The sheer scale of the bushfires sweeping through south-east Australia, turning the sky first black, then a terrifying apocalyptic red, defies the imagination. About 5.5m hectares of land has been burned; an area larger than Denmark and the Netherlands put together. This bushfire season began in the Australian spring and the blazes spread far and wide. The vast volume of dust and ash generated has turned the glaciers and snow-capped mountains of New Zealand’s South Island brown.

The signs of new and dangerous times are unmistakable. With another wave of unbearable heat expected this weekend, the biggest-ever population exodus is under way from New South Wales, where residents have been told their homes will be “undefendable” in the days to come. In neighbouring Victoria, a state of disaster has been announced, permitting formal evacuation orders to be issued. The army and navy have been deployed to transport residents from affected areas, at risk of further devastation with temperatures forecast to reach the mid-40s celsius by Saturday. The trail of destruction, which has so far led to the loss of 18 lives, has been facilitated by a combination of searing heat, strong winds and a record-breaking three years of drought, which left soil moisture at historic lows.

This is a national catastrophe. It must be hoped that the courage, skill and fortitude of local residents, emergency services and the armed forces can mitigate the ongoing disaster. With most of the summer still to come, it will almost certainly be many weeks before the worst is over. But when respite comes, so will a mighty reckoning for Australia’s prime minister, Scott Morrison, and his Liberal-led coalition government.

That rising temperatures, linked to greenhouse gas emissions, have turned swathes of Australian territory into a vulnerable tinderbox is incontestable. Last year, the former commissioner of the NSW Fire and Rescue department wrote to Mr Morrison, warning of the impact of the climate crisis on Australia. But as this tragedy has unfolded, one of Mr Morrison’s main concerns has been to deflect and distract from this obvious truth. Having initially been reluctant to cut short his Christmas holiday in Hawaii to deal with the emergency, Mr Morrison denied any “direct” link between the fires and global climate change. He then used a video address on New Year’s Eve to assert that previous generations had “also faced natural disasters, floods, fires, global conflicts, disease and drought”. In October Mr Morrison’s deputy, Michael McCormack, mocked critics who linked the fires to the climate crisis as “inner-city raving lunatics”.

Mr Morrison claims his government, which was elected in May, has a mandate to prioritise the needs of business over exemplary action to cut carbon emissions. Australia has one of the highest levels of per capita CO 2 emissions in the world and is unlikely to meet its highly modest reduction target of 26% to 28% by 2030. The prime minister has pledged to maintain Australia’s position as a world-leading coal exporter. The country’s energy minister, Angus Taylor, has suggested that countries like Australia cannot single-handedly have a meaningful impact on global emissions when countries such as China and India fail to follow suit.

That is a counsel of despair. It is also one that is culpably inadequate, coming from a minister whose country is getting hotter, dryer and more dangerous as each year goes by. Mr Morrison might look to the past for morale-boosting inspiration. But the crisis unfolding on his watch is unprecedented. His reckless disregard for the principal cause must cease.