Climate change is becoming hard to ignore. Extreme weather has grown more frequent. Scientists are loudly and urgently sounding the alarm – and people have noticed. The 10-day Extinction Rebellion protests were the biggest act of mass civil disobedience in the UK for generations. The protests, by people drawn from all sections of society, are sure to have a lasting impact. This month has seen the most mentions of climate change in the British media since the landmark Paris agreement in 2015. The country’s political class has been at pains to show it has been moved by the unprecedented outpouring of political feeling. But politicians need to overhaul policy in a far more substantial way than is currently envisaged to stop net emissions of greenhouse gases. The question is not whether this country should achieve a net zero target, but when. Presently the UK is committed in law to reduce greenhouse gas emissions by at least 80% by 2050 compared to 1990 levels. This is not ambitious enough.

Last year’s UN Intergovernmental Panel on Climate Change report suggested that to limit the warming effect to 1.5C, global CO 2 emissions must reach net zero by around 2050. Next week the UK’s Committee on Climate Change is expected to formally recommend the government goes further. Extinction Rebellion (XR) would like the UK to reach zero by 2025. Underlying this ambition is a commendable sentiment but the target is impractical. Britain, as the first country to industrialise and therefore responsible for a large historical stock of carbon dioxide emissions, ought to aspire to reach the UN’s 2050 goal faster, but not as fast as XR demands.

This is not a flight of fancy. The costs of renewable energy have come down, with falls in the costs of wind, solar and batteries that are much bigger and faster than were until recently thought possible. The example of organisations that have set bold decarbonising agendas, such as the National Farmers’ Union, should be applauded and emulated on a national scale. Norway has agreed a net zero goal by 2030; Sweden by 2045. If other modern European societies are willing to accept the costs of transitioning to a greener and sustainable existence, it is hard to see why the UK could not.

It must be acknowledged that having a goal is not the same as meeting one. Projections show the UK will, on its current trajectory, miss its legally binding carbon budgets for 2023-32. The government’s own advisers last year warned that to deliver decarbonisation in the most cost-effective way, even to meet the 80% reduction target, the UK must achieve deeper emissions cuts than those currently set. Putting off difficult decisions will only increase the cost of mitigating and adapting to a decarbonised global economy in the decades to come.

What has been heartening is that the climate protests have been rooted in facts taken from UN reports, official statistics and government papers. The demonstrations worked because their supporters had arguments that resonated and could be easily understood. Whether this translates into votes for XR candidates in European elections will be worth watching. Meanwhile the school strikers have made their own set of uncompromising demands, with a youthful energy that could not be written off. Theirs too is a reasonable reaction to an emergency that politicians are staring at but seem unable to see.

If those in power did not respond to recent protests, they risked losing a generation of voters not prepared to accept a future decided by politicians many of whom will, by the time the scientists’ predictions come true, be dead. Remarkably, with a US president who does not “listen to the science” and disrupts international cooperation on climate change, green activism seems to be gathering momentum and has not only shifted the global discourse but also put pressure on decision-makers to change their policies.