In February last year, a week after Donald Trump had signed an anti-abortion executive order surrounded by seven men, Isabella Lövin posted a photograph of herself on Twitter signing a climate change bill alongside seven other women.

Sweden’s then deputy prime minister remained enigmatic as the picture went viral and she was asked whether she had been “trolling” the US president. “It is up to the observer to interpret the photo,” she was quoted as saying. “We are a feminist government, which shows in this photo.”

The image made headlines around the world and, nearly two years on, is still what Lövin is best known for internationally. But the Swedish Green party leader and minister for international development is no mere social media politician. During her party’s historic first period in government she relentlessly pushed through an exhausting list of more than 50 policies, including a flight tax, the so-called Swedish Proposal, which tripled the price of EU emissions credits, and the carbon law she was signing in the picture that went viral.

Lövin is one of the leading figures in what she says is a resurgence in environmentally conscious politics across the continent. “There is a green wave going on in Europe, in Germany, Luxembourg and Belgium, and in Finland as well,” she says. “I’m convinced that green parties offer a positive vision, and also the willingness to take on the huge challenges that we see in the world right now.”

The slogan on her Twitter profile, “The climate can’t wait”, sums up the Lövin approach.

“We’ve been very focused on results, and many of these issues have beenfundamental, long-term policies,” she says, sitting in her office in Sweden’s foreign ministry.

“To work seriously on changing policies and setting long-term targets, and forming majorities and doing agreements with other parties, those things don’t pay off very easily in PR strategies.”

It’s the same single-mindedness she as shown ever since bursting into public life 10 years ago following the 2007 publication of Silent Seas – The Fish Race to the Bottom, a rigorously researched, dramatic exposé of the crisis in global fisheries.

“It totally changed my life,” she says of the book, published when she was 44. “But what really changed my life was the decision to write the book. I felt such a huge anxiety and anger about what we’re doing to our planet, and specifically when I understood the issue of overfishing – because we’re actually destroying our oceans with our eyes open.” I decided ... I will try to write about this topic, and then at least I’ve tried’.”

The book was a sensation, winning Sweden’s two main journalism prizes, and launching a process which saw Lövin sent to Brussels as an MEP by the Green party with a single mission: to push through reform of fisheries policies. When I ask if she succeeded, she laughs. “Quite modestly I have to say ‘yes’. I was there for five years and we managed to get a majority in the European parliament to ban shark finning, overfishing and discarding fish, and to bring in a new common fisheries policy that sets the target that we must have sustainable fish stocks by 2020.”

There’s a section in the book when she considers rescuing a dogfish, still alive at a fish auction, and releasing it into the sea. But she bristles when I ask if she sees herself as an eco-warrior. “No, no, no. Never. For me, it was extremely important to really do the research and see the facts,” she says.

“I see the environmental challenges that we have now, they are existential. It’s that serious. It’s not just being like an image, that you’re an eco-warrior or whatever. This is really happening now.”

That is why, when the Swedish Green party formed a coalition with the Social Democrats in 2014, Lövin took the next step and joined the national government, first as minister for international development cooperation, then, when her colleague Åsa Romson resigned, as deputy prime minister and climate minister. “It was tough for me personally,” she says. “But I felt if I don’t do this, I might regret for the rest of my life I didn’t try to do something about the problems I saw.”

Government has also been a bruising experience for the party, particularly at the end of 2015 and the start of 2016, when a dramatic tightening of immigration policy was followed by a failure to stop Vattenfall, the state power company,selling, rather than shutting down, its German coal mines. “One of the mistakes we made … was maybe to say that we would succeed in certain issues where it wasn’t possible, and that has haunted us,” she says, of the coal debacle.

Facebook Twitter Pinterest Isabella Lövin, left, then the deputy PM, with female colleagues signing a climate change bill – the photo went viral on Twitter. Photograph: Johan Schiff/EPA

As a result, the party lost roughly half of its 20,000 members, and then, in September’s election, a third of its seats. The party says, however, it always knew that power would come at a heavy price, and had aimed only to stay above the 4% threshold needed to keep its place in parliament.

I see the environmental challenges that we have now, they are existential. It’s that serious. Isabella Lövin

“It’s been a long-term strategy for the Swedish Greens to come into government and really take responsibility,” says Lövin. “We managed to do that and not be destroyed in the process.”

The Greens may yet have a role in the future Swedish government. Coalition talks have failed to lead anywhere and, last week, Annie Lööf, the leader of the minority Centre party, failed to form a government, the second such doomed attempt. Lövin believes her party is now in a strong position and could find a place in coalitions dominated by the centre-right Alliance bloc or the Social Democrats, whose leader, Stefan Löfven, was on Friday announced as the next person to be put forward to parliament as prime minister.

“It’s difficult to exclude any possibility at this point,” she says. “The Green party has been mentioned now as a very interesting partner for the more liberal rightwing parties, and of course we’re also included in what most people think would be a Social Democratic or more centre government.”

While some other party leaders have spent the last two months locked in coalition talks, Lövin has instead been busy serving as a minister in the transitional government, leading preparations for next month’s Katowice Climate Change Conference.

“I hope to be there,” she says. “I’m very concerned, actually, because with the Paris Agreement, everyone was very happy that we got to get an agreement, but now the logic of the climate negotiations is back to where it was before Paris, with the poor counties, including China and India, blaming the richer countries for what’s happening.”

Lövin’s press secretary then chips in to warn her that it’s time for her next appointment, but she has one more thing she wants to say. “I think one of the most important things for all democracies around the world to contemplate is how we are going to develop and protect democracy when voters are so impatient and learn their news from social media, which can be very biased.”

A viral tweet such as hers may get through to hundreds of thousands of people with a simple message about how wrong it is for a White House full of men to sign orders that affect women’s bodies and lives. It cannot, however, communicate more complicated, nuanced information.

“The understanding of long processes, which is, very necessary if you are going to have a democracy, not a dictatorship, is very low,” she says.

“I think just staying on very superficial messages and going with a populist movement is totally the opposite of what a green party should be.”