DW: What would you say are the greatest environmental problems we're currently facing?

Erik Solheim: One is pollution, and pollution of course is the key also to climate change; if we really fight pollution, we will solve the climate problem. And the other is the decline in so many of the most iconic species, and the beauty of the nature — the elephants and the rhinos, and of course a huge number of animals here in Germany.

In terms of biodiversity and extinction crisis that's happening, how would you assess that battle?

That is probably, of all the big battles at this time, the one we are losing most. We are now at a turning point when it comes to pollution and climate. But we need to do a lot more to protect our sisters and brothers — I mean, the elephants and the orangutans, all the insects, and the bees, and the flowers.

We need more natural reserves and protected areas and we need to find a better coexistence of animals with humans. For instance, do agriculture in a way so that it doesn't destroy the biodiversity, or the very simple thing, make bypasses for animals when you build new roads.

What do you think is the direction that the world needs to take to combat pollution?

We need to mobilize citizens to demand action, we need governments to regulate markets, and we need business to find the practical solution. Let me give you one example: We are overwhelming our oceans with plastic. Everyone understands the need to change. We may be living in a world in 2050 where the weight of plastic in global oceans is like the weight of fish — that must change. We see whales, turtles, sea birds, even camels and cows eating plastic all over the planet. And also, it's very dangerous for us, because through fish we can get it into our bodies. So we need to change. We need business to find much better products, and we need governments to regulate markets. For example Kenya with Rwanda and Eritrea — three African countries — have now completely prohibited plastic bags and see immediate positive results in nature.

It seems that there is often a lack of political will to tackle environmental problems. How can this be overcome?

I tend to disagree. True, there is some disappointment with the president of the United States of America. But at the same time, you see president Xi Jinping of China speaking more about the environment than about the economy, saying that green is the new gold, that China should move to an ecological civilization. And the same in India with prime minister Modi — and frankly, Chancellor Merkel has put Germany on the Energiewende, which will produce an enormous amount of new technologies and provide an important number of jobs.

What should the role of the economic sector be in environmental protection?

Governments must regulate markets and give a vision, otherwise they cannot work. Then business should be innovative, and they should bring things to scale, not just some small projects here and there. As an example, you need a complete new plastic economy, it goes without saying that if business can provide artificial intelligence, put people on the moon, cure cancer, they can produce better plastic products which degenerate in nature and do not destroy our oceans. Just put sufficient pressure on business from political leaders and opinion, and it will happen.

You talk about a change of behavior. What is that about?

Oh, it's about: you vote for the most environmentally friendly politician, that matters. When going to a shop, ask the supermarket why there is an enormous amount of plastic around two apples. Why do we need that? Why do we need straws? Your mother, my mother, lived their entire life without straws. The average North American uses 600 straws a year, and quite a few of them ending up in our oceans. We don't need them. Why don't you just change, and stop using them? 

The Paris Agreement set out to limit the global temperature rise to well under 2 degrees. Some experts say we've overshot 1.5 degrees, some even say 2 degrees is not realistic. What do you think?

I believe change can happen much faster than some others think. Remind yourself that 10 years from today, back when Steve Jobs in California held up the first digital phone in the world. Now, more than 50 percent of humanity has digital phones, it's getting everywhere. So of course when the price of solar and wind comes down at this speed, they would take over the market much faster. If governments regulate, we will see electrical cars coming into the cities much faster than people believe today. But you need this combination of market and political leadership.

What should be the plans for dealing with the increasing number of climate refugees?

We need to look into how climate and conflicts work together. Somalia is a clear example, 1 million people had to move because of terrorism, war, drought and climate change. All this has come together, but it is hard to distinguish, so we need to look at the much bigger picture and deal with environment and conflict problems at the same time.

In terms of regular people, what can they do to protect the environment?

Buy environmentally friendly products, when you want to buy a new car, look for the new BMW or Volkswagen which is electric — go for biking, walking if you can. And of course vote for political leaders who are green. Put pressure through media, through social media, for green development — there is such a lot people can do. Lots of young people come to me and ask, can I do something, does it matter what I do? The answer is yes. No one else can change the world — you can change the world.

There are many reasons to be optimistic. We humans caused the problems, we can also fix them.

Erik Solheim is the Executive Director of the United Nations Environment Program.

The interview was conducted by Sonya Diehn at the Global Landscapes Forum in Bonn, Germany — it has been condensed and edited for clarity.