At the end of last summer, a 15-year-old girl sat on the cobblestones outside the Swedish parliament with a placard that read: “School strike for climate” and handing out leaflets saying: “I am doing this because you adults are shitting on my future.”

Nine months later, and Greta Thunberg, now 16, is at the UK parliament telling politicians who have flocked to see her that they have lied to her generation, that they are destroying children’s futures, and that the country’s current fossil-fuel policy was “beyond absurd” and will remembered in history “as one of the greatest failures of humankind”.

In response, they laughed politely at perceived jokes in her speech (there weren’t any), applauded her warmly, had meetings with her, had their photos taken with her and offered her nothing but praise, while British ministers promised to do more to tackle global warming.

Ten days later, Parliament collectively agreed to declare a “climate emergency”, yet the UK government has not changed tack on energy or climate — it still effectively bans new onshore wind farms in England, provides no financial support for solar projects, plans to increase VAT on solar panels from 5% to 20%; and has reduced subsidies for electric vehicles, which has reduced their take-up.

It has been a similar tale around the world.

Climate protests inspired by Thunberg increased earlier this year, culminating on 15 March, when more than 1.8 million people — mainly children — marched in protest at government inaction in 134 countries around the world. Politicians’ natural instincts were to criticise the protests (which were, after all protesting against government policies).

UK Prime Minister Theresa May said that the children should stay in school so “they can develop into the top scientists, engineers and advocates we need to help tackle this problem”, while German energy minister Peter Altmaier declared: “Skipping school is almost always bad – the more often you do it, the dumber you get.”

But criticising children for seeking a bright future — and for demanding the action scientists say is needed — has not been a good look for any politician, and by mid-March, senior figures were declaring their support for the protests, including German chancellor Angela Merkel and French president Emmanuel Macron.

In April, climate activist group Extinction Rebellion (XR) blockaded central London for ten days, leading to more than 1,000 arrests. And when Thunberg — now an admirable figurehead of the global climate protest movement — arrived in London to support the group’s actions, environment minister Michael Gove told her to her face: “The time to act is now, the challenge could not be clearer — Greta, you have been heard.”

On 2 May, UK energy secretary Greg Clark declared: “In recent weeks people from all walks of life and all sections of society have set out the stark and uncompromising case for further action to protect our planet. I applaud them.

“We know we must do more — and we will do more.”

A week later, eight European countries — France, Belgium, Denmark, Luxembourg, Netherlands, Portugal, Spain, and Sweden — signed a statement advocating for zero greenhouse gas emissions across the EU by 2050 “at the latest”, and calling for the bloc to spend 25% of the EU budget on fighting climate change. With the current EU budget for 2014-20 sitting at more than €900bn (£775bn), a quarter of the forthcoming EU budget could amount to around €250bn.

Increasingly, climate will be hard for politicians to ignore — those that do risk angering voters.

It was noted, however, that the leaders of the other 19 countries in the EU (not including the UK) did not sign up, including the hugely influential Merkel.

“We are in the middle of building a coalition on this,” said French president Emmanuel Macron, when questioned about the lack of support for the plan.

On the same day, the Irish parliament declared a climate and biodiversity emergency, and the media were told that the minister for climate action, Richard Briton, would soon announce new climate-mitigation proposals.

While governments do not seem to have announced any policy changes as a result of the protests, there is little doubt that climate has risen up the political agenda in many countries. Even in the US, where the administration is filled with climate deniers, the issue has become a hot topic, although this is largely due to the Green New Deal proposed by Congresswoman Alexandria Ocasio-Cortez rather than protests. And in Australia, where there will be a general election on Saturday, climate has been a major focus of the campaign.

Like oil tankers, government policies take a long time to turn around, involving discussions with competing factions of ruling political parties, grassroots supporters, coalition partners, civil servants and pollsters.

Increasingly, climate will be hard for politicians to ignore — those that do risk angering voters. And, of course, any efforts to reduce global warming will inevitably involve more wind and solar power.

“Poll after poll confirms that there is a large majority of citizens who recognise that climate change is happening and is man-made,” says Wendel Trio, the director of the Climate Action Network Europe group. “Citizens expect governments to act and reduce our negative impact on the climate. Governments have the obligation to drastically increase emission reductions and protect their citizens from climate disasters.”

Public support for climate action is so great that juries and judges in the UK and the US have been acquitting protesters who have admitted crimes — for example, criminal damage, trespass, disorderly conduct, resisting arrest — on the basis that their actions were necessary due to the threat of climate change, and that the charges are unjust.

In London, the sheer number of protesters causing trouble created difficulties for London’s police force, which had to draft in officers from around the country.

If future protests become larger — which may well be the case, especially if the courts fail to act as a deterrent — it could reach the point where police forces are unwilling or unable to break them up.

Massive, uncontrollable protests have known to bring down governments — just think of Egypt, Tunisia and Ukraine — or changed government policy, such as the withdrawal of the 'poll tax' in the UK in 1990.

“Nothing has changed when it comes to divides and different opinions about [climate action] in the EU,” said European Council President Donald Tusk last week. “What is new is this very fresh and energetic pressure [from young protesters demanding radial action]. There is no future for politicians without this sensitivity and imagination.”