well we're deeply engaged in the
political process right
around climate change and i've been running this big group three fifty dot org and organizing
things
and that's important that political work is important
but too often politicians think
that this phenomenon climate change is sort of like
dealing with health care or something it's one more problem to
grapple with and
compromise over and whatever that kind of compromise probably makes sense when we're dealing with
something like health care
um... the problem is that
in this case
the contest is not between democrats and republicans not between liberals and conservatives
it's not between china and the u_s_
it's between human beings on the one hand
and physics and chemistry on the other
and that's a very hard confrontation
because physics and chemistry don't actually bargain
they don't yield we now know
that if you put
a certain quantity of carbon in the atmosphere it produces
uh... a certain increase in temperature and it does it whether
you want it to or not
it was actually one of my countrymen svante arrhenius i think it was really the
turn of the last century when he determined
how much carbon would equal how much increase in temperature that's right but that's been borne
out over the years the great swedish chemist arrhenius was really one of the first to
deal with this
uh... and his sort of back of the envelope calculations are
relatively close to what
uh...
we now expect charles keeling who started measuring carbon dioxide levels on mauna loa
in the late nineteen fifties and within a few years it was very obvious that there was
a steady
increase now in fact excelerating increase
in the amount of c_o_ two in the atmosphere and how has that corresponded to the change
in temperature you said that arrhenius' calculations back of the envelope calculations
had been borne out over time specifically i mean what what does it mean we've so far
raised temperature about one degree just under one degree celsius about one point
three degrees fahrenheit
globally averaged
uh... and that's about what we expect we're gonna if we don't get things under control
very quickly
unfortunately we're gonna see another
three four five degrees in the course of this century
very very warm indeed
since we're already seeing and this is the part we didn't anticipate twenty years ago
we're seeing larger responses from the natural world than we would have expected with merely
a degree increase
the melting of the arctic in the summer of two thousand and seven
was an ominous sign it happened well ahead of schedule
it should give us great pause uh...
there are a number of other physical features that are displaying the same kind of flux
rapid melt of glaciers rapid acidification of oceans being
two prominent examples ok and I think as the movement of wildlife toward the poles yes
everything responds to these kinds of temperature changes and so we're seeing
new migration patterns
uh...
new sort of forest
the emergence
and decline of forests in different areas
great swaths of forests across the interior west of the united states and canada
dying from
beetles and things that are no longer kept in check by cold weather i think there
uh... suggesting now that there's a possibility that places like the amazon could wind up
as savannah land instead at some point because of the changes that's correct we don't know exactly
what schedule it's on but that's that's definitely a danger and if that happens well you know
one of the world's great
uh... pumps
is really the world's great pump is brought to a halt plus sink
as well right because the trees there and in other great forests around the world they
tropical forests are less of a sink
then temperate ones
because they're warm um... there's biological activity there all year round
and so the soil microbes in the soil and things continue to
uh... uh...
decay
produce carbon
uh...
and one of the problems we have is that as we warm the planet temperate forests are becoming
in essence more semi tropical with each passing year
and that period of of microbial activity and things stretches longer and they
become less effective as sinks