How Can Gingko Leaves Help Track Climate Change?

Gingko biloba trees have changed so little over the past few hundred million years that researchers can use their leaves to track how the environment has changed over that time. Learn how in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff,
Lauren Vogel Bomb here. You might have a gingko tree
in your neighborhood. It has whispy, fan shaped leaves that
turn a beautiful burnished yellow in the fall, and possibly
drops rotten smelling fruit. It looks different from other trees
you might see on your street, mostly because when you

(00:23):
look at a ginko tree, you're looking at the product
of another time. Gingko baloba is the oldest tree on Earth.
It's outlived all its relatives and has seen the dinosaurs
rise and fall. Any individual gingko tree may have seen
a lot. The oldest known gingo specimen stands in the
Zogan Mountains of China and has one thousand, four hundred
years old. Ginko trees have remained pretty much unchanged for

(00:46):
the past two hundred and seventy million years, have survived
three mass extinctions, and might be a key to helping
us understand something about how our current climate shifts will
affect organisms in the future. A group of researchers at
the Smithsonian Environmental Research Center in Edgewater, Maryland, are studying
a grove of fifteen ginko trees each housed in a

(01:07):
plastic greenhouse tent and hooked up to a tank of
carbon dioxide that delivers different amounts of the gas to
each tree, some up to two and a half times
the carbon dioxide concentration of modern Earth's air. In this experiment,
called fossil atmospheres, the scientists are trying to reconstruct how
the atmosphere of Earth has changed over the past couple

(01:27):
of geologic eras, through the ice ages and periods when
there was no ice at all in the poles, and
how it's likely to change in the future. The Earth's
atmosphere is made up of a variety of different gases,
including carbon dioxide, the concentrations of which have a huge
impact on the planet's climate. Scientists can get a pretty
good idea of what past climates were like by looking

(01:48):
at fossil plants, thanks to a little structure on the
surface of their leaves called stamata. These are tiny holes
that let carbon dioxide into the leaf and water and
oxygen out. The concentration of carbon dioxide in the air
determines how many somata are on the surface of the leaf.
Using fossils of ginkos from different places and time periods

(02:09):
can help the researchers put together a story of what
Earth's climate has been up to for the past few
hundred million years. The researchers are doing all kinds of
experiments with their tented fossil atmospheres, but they also want
your help. You can assist in this project by volunteering
to help count stamata on fossil gingko leaves in order
to calculate the levels of carbon dioxide in the atmosphere

(02:31):
during specific periods in the deep Deep past. You can
also send in ginko leaves from wherever you live, because
although ginkos are native to China, they're popular in yards, gardens,
and along streets worldwide. By receiving specimens from citizen scientists
all over the globe, the researchers will be able to
get a better sense of how various features of the
trees differed depending on whether they're planted in say, Singapore

(02:54):
or Colorado, which will in turn help them to better
understand how ginko grow differently depending on the climate in
which they developed now or two million years ago. Today's
episode was written by Jesselyn Shields and produced by Tyler Clay.
Brain Stuff is a production of I Heart Radios How

(03:14):
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