Transcriber: Tanya Cushman Reviewer: Peter van de Ven
Okay. Well, thanks.
Let me start by pointing out
that we know that human activity is warming the planet
and changing our climate.
We have known for nearly two centuries,
we have understood for nearly two centuries,
the heat-absorbing properties of certain gases in the atmosphere,
so-called "greenhouse gases" such as carbon dioxide.
And we know
that we are increasing the concentration of those gases in the atmosphere
in an unprecedented manner
through human activities, including fossil fuel burning.
We know that the globe is warming.
It's warmed by just under 1 degree Celsius over the past century,
a degree and a half Fahrenheit.
Now, for more quantitative assessment,
climate scientists often make use of physical models of the climate system,
so-called "climate models."
And the critics will often tell you that these models haven't been validated,
they haven't been tested.
But nothing could be further from the truth,
and more than two decades ago,
in the upper floors of this building on the Upper West Side of Manhattan -
building made famous, of course, by the Seinfeld show -
Dr. James Hansen,
director of the NASA Goddard Institute for Space Studies,
was running climate models,
fairly primitive models by today's standards.
Okay.
And what he did was to take that climate model, back in 1988,
and he did several retrospective simulations
using different initial conditions,
and the model did a pretty good job reproducing the observed warming,
shown in the red,
when driven by both natural and human factors.
Now, as Niels Bohr is attributed with having said,
"Predictions are hard, especially about the future."
And Hansen, back in 1988,
did make some predictions about the future.
He looked at three different possible future fossil fuel-burning scenarios,
a low scenario, a medium scenario and a high scenario.
Now, it turns out we more or less followed that medium scenario
with our activity over the ensuing decades,
and the warming predicted by the model
is pretty much spot-on with the warming that we've actually seen.
So that's a very successful two-decade-in-advance prediction.
Now, the critics will also tell you,
well, maybe the warming that we've seen
is partly or even entirely due to natural factors.
Well, we can take the models and subject them to those natural factors:
changes in solar output,
volcanic eruptions, cooling volcanic eruptions.
What the models tell us is that the globe should have cooled in recent decades,
not warmed,
if it was natural factors that were primarily at work.
It is only when we include the human factor
of increasing greenhouse gas concentrations
that we reproduce the warming.
Now, what about the future?
Well, in substantial part, we hold the future in our hands,
which is to say that we could engage in policies
aimed at bringing carbon emissions to a peak quickly
and ramping them down over the next several decades
and keep warming below 1 to 2 degrees Celsius.
We could, on the other hand, continue with business as usual
with our fossil fuel-burning behavior
and end up with warming
anywhere in the range of 3 to 4 degrees Celsius,
5 to 7 degrees Fahrenheit,
by the end of the century.
Now, the precise amount of warming is a little bit uncertain
because the models themselves are uncertain.
Now, in that scenario,
where we warmed the globe by 5 to 7 degrees Fahrenheit,
as James Hansen himself has put it,
we would be leaving our children and grandchildren a different planet.
So if the science is this clear and if the threat is this obvious,
why has there been no action to deal with it?
Well, simply put,
there are major players who profit greatly
from our current addiction to fossil fuels,
and they don't really want to see things change in that regard.
Back in 2002,
there was a memo, a leaked memo, from a Republican pollster, Frank Luntz,
which advised his clients,
basically the fossil fuel industry and politicians doing their bidding,
that there was a narrow window left
to raise doubt in the public mindset about human-caused climate change,
that that window was closing.
If the public became convinced
that the science was solid and that the threat was real,
they would demand policy action to confront the problem.
But there was a narrow opportunity to still manufacture doubt and confusion
and to convince the public
that the science was too uncertain to make policy choices based on it.
This wasn't actually all that new a tactic.
Turns out
it was a page right out of the playbook of the tobacco industry from decades ago.
And we have prominent politicians
who will tell you that climate change is an elaborate hoax.
James Inhofe,
a Republican senator of Oklahoma,
claims that global warming
is the "greatest hoax ever perpetrated on the American people."
Now, it was about at this time, in the early years of the past decade,
when our own work came to prominence,
our work reconstructing past temperatures from so-called "proxy data,"
like tree rings and corals and ice cores,
leading to this curve,
known as "the hockey stick" because of its shape.
Our reconstruction suggested
that recent warming is anomalous in at least the past thousand years.
It became somewhat of an icon in the climate change debate
because of the graphic picture that it presented,
and like all icons in the climate change debate,
it was fiercely attacked by politicians
who deny the reality of human-caused climate change,
despite the fact that now, more than a decade later,
there's a variable "hockey league" -
well over a dozen different reconstructions
using different methods, different data
that all come to the same conclusion,
that recent warming really is anomalous
as far back as we can extend these sorts of estimates.
So, what we've been subject to
some would call "the politization of science."
But I like to call it "the scientization of politics,"
which is to say it is the use of science,
or more specifically,
attacks against science and scientists
in an effort to advance a political agenda.
Now, back in summer of 2005,
just as I was getting ready to come to State College
and begin my position here at Penn State,
I received a note from Joe Barton,
the Republican chair of the House Energy and Commerce Committee.
Mr. Barton essentially was issuing a subpoena
for all of my documents, email correspondences,
notes from my entire career
and the same for my two coauthors on the original hockey-stick picture.
Now, this was before Joe Barton became a household name
when he was heavily criticized for his infamous apology to BP.
But at the time, back in the summer of 2005,
he was also heavily criticized
by editorial pages of newspapers around the country
for what was widely seen as an effort to intimidate scientists
whose message was inconvenient
to the special interests that he represents.
And major science organizations and societies, the journal Nature,
came to our defense,
blasted Barton for this attempt to chill scientific discourse,
and politicians, importantly, from both sides of the aisle,
condemned what they saw as thinly veiled, modern-day McCarthyism.
Now, the attacks didn't stop there.
In fact, the latest - I haven't said anything yet -
(Laughter)
the latest salvo in the wars against climate science
came two years ago, almost to this day,
when criminals broke into a university server in the UK
and stole thousands of emails between scientists,
and then cherry-picked these emails for words and phrases
that could be used to make it sound like scientists were fudging the data,
that scientists were engaged in some sort of impropriety.
In fact, in the days leading up -
this all happened, by the way,
in the weeks leading up to the Copenhagen Summit,
the most important opportunity yet,
at that point,
to deal with the problem of climate change.
Perhaps that's just a coincidence.
There was an op-ed written by Sarah Palin,
arguing that these emails revealed that scientists were fudging the data.
I was allowed to write an op-ed in The Washington Post in response,
pointing out that pretty much everything she had said in her column was wrong.
(Laughter)
To her credit, she did ultimately say
that a lot of these emails obviously weren't meant for public consumption,
and she said that they could be misinterpreted
"if taken out of context."
That was just last summer, June 2011.
Of course, she was talking about her own emails
that had been released under a Freedom of Information Act demand
from the time that she was governor of Alaska.
Well, this campaign, the so-called "ClimateGate Affair,"
was seized upon by the usual suspects.
James Inhofe, who you may remember from a few minutes ago,
in a line almost out of "The Manchurian Candidate,"
found 17 climate scientists who should be prosecuted
for their supposed indiscretions as revealed in these emails.
And it didn't stop there.
That spring, Ken Cuccinelli,
the newly minted attorney general of Virginia -
oops - that's the wrong Cuccinelli scandal.
(Laughter)
Ken Cuccinelli,
the attorney general of Virginia,
taking a page right out of the playbook of Joe Barton from several years earlier,
issued a civil investigative demand, a subpoena essentially,
once again, for all of my correspondences
with more than 30 different scientists around the world
from the time that I was at the University of Virginia
for the supposed fraud of climate change.
And he was heavily condemned,
even by newspaper's editorial boards that had supported his candidacy.
The Washington Post published no less than five editorials,
blasting Cuccinelli for, once again,
a fairly self-evident attempt to chill scientific discourse
disadvantageous to those special interests he represents.
And even the award-winning cartoonist Tom Toles, at the Washington Post,
couldn't resist commenting on the matter himself.
(Laughter)
That is my favorite too.
(Laughter)
Okay, and the usual groups,
public interest groups like AAUP, the Union of Concerned Scientists,
even the conservative group Fire,
came out and once again condemned
these efforts to intimidate scientists.
The major scientific organizations and groups -
AAAS, NCAR, Nature -
issued a editorial.
And Al Gore spoke out about this latest attack.
And ultimately, his subpoena was quashed, okay.
So that was at least a momentary victory
in the various battles being waged against climate scientists,
but it didn't last long.
By that next fall,
congressional Republicans
who were preparing to regain control of the House
indicated that they were going to hold a series of show trials,
once again attacking climate scientists.
And fortunately, members of their own party,
like a true hero, Sherwood Boehlert,
the former Republican chair of the House Science Committee,
came out and warned his fellow Republicans
that they were very much in danger of becoming the party of anti-science
and they should not go down this road.
And it seems to have at least helped out a bit.
So I would like to quote Edmund Burke:
"All that is necessary for the triumph of evil
is that good men" -
it should be, today, men and women -
"do nothing."
Fortunately in this case, good men and women didn't do nothing.
Politicians on both sides of the aisle,
politicians of conscience,
came out and defended science and scientists
when it was under attack.
So assuming we can get past this somewhat silly debate
in the public discourse
about whether the problem is real,
whether the threat is real,
What can we actually do about it?
Well, there are, of course, things that each of us can do individually.
If you have the carbon footprint
of a Sasquatch,
there are many different things that you can do
to become more of a Cinderella.
Ultimately, there's no magic bullet, though.
If we are going to decarbonize our economy,
we're going to have to, obviously,
support policies that incentive clean energy,
non-carbon-based energy sources.
We may have to consider some difficult choices along the way
as we try to find a bridge to a future carbon-free economy.
And politicians across the political spectrum
have to come together to solve this problem that threatens us all.
Climate change doesn't care whether you're Republican or Democrat;
it's going to affect all of us the same.
Finally, I'd like to leave you with this picture of my daughter
underneath the polar bear pool at the Pittsburgh Zoo.
The point I'd like to make here
is that climate change isn't simply a problem of politics or economics,
it's a problem of ethics.
The choices we are making today
are going to determine
the world that we leave our children and grandchildren.
There's still time to make the right choices.
Thank you.
(Applause)