Faced with daunting challenges ranging from economic turmoil to global
climate change, President Barack Obama's administration plans to "play a
crucial role" in promoting policies aimed at deploying science and
technology in ways that will "turn those challenges into opportunities,"
John P. Holdren told a U.S. Senate committee Thursday.
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Full Transcript below:
Senate Commerce Committee – February 12, 2009
Excerpt: Senator David Vitter (R-Louisiana): OK. Another statement. In
1986, you predicted that global warming could cause the deaths of one
billion people by 2020. Would you stick to that statement today?
Holdren: Well, again, I wouldn't have called it a prediction then, and I
wouldn't call it a prediction now. I think it is unlikely to happen, but
it is ...
Vitter (interrupting): Do you think it could happen?
Holdren: I think it could happen, and the way it could happen is climate
crosses a tipping point in which a catastrophic degree of climate change
has severe impacts on global agriculture. A lot of people depend on
Vitter (interrupting): So you would stick to that statement?
Holdren: I don't think it's likely. I think we should invest effort -
considerable effort - to reduce the likelihood further.
Dr. Holdren, one of the lines in the President's Inaugural Address which
I most appreciated was his comment about science, and honoring that, and
not having it overtaken by ideology. My concern is that as one of his
top science advisors, that many statements you've made in the past don't
meet that test, and so I wanted to explore that. One is from 1971, an
article with Paul Ehrlich, titled Global Ecology, in which you predicted
that, "some form of eco-catastrophe, if not thermonuclear war, seems
almost certain to overtake us before the end of the century." Do you
think that was a responsible prediction?
Well, thank you, Senator, for that..., um..., for that question. First
of all, I guess I would say that one of the things I've learned in the
intervening nearly four decades is that predictions about the future are
difficult. That was a statement which at least, at the age of 26, I had
the good sense to hedge by saying "almost certain". The trends at the
time were not, ah..., were not positive, either with respect to the
dangers of thermonuclear war or with respect to ecological dangers of a
variety of sorts. A lot of things were getting worse. I would argue that
the motivation for looking at the downside possibilities - the
possibilities that can go wrong if things continue in a bad direction is
to motivate people to change direction. That was my intention at the
time. In many respects there were changes in direction which reduced the
possibility of nuclear war through arms control agreements and there
were changes in direction in national and international policy with
respect to environmental problems, including a good many laws passed by
Given all that context, do you think that was a responsible prediction
at the time?
Senator, with respect, I would want to distinguish between predictions
and, ahh, description of possibilities which we would like to avert. I
think it is responsible to call attention to the dangers that society
faces, so we'll make the investments and make the changes to reduce
Well, I will call "seems almost certain" a prediction, but that's just a
difference of opinion. What, specifically, what science was that
prediction based on?
Well, it was based in the ecological domain on a lot of science, on the
evidence of the accumulation of persistent toxic substances in the body
fat of organisms all around the planet, on the rise of the atmospheric
concentrations of carbon dioxide, of sulfur oxides, of particulate
matter, on trace metals accumulating in various parts of the environment
in large quantities, on the destruction of tropical forests at a great
Is all of that dramatically reversed since this "almost certainty" has
obviously been averted?
Some of it has reversed, and I'm grateful for that. And, again, I think
that it's been reversed in part because of sensible laws passed by the
United States Congress and signed by various Presidents. Some of it has
not reversed. We continue to be on a perilous path with respect to
climate change, and I think we need to do more work to get that one
reversed as well.
OK. Another statement. In 1986, you predicted that global warming could
cause the deaths of one billion people by 2020. Would you stick to that
Well, again, I wouldn't have called it a prediction then, and I wouldn't
call it a prediction now. I think it is unlikely to happen, but it is
Do you think it could happen?
I think it could happen, and the way it could happen is climate crosses
a tipping point in which a catastrophic degree of climate change has
severe impacts on global agriculture. A lot of people depend on that...
So you would stick to that statement?
I don't think it's likely. I think we should invest effort -
considerable effort - to reduce the likelihood further.
So you would stick to the statement that it could happen?
It could happen, and ...
One billion by 2020?
In 1973, you encouraged "a decline in fertility to well below
replacement" in the United States because "280 million in 2040 is likely
to be too many." What would your number for the right population in the
US be today?"
I no longer think it's productive, Senator, to focus on the optimum
population for the United States. I don't think any of us know what the
right answer is. When I wrote those lines in 1973, I was preoccupied
with the fact that many problems the United States faced appeared to be
being made more difficult by the rate of population growth that then
prevailed. I think everyone who studies these matters understands that
population growth brings some benefits and some liabilities. It's a
tough question to determine which will prevail in a given time period.
But I think the key thing today is that we need to work to improve the
conditions all of our citizens face economically, environmentally, and
in other respects. And we need to aim for something that I have been
calling for years 'sustainable prosperity'.
Well, since we're at 304 million, I'm certainly heartened that you're
not sticking to the 280 million figure. But, much more recently, namely
a couple of weeks ago, in your response to my written questions, you did
say on this matter, "balancing costs and benefits of population growth
is a complex business, of course, and reasonable people can disagree
about where it comes out." I'll be quite honest with ya. I'm not
concerned where you or I might come out. I'm scared to death that you
think this is a proper function of government, which is what that
sentence clearly implies. You think determining optimal population is a
proper role of government?
No, Senator, I do not. And I did not, certainly, intend that to be the
implication of that sentence. The sentence means only what it says,
which is that people who have thought about these matters come out in
different places. I think the proper role of government is to develop
and deploy the policies with respect to economy, environment, security,
that will ensure the well being of the citizens we have. I also believe
that many of those policies will have the effect, and have had the
effect in the past, of lowering birth rates. Because when you provide
health care for women, opportunities for women, education, people tend
to have smaller families on average. And it ends up being easier to
solve some of our other problems when that occurs.
Final question. In 2006, obviously pretty recently, in an article, "The
War on Hot Air," you suggested that global sea levels could rise 13 feet
by the end of this century. Now, in contrast to that, the IPCC's 2007
report put their estimate at between 7 and 25 inches. So their top line
was 25 inches - about two feet. What explains the disparity? Why is the
IPCC 600% off in their top level assessment?
The disparity, Senator, is that the IPCC chose not to include in that
numerical estimate the mechanisms by which the great ice sheets on
Antarctica and Greenland could disintegrate very rapidly in a warming
world. What they considered is the effect of...
Vitter (interrupting, and inaudible):
No, I don't say it was a mistake. It says so in the report. In the
IPCC's report, it says we're not going to include those rapid mechanisms
because our models are not yet good enough to represent them
quantitatively in terms of how much they could do by a particular year.
My statement was based on articles in the journals Science and Nature,
peer-reviewed publications by some of the world's leading specialists in
studying ice, who had concluded that twice in the last 19,000 years, in
natural warming periods of similar pace to the warming period that we're
experiencing now in part because of human activities, the sea level went
up by as much as 2 to 5 meters per century. And that was not an article
I wrote, that was an interview in which I was quoted, and I had
mentioned that research which had indicated that those high rates were
possible. And the IPCC did not refute that, it simply said, our models
cannot represent the phenomena that did that, so we're going to produce
an estimate that only includes some...
Vitter (who had been trying to interrupt for some time):
So, bottom line, do you think that the better worse case estimate is 25
inches or 13 feet?
The newer analyses that have been done since the IPCC report came out
indicate that the upper limit for the year 2100 is probably between 1
and 2 meters, and those are the numbers that I now quote, because they
are the latest science.
So you would no longer quote 13 feet?
(In background, another member is trying to get the chair's attention,)
I would no longer quote 13 feet, because newer science indicates that
the upper limit is only about six and a half feet.
But going back to my first question...
Chairman Rockefeller, interrupting, as another member continues to try
to get his attention)
Senator, you've had almost ten minutes.
Just a final follow-up. You would say - I think you did - that 1 billion
people lost by 2020 is still a possibility?
It is still a possibility, and one we should work energetically to
Thank you, Mr. Chariman.