels said in an interview yesterday. “The problems that the models are having with the current climate certainly would make one at least slightly skeptical about simulations of past climate.”
USGS researchers used micro fossils from deep-sea and land- core samples to isolate plants or species that lived 3 million years ago. The fossils reveal global temperatures, the amount of ice on the planet and the extent of vegetation cover.
Imperfect Comparison
The data is being used to refine computer models that aim to predict future climate, Dowsett said. He cautions that plants and organisms may react differently today than they did 3 million years ago.
“Remember, we’re going back 3 million years,” Dowsett said. “You can’t just read it and say yeah, we’re done, we know what the future looks like.”
James Hansen, director of the U.S. Goddard Institute for Space Studies who in 1981 warned that emissions were heating the planet faster than expected, said CO2 levels already are too high. In a study this month, he said heat-trapping emissions should be reduced below current levels to avoid the worst effects of climate change.
To contact the reporter on this story: Jim Efstathiou Jr. in New York at jefstathiou@bloomberg.net
Last Updated: November 26, 2008 06:10 EST
It's not really hard to start connecting all the dots, when you look at ocean acidity levels, CO2 increases, human industrial CO2 output measurements, ice core patterns showing the last 800K years of CO2 and temperature levels, deforestation levels, rising extinction levels, fishery die offs in the ocean, unprecedented swings in ice cap melting, increased size of dead spots in the ocean, increased size of the hole in the Ozone, etc etc. What does it all point to? Is it all just coincidence and the product of some global conspiracy? |
