It all started with "skolstrejk för klimatet" – the "school strike for climate," also known as Fridays for Future. At 15 years old, Greta Thunberg began spending her Fridays striking in front of the Swedish Parliament to demand action against climate change.

In less than five years, millions have joined Fridays for Future. Thunberg spoke in front of the United Nations. She became Time magazine's youngest ever person of the year. She was nominated for the Nobel Peace prize four years in a row. By 20 years old, she has become a household name around the world... all while finishing high school.

Thunberg has just published The Climate Book. It's a collection of more than 100 essays from herself, scientists, historians, economists, and journalists diving into various topics sharing the data, realities, and proposed solutions to the ongoing climate crisis.

NPR's Ailsa Chang spoke to Thunberg about her new book, her future, and why she thinks change will come from outside the political world.

This interview has been lightly edited for length and clarity.

Interview highlights

On why she put together this collection of essays

I think what mainly motivated me was that it was so difficult to find a source where you could actually read and go in depth on these issues. Because people often ask me, like, "Where can I read? What can I read? What can I watch? I want to get more engaged with the climate crisis. I want to become an activist. I want to learn. But I don't know where to start." So this is a very good place to start. I think it covers a lot of issues concerning the climate crisis. So it's not just a one-sided story.

On if the United States has stepped up in the way that it needs to

I wouldn't say in the way that it needs to. We might see some improvements in some areas, but still, the U.S. is expanding fossil fuel infrastructure. And to do that at a time right now where countless people are losing their lives and livelihoods in a climate emergency that is just continuing to escalate every day. I think that's very, very irresponsible and it's completely absurd.

On how to overcome the political realities of a divided government

That's exactly the reason why the politicians and the people in power need to start speaking up. Because as it is now, they might not have the votes, they might not have the public support from voters to actually take these measures. And of course, how can we expect that? How can we expect people to demand drastic change in order to safeguard our present and future living conditions if they don't know the reason why those changes are needed.

Right now it's like, saving the climate is seen as an act of tree hugging. It's not being seen as a way to protect our civilization as we know it and to save countless human lives. That is being put against jobs and workers, when it's actually the opposite.

The fight for social justice is the fight for climate justice. We can't have one without the other. We can't put them against each other. And unless people know that – unless people know how bad the situation actually is — they're not going to demand change because they're going to want to keep things the way they are.

I believe that the changes will come from the outside, people demanding this, because we see that when there have been successful campaigns. People are raising these issues in a way [that's] been working then that has also had effects on the policies that are being made and the decisions that are being made.

And then, of course, I think that I'm not the one to tell the U.S. how they should do things when it comes to things like Congress and so on. I think that's more up to the experts and the people there.

On whether she will pursue a career in politics

I really hope not. [laughs] I mean, politics as it is now is very, very toxic. And it doesn't seem like the kind of world I would want to spend my life in. I think that I can do more as a campaigner on the outside.

On her experience as an international celebrity

Of course, I don't think it's what anyone expected or could ever expect. So I guess I just have to use the advantage that that gives me. It gives me a platform [where] I can speak up about things that can impact things, people, etc. But of course, it sends a weird message that we are focusing sometimes on specific individuals rather than the actual problem itself and rather than the people actually suffering the consequences of that problem.

On finishing high school and managing a busy schedule

I don't know, [laughs] to be honest. I don't have an answer to that.

On if it's overwhelming

Maybe yes, overwhelming. But I think what's more is the feeling of doing something that matters. Doing something that has an impact. Something that in the future, I will be able to look back at and say, "I did what I could during this existential crisis when most people were just either looking away or were too busy with their own lives."