At a time when the science of global warming is under attack and many people complain of climate change fatigue, some cheering news occurred last month: A book about climate change became a New York Times bestseller in its first week of publication.

Kolbert’s book warned of cataclysm; Hawken’s tries to prevent it. Bringing together geologists, engineers, agronomists, climatologists, biologists, botanists, economists, financial analysts, architects, NGOs, activists, and other experts, Drawdown offers 100 solutions to reverse global warming.

View Images Photograph courtesy of Penguin Random House

When National Geographic caught up with Hawken at his home in San Francisco, he explained why climate change is a gift, not a curse; why empowering girls and women is the number one solution; and what role musk ox, reindeer, and wolves have to play.

Let’s start with a definition. What is “Drawdown”? And how is it different from other methods of tackling global warming?

The idea for Project Drawdown goes back to 2001. There has never been an attempt to map, measure, and model the 100 most substantive solutions to global warming. There has been a tendency to silver bullet the problem, which is to look for the big solution: the Archimedean lever. If you just find it and pull it, somehow we're going to get rid of this problem and stabilize emissions.

That's simply not true. All of us have heard again and again that if we go to solar, wind, and renewable energy—and maybe electric vehicles and storage—prevent deforestation, and reduce meat consumption, we will get a hall pass to the 22nd century.

Those solutions are crucial to achieving drawdown as well, so I'm not in any way diminishing their importance. I'm just saying a great number of salient, important solutions are often left out. That’s why we include 100 different strategies.

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Michael Pollan, the writer and activist, once said that the biggest question facing us with regard to climate change is: Why bother? Have you got an answer for us?

I see it as a gift not a curse. Why bother means game over. I actually see it as game on. It's a different point of view. Climate change is feedback, and any system that doesn't incorporate that feedback is stupid and fails and dies. Here, we have feedback, and the feedback it's giving us is a pathway to a much better world than the one we live in now.

This is not a path to retrogression or a future that we won't like. It's actually to a much better future: cleaner, healthier, with more jobs, more security, and more life on the planet. What climate change is offering us is actually a new way of seeing ourselves, our relationship to each other, and all living beings on this planet, which can be extraordinary in terms of imagination, innovation, creativity, and real breakthroughs in human thinking.

President Trump recently introduced a global gag rule on family planning. Explain how this will also have a powerful, negative effect on climate change.

What he's done is simply project ignorance to satisfy his right-wing supporters. I think it will have some effect, but not much. The idea that the United States is all-powerful is an American illusion.

As regards family planning, the United Nations has a three population projections for 2050—high, median, and low. The highest is 10.8 billion, the median is 9.7 billion. The difference between the high and the median population projections comes from family planning. There are two pathways. One is to provide education for girls in those countries where they are taken out of school in fifth and sixth grade, and married off, because of cultural, religious, or other forces. Those girls tend to have five children or more. But if a girl is allowed to continue education and pass tenth or eleventh grade, her reproduction rate falls to two—which is why the empowerment of girls and women is the number one solution to global warming.

View Images Bike racks, like this one in Copenhagen, can get crowded in Denmark, where 18 percent of local trips are done by bicycle. Photograph by Jason Edwards, Nat Geo Image Collection

Nuclear energy is a controversial choice as a solution to climate change. But China is showing a new way forward—ironically, with a technology developed, then shelved, by the U.S.

Molten salt reactors were first developed at Oak Ridge National Laboratory, in the 1950s. I don't know why we dropped it but I do know the Chinese have picked it up. [Laughs] The nuclear power industry in Europe and the U.S. has pretty much come to a stop. The plants under construction are way over budget, nobody wants to finance them, nobody will insure them except the governments themselves.

But in China and Asia, that's not the case. The Chinese are building them at a very rapid pace at a much lower cost. Many people objected to us including it, and I don't think safety in the long term, in terms of plutonium storage, has been solved. But certainly some of the new reactors are much different in terms of their impact.

Architecture is increasingly playing a role in combatting global warming. Tell us about “cool roofs.”

Cool roofs are roofs that either reflect the heat back, in the sense of white roofs, or green roofs that have foliage and perennial plants. Each provides a different mechanism to cool the building underneath. White roofs are particularly suitable for tropical areas or areas where there’s high radiation.

When you fly into Los Angeles, you'll see more and more white roofs. It's actually a very simple technique. Green roofs can be installed anywhere, whether in tropical or temperate climates. They have a marvelous insulation factor. They are big in Germany and Canada, as well as the U.S. and the U.K.

View Images Self-driving cars, like these lined up at Uber Advanced Technologies Center in Pittsburgh, Pennsylvania, could encourage people to give up automobile ownership. Photograph by Angelo Merendino, AFP, Getty Images

In Denmark, 18 percent of local trips are done by bicycle. In the Netherlands, it is 27 percent. But in the U.S., the figure is just 1 percent. How can Americans be persuaded to swap four wheels for two? And what effect would that have on global warming?

The United States is a car-loving culture and has designed its cities and roadways in such a way that it's dangerous for bicycles to be on the roads. As a result, it is one of the most dangerous places for bicycles.

But if you create infrastructure for bikes, people will use them, even in the north. Look at Denmark. The phrase “build it and they will come” is true for bicycles. If people see a safe lane for a bicycle, the invitation is there and they will begin to explore doing it themselves.

This can have a huge impact on health and well-being, but also the number of gigatons of carbon we need to reduce by 2050. The overall cost is negative compared to building more roads or more mass transit. It's a win-win strategy cities can take, both in terms of municipal budgets, health, and the reduction of pollution and traffic.

We all love to travel but, worldwide, flights produced 781 million metric tons of CO 2 in 2015. How can this gargantuan figure be lowered?

Aviation is the source of 2 to 3 percent of global CO 2 emissions, and all the big aircraft companies are working on solutions. But they have to think 30 years out; it takes a long time to design a plane and ensure its safety. That is due to extraordinarily careful engineering.

There are a whole series of new technologies being applied in the lab and in test aircraft, from the shape of fuselages to placing jet engines at the rear of aircraft, in order to save on weight. The Germans are developing something called “late descent.” The way aircraft are marshalled in and out of airports, or taxi on the runways, is a significant cause of CO 2 emissions. What you see now are operational shifts in take-off and landing that can reduce fuel use from 10 to 30 percent.

Aviation companies are also talking about designing planes that will actually be electric or run on biofuels. It's a very different mode of transport. It’s very quiet and will save 40 to 50 percent of the energy that’s presently being used by aircraft. It's an area of great innovation, except I would be patient because it does take a long time.

View Images China is building relatively cheap, small nuclear reactors, like this one in Changjiang. But longterm safety remains a concern. Photograph by VCG, Getty Images

Towards the end of the book, you describe some futuristic ideas that may soon become reality. Tell us about the idea of repopulating the mammoth steppe.

Repopulating the mammoth steppe is in some ways my favorite. The mammoth steppe is a subarctic region that used to stretch from Alaska to Canada, all the way across Europe and into Russia. Now, it's just Russia. It was the world's largest grassland. But 12,000 years ago, human beings swept in and wiped out all the animals.

Now, two biologists, Sergey Zimof and Alexander Sergeev, want to create the Pleistocene Park to repopulate the mammoth steppe with animals that were originally there, except for the woolly mammoth, which is extinct. Elk, wolves, reindeer, or musk oxen eat the dead grass underneath the snow by pushing the snow away with their horns, snouts, or hooves. In so doing, they reduce the temperature of the soil in the subarctic by two degrees Celsius, which then enhances the ability of that area to retain its permafrost.

Nothing is more futuristic than a car that drives itself, which is why Apple and Tesla, as well as traditional manufacturers like Ford, are all racing to develop one. Trouble is, they keep crashing. Is there a future for autonomous vehicles—and what effect would they have on climate change?

The whole issue of mobility is up for grabs. Do we really need a 4,000-pound car to deliver a 120-pound woman to the supermarket? I don't think so. What we're looking at is a very different relationship between human beings’ mobility and autonomy, in terms of vehicles. Opinion is divided. But if it's done properly, it means a 40 or even 60 percent reduction in the total number of cars on the road, or in garages, because that's where they are most of the time. A car is only used 4 percent of the time. The other 96 percent it is idle.

If we have mobility at our fingertips—which is to say, I need a vehicle, I need a pod, something to take me from here to there, and it arrives quickly and is safe—then we can say, I don't need a car, especially in urban environments. It can not only reduce the amount of vehicles being produced in the world. These vehicles can also be electric, charged by renewable energy, like wind.

It would also have a big impact on roads because these cars are smaller and don't need the same kind of infrastructure. They're talking about making roads that are narrower, returning cities more to pedestrian-scapes instead of road-scapes, expanding sidewalks and cafe areas. It also has a tremendous impact on sound, because these vehicles are very quiet.

Some of them have crashed, but we also have to remember the amount of vehicular deaths and carnage caused every year by existing vehicles. Given the rate of innovation in the technology, I have no doubt that it will be achieved successfully.

This interview was edited for length and clarity.