DW: Can you paint a picture of the current state of the world in terms of climate change?

Bill McKibben: Having written the first book about all this almost 30 years ago now, I've had the chance to follow it almost from the beginning. And what's happened is that change is coming much faster and much harder than we would have expected in the late 1980s, when we were first thinking about climate change.

We're now at the point having raised the temperature of the planet about 1 degree Celsius that we can see huge - and I mean huge - changes. This is the biggest thing people have ever done.

Half the summer sea ice in the Arctic is gone, the Earth's oceans are about 30 percent more acidic than they were 40 years ago. Even in the last couple of years, we've lost some huge percentage of the world's coral reefs, and researchers think they will be for all intents and purposes gone by mid-century.

The hydrological cycle — the way that water moves about the planet — has been completely disrupted. California or sub-Saharan Africa goes through these hideous and unprecedented droughts, and then once that water's evaporated up in the atmosphere it comes down as deluge. And so we see absolutely record rainfalls.

I can go on for a long time, but suffice it to say that pretty much everything that we've taken for granted on the surface of the planet is now in major flux. And even those places that seemed idyllic and safe are now places of fear and of flux.

So in terms of climate math, how are we faring?

We've used up most of what scientists have described as the carbon budget. We are producing carbon at record levels, year after year. It's begun to plateau, but at such a high level that it's not doing us much good. If we have any hope of preventing absolute civilization challenge and catastrophe, then we need to be bringing down carbon emissions with incredible rapidity, far faster than it can happen just via normal economic transition.

The goal of the Paris Agreement is to limit global warming to well below 2 degrees Celsius above pre-industrial levels. Scientists widely agree we need to get to zero emissions — or even negative emissions — in the coming decades. Do you think that's achievable?

Well this question comes in two parts: Is it technically achievable? Yes. Mark Jacobson at Stanford [University] is really the guiding authority here. His work demonstrates that in 139 important countries around the world we could get to 80 percent renewable energy by 2030 and 100 percent by mid-century — and do it economically.

The second half question is: Is it politically feasible? That depends entirely on whether we can build movements large enough to break the power of the fossil fuel industry that holds us where we are.

And what hopes do you have of the COP23 conference?

I think that probably the world has done an awful lot of what it's going to do in terms of international agreements at Paris. It took decades to build up the steam for that. And even that was a very modest outcome — if we followed the pledges on the table we would still raise the temperature of the planet about 3.5 degrees Celsius. So it was a start, but to go further what we need are many people in the streets demanding action and pushing governments to move much, much  faster than they're currently contemplating.

President Donald Trump has clearly backed away from any leadership on US climate goals. What hope do you have for the US?

In the short term, there is no hope of the US providing leadership of any kind. As long as Trump is there we won't do a darn thing. And if Trump was somehow abducted by aliens tomorrow his replacement, [current] vice-President [Mike] Pence, wouldn't do anything. For the moment, the fossil fuel industry have their guys in place. I think we have to hope that US democracy will reassert itself before much longer.

Do you place much weight on the role of business and local government in the US to fill the void?

Business and local governments can both do a good deal to fill the vacuum. There are limits to how much can be done, however. They don't call it global warming for nothing. In a logical world, we'd probably have a fully globalized effort to deal with it hard enough with 190 countries. If we're going to deal with it with several million cities and towns, that's going to be harder still. But I'm very glad to see the number of cities that are moving towards 100-percent renewable energy. They're no longer just the kind of obvious blue-state cities, now it's places like Atlanta or San Diego or Salt Lake City that are joining in the march.

Every time we speak — the last time was in April — there seems to be even greater momentum in the global civil movement against climate change. What climate change battles have we seen played out at the local level recently?

There's been a tremendous upswing in these efforts to block fossil fuel infrastructure plans around the world. In the last few weeks, we've seen plans for six big coal ports along the west coast the United States shelved by local action. We've seen the plans for the biggest pipeline out of the tar sands of Canada dropped. We've seen huge agitation that I think will be successful to block the largest coal mine on the planet in Australia. We've seen Scotland become the latest in the long list of countries that have banned fracking. The fossil fuel industry gets nothing for free anymore. There's a fight every time they try to build something new.

And is that a fight you think the people's movement will win?

The question here is not whether we'll win or not. The question is, how fast? 75 years from now, the planet is going to be powered by sun and wind. The question is, will it be a broken planet by that point? Because if we're not able to make this transition very quickly then the inexorable physics of climate change will take us past the point where we'll be able to prevent the worst effects. And that's why there's this great sense of urgency around the world.

There is a sense of urgency but there is also a sense of how overwhelming this is. What advice do you have for those feeling frustrated and powerless?

Well, we are actually are quite powerless as individuals. At this point, the math of climate change is so overwhelming that the actions we do around our homes, they're noble [but] those actions aren't the way we're going to solve climate change at this point. The only thing an individual can do that really matters is become a little bit less of an individual and join together with others in the movements that are big and broad enough to actually change government policy.

Looking into your crystal ball, how do you see the people's movement progressing over the coming decades?

I think it becomes ever-more intelligent. I think we understand better with each passing month the linkages between high finance and the fossil fuel industry. And I think we'll go after them more and more. I think we understand that the imperative now is to push for speedy change — that we're no longer interested in getting people to say that they believe in global warming or to take convenient and relatively easy steps forward. We actually need change on a scale that matches the scale of the damage that we're seeing.

Bill McKibben is co-founder of 350.org and author of "The End of Nature," a popular book about global warming published in 1988.

The interview was conducted by Charlotta Lomas. It has been edited and condensed for clarity.