JUDY WOODRUFF: As we reported earlier, the Intergovernmental Panel on Climate Change,
which is a consortium of climate scientists, announced today that, if the world community
doesn't reduce carbon emissions drastically, millions of people across the planet will
suffer dire consequences.
But, as William Brangham reports, heeding that warning now is a daunting challenge.
WILLIAM BRANGHAM: The U.N.'s latest report put together by over 90 authors and editors
from over 40 countries is probably the starkest, most dire warning yet about the severity of
climate change and the cost of inaction.
The report says that, unless the world immediately begins reducing the burning of coal and oil
and gas that drive up global temperatures, the world will suffer tremendous consequences.
By as early as 2040, just 22 years from now, the U.N. says global food supplies will be
threatened by increasing droughts and heat waves.
Low-lying nations could be flooded by rising sea levels, potentially triggering huge flows
of refugees.
Fierce storms and wildfires will grow in intensity, costing billions in damages and lives lost.
To keep even more drastic impacts at bay, the U.N. report urges the governments of the
world to cut their carbon emissions enough to limit global warming to just 1.5 degrees
Celsius.
That's about 2.7 degrees Fahrenheit above preindustrial levels.
But that would take a near revolutionary change in how the industrialized world creates electricity,
grows food and moves people and goods around.
The U.N. acknowledges that -- quote -- "There is no documented historic precedent for the
changes needed to prevent even worse disasters from coming."
As I mentioned, today's report is to date one of the strongest calls to action.
And with me are two people who have spent their lives studying climate change and our
responses to it.
Rafe Pomerance is a senior policy fellow at the Woods Hole Research Center and chairman
of Arctic 21, a network of scientists working to draw attention to the effects of warming
on the Arctic.
And Gavin Schmidt is a climatologist and chief of NASA's Goddard Institute for Space Studies.
He's co-founder also of the climate science blog RealClimate.
Gentlemen, welcome to you both.
RAFE POMERANCE, Senior Policy Fellow, Woods Hole Research Center: Thank you.
WILLIAM BRANGHAM: Gavin Schmidt, to you first.
This report from the U.N. is, to my reading, an incredibly stark warning.
How do you read it?
GAVIN SCHMIDT, Director, NASA Goddard Institute for Space Studies: Basically, this report
is telling us things that scientists have known for a long time, that climate change
is already occurring, and it really doesn't take very much more for it to become a very,
very serious issue, not just for coastal environments, but for agriculture, for the Arctic, for many,
many different aspects of the planet.
And this report is saying, well, if we want to limit this, if we want it to not get out
of control, we need to act very, very quickly in order to do that.
And the time for doing so is running out.
WILLIAM BRANGHAM: Rafe Pomerance, you have spent decades acting as a bit of a Paul Revere,
trying to get the country to recognize these threats.
And many of our viewers may know you from that very wonderful deep dive that The New
York Times did about our dawning of our understanding of climate policy.
Looking at this report, do you think that this will finally be the thing that moves
the needle?
RAFE POMERANCE: I think this report is really important.
The amount of attention it's gotten has been huge.
It deserves it.
I see each report that comes out as incremental, adding to the public understanding, building
political will.
I don't think there's a report, a single report, that makes all the difference.
So, yes, it's important.
It adds the momentum.
But, in and of itself, it's part of a sequence of events.
WILLIAM BRANGHAM: Gavin Schmidt, let's just say that world leaders decide that they do
want to try to keep warming somewhere near this 1.5 degrees Celsius mark.
What -- how serious, how severe do the emissions cuts have to be?
What do we have to do?
GAVIN SCHMIDT: So, the challenge ahead of us, regardless of where -- what temperature
we're going to end up at, are that we need to reduce carbon emissions by about 70 percent
just to keep carbon dioxide level in the atmosphere.
WILLIAM BRANGHAM: Seventy percent?
(CROSSTALK)
GAVIN SCHMIDT: ... reduce it even more, even more to keep the temperature constant.
And, basically, these temperature targets, 1.5, 2, 2.53, they depend -- what's going
to happen depends on how long it takes us to get to that point.
So, these are very, very large shifts in how we produce energy, how we transport ourselves,
how we grow our food.
And it can't be done overnight.
There's a lot of inertia in the system, not just in the -- in the physical system, but
also in the economy, in innovation, in systems that need to evolve fast in order to get us
down to those levels.
WILLIAM BRANGHAM: Rafe, let's just say world leaders do come to you.
I know you have been knocking on their doors for decades.
And they say, we have seen the light, we want to enact these changes.
What kinds of things -- what are the top things you would like them to address?
RAFE POMERANCE: Well, first, just let me say the prerequisite is political will.
For a world leader to ask the question, they have to have the desire to do that.
And, unfortunately, this moment in the United States is one of our worst.
Our leader says that this problem is a hoax.
So he's taking us out of the negotiations, et cetera.
Given your assumption that world leaders want to step up, there are four areas they have
to work in.
Number one is R&D, research and development, innovation.
We need cheap substitutes.
We can do that.
We're spending some money, but we -- this ought to be a much higher priority on the
national scene.
We have an agency that is supposed to come up with radical solutions, changes.
It's funded at $200 million, $300 million a year.
The Pentagon's agency that does the same thing for the military has had $5 billion.
So this has to be a much bigger priority.
Number two, we need to control the other greenhouse gases, like methane, nitrous oxide.
And where we can, which is mostly carbon and the energy system, we ought to be pricing
it.
The tax is the most efficient mechanism we have.
It needs not only to exist in the United States.
It has to exist globally.
We can do that if we lead.
Without the United States, nothing happens.
The U.S. Congress is the most important body, I still maintain, in the world on this.
And the reason is, they won't act.
And if they won't act, our negotiators can't move.
Now, number three is decarbonization.
We know how to do that through biological systems, like growing forests, improving soil
management and so on.
That takes some carbon out.
Then there's a whole series of technologies that have been proposed to remove carbon.
They're in the early stages.
You have to lower the costs, lower the environmental impact.
But that's another part of the R&D.
And, finally, which this report excludes, is solar radiation management.
I call it the Pinatubo strategy.
It's where you put particles in the stratosphere to reflect sunlight.
It's kind of a...
(CROSSTALK)
WILLIAM BRANGHAM: Pretty dramatic geoengineering.
RAFE POMERANCE: The geo -- dramatic geoengineering.
But we have to understand whether there's a tool there.
We have no research program right now.
We can't tell anybody what the risks are, what -- how clear the benefits are.
We just know that works in the natural world.
WILLIAM BRANGHAM: Gavin Schmidt, you hear Rafe is talking about a lot of possible solutions,
but also rightly signaling that there really hasn't been the political will thus far to
do this.
Do you have any reason to hope that we will change course?
GAVIN SCHMIDT: There's a lot of political will elsewhere in the world and at the local
and federal -- and state levels even here in the U.S.
I find myself talking to people who are involved in local and regional and national, but perhaps
not federal level, efforts that are -- that are really bearing fruit.
And so I think that this notion that everything was -- rests on Congress to fix, I think they
have a role to play.
But there's a lot of movement going on elsewhere in the world, in Europe, in China, in Japan.
There's a lot of new things moving along there.
So I'm not totally in despair.
But the key thing to remember from this report is that it's clear that the best time to have
reduced emissions was 25 years ago.
But the second best time to reduce emissions is right now.
WILLIAM BRANGHAM: Do you have that optimism?
Are you in despair yet?
RAFE POMERANCE: Well, that's not where I go, despair.
It may be warranted, but I don't go there.
WILLIAM BRANGHAM: I just ask this as someone who has been pushing this rock up the hill
for so long.
RAFE POMERANCE: I understand.
Right.
Well, what we're seeing now is -- which we didn't see 40 years ago -- is, we're seeing
climate change impacts in the rear-view mirror.
In other words, everything was sort of projected back there.
It was in the -- it was coming, but we didn't really see -- it wasn't visible.
Now we see that it's happened.
I will give you two examples.
Most of the coral reefs in the world now are dead because the ocean has warmed sufficiently
to bleach them.
Secondly, the Arctic is unraveling.
That will begin to emerge as a major source of emissions if we don't halt the warming.
Then it gets more out of control.
So future generations face huge challenges.
We are in this.
We have to manage it over the long run.
The sooner we get at it, the better.
WILLIAM BRANGHAM: All right, Rafe Pomerance, Gavin Schmidt, thank you both very much.