It is not only Donald Trump’s government that censors the discussion of climate change; it is the entire body of polite opinion. This is why, though the links are clear and obvious, most reports on Hurricane Harvey have made no mention of the human contribution to it.

In 2016 the US elected a president who believes that human-driven global warming is a hoax. It was the hottest year on record, in which the US was hammered by a series of climate-related disasters. Yet the total combined coverage for the entire year on the evening and Sunday news programmes on ABC, CBS, NBC and Fox News amounted to 50 minutes. Our greatest predicament, the issue that will define our lives, has been blotted from the public’s mind.

Quick guide Tropical storm Harvey and climate change Show Hide Is there a link between the storm and climate change? Almost certainly, according to a statement issued by the World Meteorological Organization on Tuesday. “Climate change means that when we do have an event like Harvey, the rainfall amounts are likely to be higher than they would have been otherwise,” the UN organisation’s spokeswoman Clare Nullis told a conference. Nobody is arguing that climate change caused the storm, but it is likely to have made it much worse. How did it make it worse? Warmer seas evaporate more quickly. Warmer air holds more water vapour. So, as temperatures rise around the world, the skies store more moisture and dump it more intensely. The US National Weather Service has had to introduce a new colour on its graphs to deal with the volume of precipitation. Harvey surpassed the previous US record for rainfall from a tropical system, as 49.2 inches was recorded at Mary’s Creek at Winding Road in Southeast Houston, at 9.20am on Tuesday. Is this speculation or science? There is a proven link – known as the Clausius-Clapeyron equation – that shows that for every half a degree celsius in warming, there is about a 3% increase in atmospheric moisture content. This was a factor in Texas. The surface temperature in the Gulf of Mexico is currently more than half a degree celsius higher than the recent late summer average, which is in turn more than half a degree higher than 30 years ago, according to Michael Mannof Penn State University. As a result there was more potential for a deluge. Are there other links between Harvey and climate change? Yes, the storm surge was greater because sea levels have risen 20cm as a result of more than 100 years of human-related global warming. This has melted glaciers and thermally expanded the volume of seawater.



This is not an accident. But nor (with the exception of Fox News) is it likely to be a matter of policy. It reflects a deeply ingrained and scarcely conscious self-censorship. Reporters and editors ignore the subject because they have an instinct for avoiding trouble. To talk about climate breakdown (which in my view is a better term than the curiously bland labels we attach to this crisis) is to question not only Trump, not only current environmental policy, not only current economic policy – but the entire political and economic system.

It is to expose a programme that relies on robbing the future to fuel the present, that demands perpetual growth on a finite planet. It is to challenge the very basis of capitalism; to inform us that our lives are dominated by a system that cannot be sustained – a system that is destined, if it is not replaced, to destroy everything.

To claim there is no link between climate breakdown and the severity of Hurricane Harvey is like claiming there is no link between the warm summer we have experienced and the end of the last ice age. Every aspect of our weather is affected by the fact that global temperatures rose by about 4C between the ice age and the 19th century. And every aspect of our weather is affected by the 1C of global warming caused by human activities. While no weather event can be blamed solely on human-driven warming, none is unaffected by it.

We know that the severity and impact of hurricanes on coastal cities is exacerbated by at least two factors: higher sea levels, caused primarily by the thermal expansion of seawater; and greater storm intensity, caused by higher sea temperatures and the ability of warm air to hold more water than cold air.

Before it reached the Gulf of Mexico, Harvey had been demoted from a tropical storm to a tropical wave. But as it reached the Gulf, where temperatures this month have been far above average, it was upgraded first to a tropical depression, then to a category one hurricane. It might have been expected to weaken as it approached the coast, as hurricanes churn the sea, bringing cooler waters to the surface. But the water it brought up from 100 metres and more was also unusually warm. By the time it reached land, Harvey had intensified to a category four hurricane.

We were warned about this. In June, for instance, Robert Kopp, a professor of Earth sciences, predicted: “In the absence of major efforts to reduce emissions and strengthen resilience, the Gulf Coast will take a massive hit. Its exposure to sea-level rise – made worse by potentially stronger hurricanes – poses a major risk to its communities.”

To raise this issue, I’ve been told on social media, is to politicise Hurricane Harvey. It is an insult to the victims and a distraction from their urgent need. The proper time to discuss it is when people have rebuilt their homes, and scientists have been able to conduct an analysis of just how great the contribution from climate breakdown might have been. In other words, talk about it only when it’s out of the news. When researchers determined, nine years on, that human activity had made a significant contribution to Hurricane Katrina, the information scarcely registered.

I believe it is the silence that’s political. To report the storm as if it were an entirely natural phenomenon, like last week’s eclipse of the sun, is to take a position. By failing to make the obvious link and talk about climate breakdown, media organisations ensure our greatest challenge goes unanswered. They help push the world towards catastrophe.

Hurricane Harvey offers a glimpse of a likely global future; a future whose average temperatures are as different from ours as ours are from those of the last ice age. It is a future in which emergency becomes the norm, and no state has the capacity to respond. It is a future in which, as a paper in the journal Environmental Research Letters notes, disasters like Houston’s occur in some cities several times a year. It is a future that, for people in countries such as Bangladesh, has already arrived, almost unremarked on by the rich world’s media. It is the act of not talking that makes this nightmare likely to materialise.

Play Video 2:44 Tropical storm Harvey: the story so far – video report

In Texas, the connection could scarcely be more apparent. The storm ripped through the oil fields, forcing rigs and refineries to shut down, including those owned by some of the 25 companies that have produced more than half the greenhouse gas emissions humans have released since the start of the Industrial Revolution. Hurricane Harvey has devastated a place in which climate breakdown is generated, and in which the policies that prevent it from being addressed are formulated.

Like Trump, who denies human-driven global warming but who wants to build a wall around his golf resort in Ireland to protect it from the rising seas, these companies, some of which have spent millions sponsoring climate deniers, have progressively raised the height of their platforms in the Gulf of Mexico, in response to warnings about higher seas and stronger storms. They have grown from 40ft above sea level in 1940, to 70ft in the 1990s, to 91ft today.

This is not, however, a story of mortal justice. In Houston, as everywhere else, it is generally the poorer communities, least responsible for the problem, who are hit first and hit worst. But the connection between cause and effect should appeal to even the slowest minds.

It's a fact: climate change made Hurricane Harvey more deadly | Michael E Mann Read more

The problem is not confined to the US. Across the world, the issue that hangs over every aspect of our lives is marginalised, except on the rare occasions where world leaders gather to discuss it in sombre tones (then sombrely agree to do almost nothing), whereupon the instinct to follow the machinations of power overrides the instinct to avoid a troubling subject. When they do cover the issue, they tend to mangle it.

In the UK, the BBC this month again invited the climate-change denier Nigel Lawson on to the Today programme, in the mistaken belief that impartiality requires a balance between correct facts and false ones. The broadcaster seldom makes such a mess of other topics, because it takes them more seriously.

When Trump’s enforcers instruct officials and scientists to purge any mention of climate change from their publications, we are scandalised. But when the media does it, without the need for a memo, we let it pass. This censorship is invisible even to the perpetrators, woven into the fabric of organisations that are constitutionally destined to leave the major questions of our times unasked. To acknowledge this issue is to challenge everything. To challenge everything is to become an outcast.

• George Monbiot is a Guardian columnist