This is a podcast of Scripps Institution of Oceanography at UC San Diego.
To learn more about how you can support Scripps, visit us online
at scripps.ucsd.edu. This coming March marks the fiftieth anniversary of
the Keeling Curve:
a depiction of rising carbon dioxide levels in the atmosphere,
that has become an iconic image of science. Just as much as models of the
double-helix structure of DNA
or Darwin's finch sketches, the curve has come to represent
a moment when our understanding of nature changed profoundly.
It's namesake is the late Charles David Keeling,
who began a record atop Hawaii's Maunaloa that went on to serve as an early
warning
that humans are capable of changing nature on a global scale.
Keeling inspired a legion of younger scientists,
like Scripps' Andrew Dixon, to make similar measurements in the ocean to
help answer more and more complicated questions about climate change.
Another inspired scientist was Keeling's own son: Ralph,
who recalls the day some thirty years ago when his father mused aloud at the
kitchen table.
The father speculated about how scientist could better understand the
role of land plants in the carbon cycle.
If that could be understood it would help explain where all the CO2 produced
by human activity
was ending up. He dropped the hint
that measuring oxygen in the atmosphere
might be a way to get a handle on that. This wasn't by way of
encouraging me to get into the field or even do this particular piece of work.
But I was absorbing ideas from different directions and that stuck in
my mind and many years later
when I was in graduate school I realized that I might have an idea how to
actually measure these changes in oxygen and
viewed it as something that would be fun to work on.
The program we're now involved with making CO2 measurements in the oceans and most
importantly perhaps reference materials for oceanic CO2 measurements,
first started in discussions I had with Charles David Keeling in the 1980s
where he pointed out there was a real need for standards for CO2 management
so that it would be practical to a mount a global
study of the ocean without relying purely on the measurements of
one single laboratory. The younger Keeling and Dixon are now at Scripps,
making ultra precise measurements of carbon dioxide,
oxygen, and other gases in the air and sea. Ralph Keeling's work
supported by that of Dixon and many others has led to sobering conclusions
about nature's ability to compensate for fossil fuel burning.
But the researchers say their work at least makes it clear what options
society has. The earliest question
was really it was apparent looking at the atmospheric record from Mauna Loa,
that not all the CO2 that was known to be put into the atmosphere
was staying in the atmosphere. It was obviously going somewhere else
and we had no idea how much was going into the oceans or how much was going to
land
once. This ultimately becomes important to understand not only how much is going
into these two additional sings.
but why goes there and how that might change
as climate changes or as land use changes
or as ocean mixing changes in order to be able to predict
likely futures for our life here on this planet.
Well we expected and found that oxygen levels are decreasing with time,
they follow a pattern very much like the Mauna Loa record except in reverse. That
is we see an oscillation that reflects
seasonal growth and
decay of the biosphere.
The trees are growing in the summer
and you see a return of flux of carbon fall and winter when
there is a decay of a leaf litter. A similar cycle affects
oxygen coming from the ocean. So we see this cyclical behavior with superimposed on
that we see a year
year-to-year decrease and that decreases
very nearly explained by the amount of fuel
humans are burning every year-- the amount of fossil fuels humans are burning.
The work of Ralph has shown
that the plants themselves are actually growing a little more
and taking up more CO2. but the lion's share
is now starting to accumulate in the atmosphere
and the increases in the atmosphere are speeding up,
the extent of increase is speeding up with time suggesting that these two major
sinks:
land plants and the ocean really are not capable
of keeping up or mitigating the human effect on the atmosphere.
I think the bottom line is that we're not gonna get our control on this unless
we curtail fossil fuel burning. That's the real bottom line.
We could grow trees to help a little bit, but
it's not going to stop the trend and it's not really going to reverse it
and that's not going to compensate for the huge amount of fossil fuel that we potentially
could go through.
We'll see
ecosystems all over the planet on the run. An ecosystem on the run isn't like
an ecosystem that's been in place for a while, so there will be
disruptions of all sorts. They'll be human migration
because people will not be able to live off the land in the way they did before, mostly
touching on
the developing world
I think, but it'll effect all countries.
My personal fear is that the
pressure to migrate will trigger conflict. In a sense the most immediate
threat to any person is another person.
This will cross into that arena, I'm afraid, particularly
allow it to progress at a rapid pace.
This is Wendy Hunter Barker for
Scripps Institution of Oceanography at UC San Diego.