"The evidence is overwhelming. There's no question that the Earth is warming and we're having a role in it." - Asst. Prof. Amy Frappier (Geology and Geophysics)
Warming to the Task
BC geologist Amy Frappier looks to the past to find answers about climate's future
By Stephen Gawlik
When it comes to the weather, Asst. Prof. Amy Frappier
(Geology and Geophysics) tends to have a different
While most people concern themselves with what the weather
is going to do on a daily basis, Frappier, a paleoclimatologist,
is far more interested in what the weather did - thousands
of years ago.
"We have only a relatively short recorded history,
but we can take a look back at old clues and try to
use them to see what's coming," said Frappier,
who joined the Boston College faculty last semester
after completing her doctorate at the University of
As a public debate about global warming continues and
the chorus demanding legislative, political and industrial
changes reaches a crescendo, it is researchers like
Frappier who are working to provide empirical guidance
about the planet's always-shifting climate.
"The evidence is overwhelming," she said.
"The globe is warming and we want to know what
to expect so we can be prepared."
For her part, the Rhode Island native is one of a small
but growing contingent of scientists in her field -
paleotempestology, the study of ancient storms - who
are seeking clues about the history of Earth's changing
climate as found in certain natural "archives"
such as tree rings, sea shells, polar ice cores and
Frappier is credited with developing a method for decoding
the record of hurricane rainfall preserved in tropical
cave formations such as stalagmites. The details of
Frappier's methodology and its results will appear
in a paper published in this month's issue of Geology.
Frappier, who spent an undergraduate semester while
at the University of Maine living in Antarctica, sees
undeniable evidence of climate change both in her many
research trips to the Caribbean - and also right here
at home in New England.
"There's no question that the Earth is warming
and we're having a role in it," says Frappier.
An avid cross-country skier - "I think this has
been a tough year for all of us who enjoy winter sports,"
she says - Frappier says there is ample firsthand evidence
that things aren't what they used to be as far as the
New England weather patterns are concerned.
"Look at how many small ski slopes have closed
and look at how much artificial snow the big ones have
to produce," she said. "That was unheard
of 50 years ago.
"There are more heat waves in summertime and we're
seeing a change in the growing season, the last frost
comes earlier in spring, and the first frost is later
in the fall."
Frappier's research, however, is focused on the tropics
because those regions are home to most of the world's
population, and are most likely to be sharply affected
by whatever climate changes are happening.
"I am exploring new Caribbean cave records of
pre-historic hurricane activity to illuminate how global
climate change is likely to affect hurricanes and vulnerable
coastal populations in the future," said Frappier.
The more traditional method of this research, she explains,
involved digging sediment cores from coastal lagoons
and marshes. Stalagmites, she said, offer a different
and more detailed "story set in stone."
Stalagmites are mineral formations that grow up from
the floor of caves as mineral-rich water drips from
the cave ceiling. All cave formations are created slowly
over time, at rates that vary from an inch in 1,000
years to as fast as an inch in 20 years. A change
in the isotopic character of oxygen in rainfall from
hurricanes alters the chemical composition of the water
descending through the rock into the cave, says Frappier.
These changes are recorded as variations in the oxygen
isotope values in the stalagmite's calcium carbonate
composition. Stalagmites contain visible growth bands
that can be counted like tree rings and, using a computer-controlled
dental drill to collect samples, researchers can tell
when in the past the region experienced hurricane rains.
The number and intensity of hurricanes in the region
will tell researchers something about the links between
climate and storms, she says.
"Changes in the water that came through the cave
result in really brief variations which we can mathematically
distinguish from the rest of the record," Frappier
says. "We have cross-checked this with historical
storms and the correspondence is remarkable."
Frappier began following this line of inquiry while
in graduate school as she came upon a research article
that discussed the isotopic differences in rains caused
by hurricanes. At the same time, she met another graduate
student who was studying caves in Belize to ascertain
what sort of climate the Mayan people experienced at
the height and decline of their civilization. Frappier
put the two pieces together and developed the methodology
for indicating exactly when and with what intensity
hurricanes appeared since the last Ice Age.
"I figured either this was impossible, or someone
was doing it already," she said, noting that others
had attempted this research many years ago, but didn't
have the technology required to detect individual storms.
That all has now changed, she said.
For Frappier, the interplay between humans and nature
has been a life-long interest. As an elementary school
student in northwestern Rhode Island, she witnessed
a dispute between people who wanted to preserve local
wetlands and a city that wanted to build a sewer in
an area behind her home.
"The whole idea of how people live in the environment
while protecting it became an interesting dynamic to
me for a very long time," she said.
As the conservation-versus-development debate continues
to take center stage internationally, Frappier says
it is more vital than ever before to make sound environmental
"The choices we all make in the next decade are
going to be very important in determining the climate
our children inherit," she said.