Scientists prize neutrality – that doesn’t cut it any more. In 2025, they must fully back the climate movement | Bill McGuire and Roger Hallam

10 hours ago 3

The past 12 months have seen our world enter new territory. Last year will go down as the first time that the global average temperature exceeded 1.5C above preindustrial times over a calendar year. We could crash permanently through the 1.5C guardrail within the next five years, and shatter the 2C limit as soon as 2034. This will almost certainly result in the tipping points for collapse of the Greenland and west Antarctic ice sheets being crossed, committing us to the drowning of coastal towns and cities.

In years to come, we will look back at this time and ask the same question that future generations will ask: why didn’t we stop this catastrophe?

Meanwhile, the crackdown on those fighting to stop it began in earnest last year. One of us is locked up for five years alongside other peaceful citizens, simply for organising protests to block a motorway. The other was not allowed to provide supportive expert testimony about the potential damage of climate breakdown during the court case. Both were brazen attempts to stamp down on free speech and stymie action.

Hopes that a Labour government would mean a new broom have quickly been dampened, as green pledges have been watered down or dumped. The prime minister, Keir Starmer, has condemned activists as “pathetic” and needing to “feel the full force of the law”.

As a campaigner and a climate scientist, we have come together to say this to you: we are heartbroken, we are devastated, but most of all we are absolutely furious that our political class and our judiciary are betraying our country, and the lives and livelihoods of our children and many generations still to come. The establishment and vested interests around the world have closed ranks to shut down voices seeking to tell the truth about our dire predicament.

But we are not done yet. We need to make 2025 the year that scientists, activists and all who care about the future of our planet mobilise together, to demand that our leaders, and governments around the world, treat climate breakdown as the desperate emergency it is, and act accordingly to slash emissions as the science demands – by at least 45% (compared with 2010) by 2030.

It is absolutely critical, too, that scientists are in the vanguard. Some are already doing their bit, but far too many remain silent on the greatest ever threat to human civilisation. This has to change. There are nearly 9 million scientists in the world, making up a tribe that is one of the most trusted groups on the planet. Imagine the noise they could make if they spoke with one voice; think of the impetus it would give climate activism. The UK courts have tried to silence climate scientists in the past few years, by keeping their expert testimony out of court cases. As we start out on the second quarter of the 21st century, let’s show them what we can really do.

Inevitably, there are those who demand impartiality from scientists, but being impartial doesn’t mean not telling the truth; it doesn’t mean playing down threats; and it certainly doesn’t mean keeping silent at a time of global emergency. Wanting to remain apolitical no longer cuts it. It is naive at the best of times, but this is now a matter of survival, not politics. So, throw your weight behind those groups and organisations fighting to tackle climate breakdown, work to bring colleagues on board, and use your influence in the best way you can to drive serious action. As we have said before, there are no grant-awarding committees on a dead planet, so it is time to choose which side of history you are on.

Speak, write, shout from the rooftops. Do whatever needs to be done to maximise the number of people who hear the reality of what is happening to our rapidly faltering climate. Make politicians listen. Make business sit up and really take notice. If it scares people, so be it. As scientists – more than others – are aware, what is coming is truly horrifying. And we won’t address the issues in the way we need to until everyone understands the full extent of the threat. The voices of 9 million science heavyweights adding clout to those of countless activists cannot fail to galvanise the public, driving citizen climate action as never before. Together, we can ensure that no space is left unoccupied, that there is nowhere to turn to avoid our message. The only way to shut us up will be to finally do what needs to be done.

This means slashing emissions – not at a rate that doesn’t reach net zero in another quarter of a century, but that reaches real zero as soon as possible. It means widespread and deep adaptation to the world-shattering changes that are now inevitable. Already, a return to a prehistoric climate is impossible to dodge. We have pretty much regressed 125,000 years to the heat of the last interglacial period, and a return to a steamy Pliocene climate (3m years ago) beckons as soon as the 2030s.

This year is certain to be the grimmest so far of the climate emergency, with a climate-breakdown denier in the White House, fossil fuel companies seeking to expand operations, and supercharged extreme weather set to take an even greater toll. We can’t hold back. The brutal truth is that the planet’s temperature is climbing faster than at any time in the geological record. We have a world to save, even if it doesn’t want to be.