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Weathering Rocky Change In The Climate
About 251 million years ago, the Earth experienced one of the
largest mass extinctions of life that has ever occurred. More
than 95 percent of sea species and more than 70 percent of
land species expired – and scientists still do not know exactly why.
neil tabor’s research on ancient soils and climates may help to
bridge that knowledge gap. His work has taken him to every continent.
Now his focus has turned to West Texas and the geologic
formations of Caprock Canyon and Palo Duro Canyon. Their rock
exposures date from an interval of time called the Permian-Triassic
Boundary, during which that catastrophic die-off occurred.
“This area and I have a long history together,” says Tabor, an assistant
professor in the Roy M. Huffington Department of Earth
Sciences in Dedman College. Tabor, who received his Ph.D. from
the University of California-Davis, made his first field excursion
as a graduate student to the Caprock and Palo Duro sites.
“I’ve wanted to return to these strata for about 13 years now,” adds
Tabor, who began his current research there this spring. “It’s fortunate
that we have these rocks in Texas because there aren’t many
places on the planet that still have them from that particular age.”
Tabor and a team of students are collecting
samples and analyzing their chemical composition
in SMU’s labs. From the data he plans to
collect over the next several years, he hopes to
reconstruct the environment of the Permian-
Triassic Boundary and how it changed. That
timeline may help reveal whether those climate
changes triggered the catastrophic population
collapses of life forms that existed during
that period.
The data Tabor has collected from similar sites
in Argentina, Ukraine and northwest China
show “a very, very strong relationship” between
estimated atmospheric carbon dioxide (CO2)
levels and temperature. “When CO2 rises, it appears
that temperature rises in the atmosphere.
And polar ice sheets are breaking up in direct
response to the increased concentration of atmospheric
CO2,” he says.
Scientists can estimate an era’s temperature
through the isotopic combination of minerals
that form in the soil, Tabor says. What they see
is that over the past 65 million years, CO2 levels
appear to increase as temperatures rise. Tabor’s
research suggests that for each doubling of atmospheric
CO2, “we can expect temperatures
to increase on the order of about 2 to 3 degrees
Celsius,” he says.
Currently, researchers anticipate a doubling of pre-industrial
CO2 levels by 2100.
If those predictions come true, “it means
that people in Omaha, Nebraska, can expect to have weather a
lot like current-day Dallas, Texas, by that time. And if you live in
Miami, you’ll have to buy a houseboat, because many coastal
areas will flood.”
Additional research could have important implications for
global climate change policy and action, Tabor says. “I think the
best way to evaluate how increased atmospheric
CO2 levels and emissions will
affect our global climate is to go back
through the geologic record,” he says. “It’s
the best way to assess how to adjust policy
and practice for the future.”
For more information:
smu.edu/ earthsciences/people/faculty/tabor.asp
