“This is just the start,” said Rishi Sunak last week in his climate-wrecking speech from Downing Street. It certainly was just the start, because today, the government has sanctioned drilling in Rosebank, the biggest undeveloped oilfield in the North Sea. This just 14 months after the UK’s hottest day, in July 2022. In that same month, the high court ruled the government’s net zero strategy unlawful, and ministers were ordered to redo their homework. As the flames rise higher and the sirens grow louder, the day could – and should – have marked a genuine sea change in the government’s approach to the climate emergency. Its plan was failing – and the longer it continued to fail, the greater the price we would all pay. But there was no such sea change. In fact, the government doubled down, with a green light for a new coalmine in Cumbria and now approval for Rosebank. Let’s call out this latest act for what it is. Approving this oilfield is morally obscene; it is a climate crime for which the government must be held accountable. Burning Rosebank’s oil and gas would create more CO2 pollution than the combined emissions of 28 low-income countries, home to more than 700 million people,according to the World Bank. This field’s operational emissions alone would exceed the UK’s entire carbon budget allocated to oil and gas production. How does the government justify this climate crime? It will cut energy bills and deliver “energy security” for the British people, ministers claim. Nothing could be further from the truth: 90% of Rosebank’s reserves are in oil but will be “sold on the open market” with the most likely destination being the continent of Europe, according to Equinor, the Oslo-listed company that part-owns the field, thus proving the move is highly unlikely to make the slightest difference to UK energy bills. And when an overreliance on fossil fuels in fact makes us less energy secure, locking ourselves into yet more oil and gas will exacerbate rather than mitigate the problem. How will this climate crime be financed? Ministers will herald “private sector investment” by licensing this field to Equinor. What they might not tell you is that the Treasury is gifting this fossil fuel giant – which recently announced record 2022 global profits of £62bn – a tax break straight from the public purse worth a reported £3.75bn. This giveaway is the result of an egregious loophole in the windfall tax, meaning that for every £100 fossil fuel companies plunge into yet more climate-wrecking oil and gas, they can claim £91.25 back from the Treasury. The chancellor, Jeremy Hunt, had the chutzpah to criticise Joe Biden’s green subsidies when he wrote in the Times that “the long-term solution is not subsidy but security”. Yet he seems to have failed to notice his own government willingly handing out as much as £10bn a year in tax breaks and subsidies for fossil fuel exploration and research. The government always parrots the line, as the climate minister Graham Stuart did when responding to a question of mine in a parliamentary debate earlier this year, that “we cannot switch off fossil fuels overnight”. This false premise fails to distinguish between existing fossil fuel production and new fossil fuel production. No doctor would claim you can phase out a smoking habit of a lifetime immediately. But if you decide you want to give up cigarettes, you stop increasing the quantity you buy – you certainly don’t bulk buy another 30-year supply. The consensus against issuing new fossil fuel licences stretches across the global community and the political spectrum. The International Energy Agency has said just this week that no new coal, oil or gas development should be taking place if we are to stay within the crucial 1.5C limit. The Climate Change Committee’s 2023 Progress Report in June clearly stated that “expansion of fossil fuel production is not in line with net zero”, and that requiring some oil and gas in the years to come “does not in itself justify the development of new North Sea fields”. Even the Tory MP Chris Skidmore argues: “It is simply not possible to achieve our net zero commitments by opening up new oilfields.” Yet the Labour opposition has perversely said it will stand by the decision. The fossil fuel era is over. The US, the EU and others are already starting to embrace a livable future, with a whole suite of abundant and affordable renewable technologies being developed to deliver warm homes and genuine energy security, and to provide long-term, skilled and stable jobs in growing green industries. We need to go much further and much faster; yet this government refuses. It is instead denying climate reality and prioritising its own short-term economic interests over the long-term wellbeing of our children and grandchildren. Today will mark another grave day in our history books unless we take action now to stop it happening. Write to your MP, support #StopRosebank on social media, attend demonstrations – do all you can to let the government and its co-conspiring oil giants know: Rosebank will not happen in our name. Caroline Lucas is the Green MP for Brighton Pavilion