Someone writes a memo about his views on gender difference and it kicks off. Apparently women are in tears, too traumatised to go to work. A baker refuses to ice a wedding cake for two guys and my Twitter feed practically bursts into flames. “HOW CAN THIS BE HAPPENING?!”

But mention the climate crisis, something that is smashing temperature records, raising sea levels, driving diseases into places they’ve not been before, and which may lead, as Professor Stephen Hawking suggests, to a need for the human race to flee the planet, and there’s radio silence. You can almost see the digital tumbleweed.

Nearly 30 years after Nasa’s James Hansen testified before a US Senate committee that human activity was warming the planet and must be stopped, it seems the issue does not stir the general population. Partly it’s because of the tens of corporate millions spent by the biggest polluters to create doubt that stalls legislation. That lobbying has worked. Trump said he believes the Chinese made it up, perfectly playing to the right’s paranoia, even as the sand their heads are buried in is getting so hot it would cook an ostrich egg.

But what is surprising is that the left are not more fired up about the climate crisis. In the UK, commentators such as Katie Hopkins imply that the only people who care are hysterical lefty shills. Of course lots of people, on the left and right do care, more than ever. After all, this is an issue of science and survival and we all have the same to lose. But in my experience, many on the left who should care more about climate change just don’t. People who are extremely vocal about homophobia, transphobia, racism and sexism seem to have a blind spot. Which is odd because in the coming decades, all those problems (and more) will be supersized.

Peter Tatchell has long warned that tolerance does not always survive periods of social turbulence. Violent hatred bubbles just under the surface in society. On the day same sex marriage began in the UK, for example, one relatively intelligently argued comment under a newspaper article concluded that what we needed to stop men marrying men and women marrying women was “a civil war”.

Such people are kept at bay – just – by stable societies; by the rule of law; by the fact that the majority of us have a roof over our heads, relative security and three meals a day. But there is plenty of historical evidence to suggest that under stress, civilisation wobbles. Minorities get it harder and sooner. Berlin, infamously, pre-Nazism was a centre of gay freedom. A few years later its gay citizens were in concentration camps. Trump’s transgender military ban comes just six months after the presidency of the most LGBT-friendly commander-in-chief in history.

Does Trump really think trans people shouldn’t serve? Or is he simply cynical and savvy enough to know his base will be appeased, as they always are, by a kick to those on the fringe?

This is not a case of either/or – but for too long, too many progressives have stayed silent over climate change.

People are killed because they are of colour, women, trans, gays or lesbians. These are among the most important issues. But could it be that there are things that we must also raise our voices for, that are more important and on which all other issues rest and rely? The DUP’s position on equal marriage, the BBC gender pay gap, Piers Morgan’s views on non-binary people – all are meaningless if the fight that future generations face is for clean water or surviving wars caused by migration that will make the Syrian crisis, itself partly driven by extreme drought, look like a children’s tea party. We must wake up and take responsibility. This is not a case of either/or – it is possible to campaign on multiple issues at the same time, but for too long, too many progressives have stayed silent over climate change.

We can start to change that by watching Al Gore’s new film An Inconvenient Sequel this weekend. There’s no one left to warn us: scientists and politicians have done so, the Earth itself could not be clearer: this week in Iraq birds are falling from the sky as the country suffers through 50C heat. Spain has just broken its all-time temperature record, hitting a shocking 46C amid a European heatwave named Lucifer. We are on the verge of something literally unimaginable from which scientists say there will be no way back. We have been warned, over and over again. We will only have ourselves to blame.

• Matthew Todd is a former editor of Attitude magazine and the author of Straight Jacket: How to be gay and happy