JUDY WOODRUFF: The United Nations has released a grim and alarming assessment about the impact
of climate change.
Even worse, it found that countries around the world are not doing nearly enough right
now to slow the damage before it becomes worse.
JOHN CHRISTENSEN, Lead Author, United Nations Emissions Gap Report: The probability of avoiding
dangerous levels of global average temperature increases is dwindling.
If you look at the global emissions, they are still going up.
JUDY WOODRUFF: That's according to a new U.N. report.
It found the planet will have to reduce carbon emissions by 7.6 percent a year between 2020
and 2030.
Instead, emissions have been increasing by about 1.5 percent a year over the past decade.
JOHN CHRISTENSEN: We had a little hope a couple of years ago that the CO2 part of the emissions
had basically been stable for a few years, and we hoped that that indicated a stabilization.
But it started to increase again, and it doesn't look too good.
JUDY WOODRUFF: As part of the 2015 Paris climate accord, nearly 200 countries, including the
U.S., had vowed to take action to limit temperature rise to between 1.5 degrees and 2 degrees
Celsius, or about 2.7 to 3.6 degrees Fahrenheit.
Beyond those levels, scientists warn the climate will reach a dangerous tipping point.
But the goal is slipping out of reach.
Greenhouse gas emissions reached a record level last year, the highest since pre-Industrial
times.
Many countries are not on track to meet the goals of the Paris accord.
And, under President Trump, the U.S. is withdrawing from the Paris agreement, effective next year.
INGER ANDERSEN, United Nations Environment Program: Had we acted in 2010, we would have
had to reduce our emissions by 3.3 percent a year.
Now, because of climate procrastination, which we have essentially had during these 10 years,
we are looking at a 7.6 percent reduction every year.
But the science tells us that we can do this.
JUDY WOODRUFF: If serious action is not taken, the U.N. warned that global average temperatures
could rise as much as 7 degrees Fahrenheit by the end of the century.
The challenge ahead is enormous, and it comes amid daunting estimates over the impact of
what's already happened.
A recent study found that greenhouse gases' warming effect on the planet has increased
by 43 percent just since 1990.
Let's explore some of these questions with a climate scientist.
He is Radley Horton.
He works at the Lamont-Doherty Earth Observatory at Columbia University.
Dr. Horton, welcome to the "NewsHour."
Thank you very much for being here.
I want to ask you, first of all, this sounds pretty dire, I mean, to say that we have got
starting right now to reduce emissions by over 7.5 percent a year, or we face catastrophe.
Is it that dire?
RADLEY HORTON, Lamont-Doherty Earth Observatory: I believe it is that dire, when we think about
the climate risks that we're facing, Judy.
In order to not blow through this 1.5-degree Celsius warming target, just as you said,
we need to reduce our greenhouse gas emissions by on the order of 7 or 8 percent per year.
By 2030, we have to have 50 percent less emissions each year than we do today to avoid the worst
impacts that we could see from climate change.
JUDY WOODRUFF: Where does the fault lie here?
We just -- we heard one of the scientists -- it caught my ear.
He said because of climate procrastination.
Who has been procrastinating?
RADLEY HORTON: Well, the short answer is just about everybody.
Really, to get to where we need to be, we need to see much greater ambition.
Especially, I think, the leadership has to lie primarily with the large economies that
historically have burned so many fossil fuels.
And, remember, these fossil fuels stay in the atmosphere for a very long time.
So, we're still experiencing today warming and sea level rise from emissions, for example,
by the United States, European Union for decades past.
So that's the first place that you have to look.
And those are also the countries that have benefited historically from their greenhouse
gas emissions in terms of economic growth.
So those are the countries we have the look at first.
But the short answer is, we have gotten ourselves into such a pickle now by delaying -- reducing
our emissions that now every country in the world really has to get on board with dramatically
reducing our emissions.
JUDY WOODRUFF: I'm asking because I heard a panel discussion over the weekend where
one of the experts said the U.S. can't wait for China and India, for example, to go first,
because of their population.
The U.S. has to go ahead and move on its own.
So you're saying everybody has got to move right now?
RADLEY HORTON: Everybody has to move, absolutely.
Here in the U.S., I think, by not being more ambitious, and indeed by pulling out of the
protocol, other countries see that as a signal that maybe they can afford to back off a little
bit.
So we need more ambition from everybody.
One thing to keep in mind is even those countries that made pledges for 2020, the only way this
was going to work was if they then amplified and made much more aggressive their emissions
pledges beginning in 2020.
So, what we're actually seeing is many, not all countries, failing to meet the emissions
reduction pledges that they had said they would get to by 2020.
That sets the stage for us needing far more ambitious reductions in our emissions over
the coming decade.
JUDY WOODRUFF: Do you believe it's doable, that this is actually -- that this can be
done?
RADLEY HORTON: So here's the paradox.
Despite all the negative things we have been talking about so far, in some ways, I think
it's more doable than ever, because I think we're starting to see some early signs of
a mass mobilization.
It's still a small amount of gas emissions averted, but when we look at powerful levers
in society, they're showing some signs of activating around this issue.
I'm thinking, for example, about youth movements, people who are saying that they're not going
to accept the way things were done in the past.
When they think about the colleges they're going to go to, the jobs they want to have
in the future, where they're going the make their investments, they are going to be picking
industries that are focused on reducing emissions and focused on thinking about how they're
going to be vulnerable to climate change.
That could, I think, lead to a whole shift of revenues in the future.
That's one example.
We could also talk about what we have seen in terms of renewable energy prices dropping
faster than predicted, battery technology starting to reach a price parity.
We have already hit the point where renewables are outcompeting fossil fuels such as coal
just about everywhere.
So we're seeing signs of that mobilization.
The question is, is it happening fast enough?
JUDY WOODRUFF: And, just quickly, what are some examples of the tough trade-offs that
are going to have to be made?
RADLEY HORTON: So, a few of the sectors that are really, really challenging, we think about
aviation-related emissions.
Aviation emissions are growing roughly 6 percent per year as people fly more.
We do not have a viable substitute right now for fossil fuels for aviation.
Similarly, in heavy industry -- think about things like mining, steel smelting -- those
require fossil fuels.
We don't have solutions today.
So there are no easy fixes there.
In terms of other types of trade-off, even where we see renewables reaching parity, there
are going to be some existing entrenched interests that could suffer in the short-term, but,
for society, as a net gain, we see new jobs, we see new areas of economic growth going
forward.
And, critically, if we quickly reduce our emissions, we avoid or avert some of these
catastrophic damages that we're going to see if we fail to adapt.
If we don't, for example, get emissions down, get sea level rise to slow, think of the costs
we're going to be look at in terms of trying the adapt, trying to build seawalls, having
to retreat from vulnerable areas.
Those costs exceed anything that greenhouse gas emissions reductions could look like.
JUDY WOODRUFF: And just finally, how much of the tough choices that have to be made
are really political choices?
RADLEY HORTON: I think, fundamentally, this is a political problem.
You're absolutely right.
The technology already exists to get us quickly towards where we need to be, those sectors
I mentioned that are thorny notwithstanding.
If we can quickly reduce our emissions in renewables, for example, if we can get the
electric grid off of fossil fuels, if we can get the transportation sector off of fossil
fuels, the land-based transportation, those are things we could do today.
If we do that aggressively, we buy ourselves time for currently pie-in-the-sky technologies
to maybe become viable.
I'm talking here about things like directly pulling carbon out of the atmosphere.
We don't have an ability to do that today, but can we buy ourselves enough time with
the right investments, and maybe in 10 or 20 years something like that will be feasible,
allowing us to actually lower carbon concentrations?
But, to be clear, we're not there today, hence the need for greater ambition across the board
in society now.
JUDY WOODRUFF: Well, it's important to end with at least a piece of an uplifting note
here.
Dr. Radley Horton, thank you very much, Columbia University.
Thank you.
RADLEY HORTON: Thank you.