First came the plague, then the flood, and now the fire. This has been a biblical summer, one where the doomsday warnings of climate scientists have felt increasingly close to the bone.

Horror stories of Chinese commuters drowning as underground train tunnels suddenly filled with water have merged uncomfortably in our imaginations with images of flash floods in east London, wildfires burning up the Turkish coast and a Canadian heatwave so fierce it cooked mussels in their shells on the beach.

So, with the crucial Cop26 climate change summit due to be held in Glasgow this autumn, why not seize the moment? Climate deniers, including those on the Tory backbenches, are on the back foot. New electric car registrations are up, as wealthier households emerge from the pandemic with savings to spend: that pent-up consumer boom that the chancellor, Rishi Sunak, is counting on could easily be steered in a green direction as millions begin to recognise that we should do something to change our lifestyles but aren’t quite sure what.

Are cars the priority, or getting rid of your gas boiler, or flying less, or something to do with diet? These are big decisions, the kind many people can’t afford to make without help from the state. Even the comfortably off won’t be confident enough to make them without reassurance from government that change really is now unavoidable, and clear guidance on how exactly to go about it.

But, puzzlingly, in an interview last week, all the prime minister’s new climate spokesperson, Allegra Stratton, had to offer was tips on freezing bread rather than letting it go stale and not rinsing plates before putting them in the dishwasher – plus the eyebrow-raising confession that she personally “doesn’t fancy” an electric car because stopping to charge it on long journeys might be a pain. (Never mind that, as numerous experts promptly pointed out, most new models have a range of 200 miles.)

Just when we most need clarity, what we get is two contradictory messages fighting for a confused public’s attention: one that this is a global emergency demanding we move further and faster to net zero, and the other that we’ve got all the time in the world to play around with baby steps like freezing your leftovers.

Blaming the messenger, who only took the Cop26 brief when the job she was actually hired to do for Downing Street was axed at the last minute, is easy. But the bigger problem is the gaping holes in the message.

To change behaviour, first be clear and consistent about what you want people to do, especially if it’s not something that comes naturally. That’s a lesson ministers should have learned from a year of publicly contradicting each other over Covid – to the point where even the most well-intentioned now struggle to understand whether the government wants them to go back to the office, fly to Spain, wear a mask, or none of the above. Climate-change messaging is descending into much the same muddle, and that suggests a more structural weakness at the heart of government.

This week a report from the Institute for Government, a thinktank with deep connections in Whitehall, ripped into the government’s strategy for handling Covid in schools, suggesting education ministers were caught short – with no backup plan for cancelling exams, in part because of pressure from the top not to prepare for the worst. A No 10 source told the report’s authors that there was a “clear steer” from the prime minister against making contingency plans because “if you prepare for these things not happening then the outcome is that they are far more likely to not happen … people will look for the easy way out”.

The idea seems to have been that if there was no safety net, everyone would jolly well have to make a go of the tightrope. Yet the tightrope still snapped, which is why it’s worrying that the clearest signal now emerging from No 10 on a range of climate-related policies is that industry will work something out; that once their backs are sufficiently against the wall, businesses will simply innovate their way out of the fact that heat pumps are prohibitively expensive replacements for gas boilers, or that millions can’t actually afford new electric cars.

It’s true that the cost of green technologies is likely to come down once they’re produced at greater scale. But the idea that tech alone can be compelled to save us is not a cast-iron strategy so much as an attempt to shape the world by positive thinking. Meanwhile, a detailed strategy for Britons to wean themselves off gas central heating – which was supposed to have been published already and would have given Stratton something concrete to talk about – has been reportedly held up by tensions between No 10 and No 11 over how to pay for it all.

What we’re seeing on the climate crisis looks, in other words, wearily familiar: a combination of Boris Johnson’s allergy to taking unpopular decisions, plus a preference for working in what his old consigliere Dominic Cummings calls an atmosphere of chaos, where nobody is entirely sure what their mercurial boss wants or stands for, and thus finds it harder to oppose him. Global emergency, meet political mindset spectacularly ill-equipped to deal with one. Haven’t we learned by now how this movie ends?

• Gaby Hinsliff is a Guardian columnist