The UN’s Intergovernmental Panel on Climate Change (IPCC) report has driven home just how dangerous the climate crisis is. Faced with this unprecedented and unique challenge, the central question is: can we change course rapidly enough to contain the damage and preserve a halfway liveable planet? If the stark findings of the IPCC were not alarming enough, they are all the more so given the mounting evidence that the impetus for large-scale climate action may be ebbing.

Given the onrushing disaster, we may be forgiven mood swings. Earlier this year, it seemed that the balance of political and economic forces might be swinging in favour of rapid decarbonisation. China, Japan and South Korea had all made net-zero pledges. Trump, the climate-denier-in-chief, had lost the White House. The new Biden administration was pushing what was billed as a major green infrastructure programme. The NextGenerationEU stimulus package was raising ambition. First the Bank of England and then the European Central Bank (ECB) took on the climate issue. The German Green party was riding high in the polls. Investors and financial markets were dumping dirty assets. Even a lobby like the International Energy Agency, once created to represent the interests of oil consumers, was charting a course to net zero. On 14 July, the EU announced its Fit for 55 plan, which implied, among other things, an end to the sale of new internal combustion engine cars by the early 2030s.

That was a high point, but was it also a turning point – in the wrong direction? Horrifyingly, as we digest the IPCC findings, the sense of momentum is flagging. The G7 in Cornwall in June could not agree on an end to coal. The EU and US are at loggerheads over carbon tariffs. The fractious meeting of G20 environment ministers in Naples last month showed how little goodwill there is ahead of the Cop26 summit in November. In the UK, which will preside over the meeting, the Tory party is engaged in bitter infighting over climate. In the US Congress, the climate component of Biden’s infrastructure bill has been reduced to a pale shadow. Meanwhile, as the global economy recovers so too are energy prices, stoking fears of increased fuel costs. In Germany, the Greens have been dogged by agitation around petrol prices. Finally, on Wednesday, in a statement issued from the White House by the national security adviser Jake Sullivan, these tensions exploded into the open.

Sullivan’s statement reads as follows:

“Higher gasoline costs, if left unchecked, risk harming the ongoing global recovery. The price of crude oil has been higher than it was at the end of 2019, before the onset of the pandemic. While Opec+ recently agreed to production increases, these increases will not fully offset previous production cuts that Opec+ imposed during the pandemic until well into 2022. At a critical moment in the global recovery, this is simply not enough. President Biden has made clear that he wants Americans to have access to affordable and reliable energy, including at the pump. Although we are not a party to Opec, the United States will always speak to international partners regarding issues of significance that affect our national economic and security affairs, in public and private.”

Yes, you read that correctly. One of the most senior figures in the Biden administration, the administration that promised climate was “everywhere” in its policy, is declaring that an increase in petrol prices to $3.17 per gallon is a matter of national security and that the US reserves the right to cajole Opec and Russia into flooding the world with more oil.

We should not mince words: if this is the stance of the Biden administration then its decarbonisation agenda has been well and truly buried. According to no less an authority than the IEA, if we are to reach net zero by 2050, we need to end fossil fuel capacity expansion now. In Europe, the likes of Shell are being told by the courts to make plans accordingly. To fill the gap, Saudi Aramco, the world’s largest oil producing company, has let it be known that it is expanding its capacity. Biden’s national security adviser has just given it the green light.

It isn’t only oil markets. Gas prices too are surging and there are calls to expand capacity. There is a power play at work. If politicians get serious about decarbonisation, the oil and gas industry will stop new investments. Since, as things stand, economic activity and fossil fuel consumption are hardwired together, rising demand running up against inelastic supply will produce spikes in prices. Consumers will pay that price and will vent their frustration on politicians. And there is a social justice dimension. Surges in fuel prices hurt low-income consumers most. The Biden administration is committed to a foreign policy for the American “middle class”. On Sullivan’s interpretation, that means pushing the oil oligarchs of Opec and Russia to expand production. It is completely at odds with the IPCC’s message, published only days before.

The US is unique among western powers in having true geopolitical heft. If the EU or Japan squeal, Opec and Russia shrug, which is why this is such a critical test for the Biden administration. If the US is serious about tackling the climate crisis it must use its unique geopolitical leverage not to sustain fossil fuel production, but to curb it.

If prices rise, let that serve notice to affluent consumers that it is overdue for them to shift from giant SUVs to electric vehicles (EVs). To help low-income Americans what is needed is not an Opec production push, but a broad range of measures to ensure that fuel bills do not press so severely on family budgets. That is why Biden’s agenda on jobs, wages, families and the care economy is so crucial. If fuel poverty as such is an issue, adopt targeted relief including, for instance, a national cash-for-clunkers programme, whereby incentives are offered to trade old cars in for new, fuel-efficient ones. Meanwhile, push harder for EV infrastructure and transformative research and development to make low-carbon alternatives affordable for everyone.

The halting progress of Biden’s infrastructure plans and Sullivan’s reactionary oil policy are joined at the hip. Only if the US can set in motion a just transition at home can it credibly lead on climate on the global stage. Until it does, like the fossil-fuel addict that it is, whether governed by Republican or Democrat, it is fundamentally unreliable. Bear that in mind in assessing the scenarios of the IPCC.

• Adam Tooze is a professor of history at Columbia University. His book, Shutdown: How Covid Shook The World’s Economy, is out on 7 September