It’s not always easy to recognise a historical tipping point when you see one, but I believe I spotted one when I walked into my local newsagent last Wednesday and saw the front page of the Sun. Over a map of the world which was coloured bright scarlet, the splash headline screamed: “THE WORLD’S ON FIRE”.

Britain’s biggest-selling daily newspaper was not mincing its words. The subheading on the left-hand side proclaimed “PLANET GRIPPED BY KILLER HEATWAVE”, while the right-hand one announced: “HUNDREDS DIE IN EUROPE AND JAPAN”. And if you were wondering what the cause of all this might be, the accompanying news report carried a quote – just the one – from Len Shaffrey, professor of climate science at Reading University, who said: “Global temperatures are increasing due to climate change. The global rise in temperatures means the probability that an extreme heatwave will occur is also increasing.”

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I nearly choked on my KitKat when I read that. Is this really the Sun? The shoutiest outlet belonging to Rupert Murdoch, the media mogul who famously characterised climate change as “alarmist nonsense”? Is something happening here?

I think something is, and I think what the appearance of this front page in a rightwing tabloid signals is that the summer of 2018, which is throwing up extraordinary climactic extremes all over the northern hemisphere, from north Africa to the Arctic, is finally puncturing the bubble of so-called climate scepticism, at least in Britain. Let us at once say that it will take a lot more to puncture that bubble in the United States, where unabashed and brazen denial of the overwhelming scientific evidence for global warming is an article of faith not just with Donald Trump, but with the Republican party as a whole.

But still it’s a start. Because what we are witnessing now is a historic shift in the way that the threat of climate change is perceived by the world, from prediction to observation. Remember: from the first report by the UN’s Intergovernmental Panel on Climate Change in May 1990, the whole argument that global warming is a potentially disastrous danger has been based on the predictions of supercomputer models of the climate system; they were essentially the same computer models that forecast the weather up to six days in advance, but were now being tasked with forecasting the climate up to 100 years into the future. So most of the biggest climate change headlines for the last three decades have been based on prophecy, as it were, from successive IPCC reports calculating that unless we cut our greenhouse gas emissions, global average temperatures will rise by four or even six degrees celsius by 2100, and that sea levels will rise by up to a metre by the same date, and so forth. There have been five IPCC reports, and with each one the computer models have been more refined and the predictions more reliable, so the conclusions are likely to be more robust. Yet the uncertainty of predicting the future remains.

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These predictions have been the scientific strength of the argument for acting to combat the warming to come, but also, its political weakness. The large degree of uncertainty they inevitably contain has provided the soil in which climate denial has sprouted and flourished, after the issue so lamentably became politically polarised between left and right. It has allowed climate action to be characterised by its rightwing opponents merely as an unnecessary and colossally expensive bet about the future, without overwhelming numbers of ordinary people – voters – disagreeing. This is because for the 30 years that ordinary people have been hearing these predictions, they have not seen anything much to worry them when they look out of their windows.

But observation is different. Seeing things happening around you cannot be gainsaid like predictions can, and in this remarkable summer of 2018, events in the real world have been starting to catch up with the climate models’ forecasts of an overheating globe. Not only has Britain sweltered in the five-week heatwave that finally ended last Friday, record-breaking heat has subjected Norway, Sweden and Finland to unheard-of temperatures – above 32C, that’s 90F, recorded 60 miles north of the Arctic Circle. Meanwhile in Ouargla, a Saharan desert city in Algeria, a temperature of 51.3C (124.2F) recorded on 5 July is thought to be the highest ever reliably measured in Africa. And so in Japan, and so in Greece, and so in Canada: all over the northern hemisphere, record-breaking heat.

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The reaction to all this from the Daily Mail last week was very much the traditional and expected take from the rightwing newspaper. It strenuously avoided the term “climate change” as long as it could; on the same day as the Sun, it used the second sentence quoted above from Prof Shaffrey, but not the first one. The next day it could no longer avoid it, by reporting that the Commons environmental audit committee had forecast a trebling of heat-related deaths by 2050. But to set the balance right it wheeled out the reliable climate sceptic Christopher Booker to proclaim, in a truly feeble piece of polemic, that linking climate change to the heatwave was, as the headline put it, “Just Hot Air”.

The Sun also carried an opinion piece from Rod Liddle, which looked at first sight like a climate-sceptic rant, but wasn’t – it was a scolding of the Met Office for nanny-state advice to stay indoors. Last Friday the Sun splashed again on the story with the front-page headline “BAKE TO THE FUTURE” and once more, climate change featured prominently in the news story. It quoted the climate scientist Peter Stott blaming “human-induced climate change” for the increasing global risk of extreme heatwaves. As a sub-headline summarised: “Scorchers could go on for decades say boffins”.

I am fascinated by the Sun’s reaction to these events, so different from the Daily Mail’s, because I think it marks the moment when someone on a rightwing populist newspaper – someone clearly possessed of sharp news antennae – recognises that the time has come when people are finally realising beyond doubt that something abnormal is happening to the global climate. Who knows? Maybe Murdoch will order a different tone to be set in the Sun next week. But I still think it marks a tipping point, when observation begins to replace prediction in the headlines, and the start of a process that will eventually throw the perverted ideology of climate denial into the dustbin of history – where it belongs.

• Michael McCarthy is the author of The Moth Snowstorm: Nature and Joy