The crisis is not imminent. The crisis is here. The recent infernos in Australia; the storms and floods in Brazil, Madagascar, Spain and the US; and the economic collapse in Somalia, caused in part by a devastating cycle of droughts and floods, are not, or not only, a vision of the future. They are signs of a current and escalating catastrophe.

This is why several governments and parliaments, the UK’s among them, have declared a climate emergency. But no one in government acts as if it is real. They operate within the old world of incremental planning for a disaster that has yet to arrive.

Nowhere is this clearer than in the reports of the Committee on Climate Change (CCC), the official body that began with such hope and promise of holding the government to account, but that now seems to have abandoned scientific realities in favour of political priorities.

Its latest report, on changing the UK’s land use, is so unambitious that, in some respects, it would take us backwards. For example, it calls for a 10% reduction in cattle and sheep numbers over the next 30 years. But it admits that over the past 20 years, their numbers have declined by 20%, so this would involve a slowing of the trend. Cultured meat and milk could replace these sectors almost entirely by 2050.

The report makes no mention of rewilding or natural regeneration. The only means it proposes by which trees should return to the land is planting. This is often a slower, more expensive and less effective way of restoring habitats and sucking carbon out of the atmosphere than removing livestock or controlling deer numbers and allowing trees to return by themselves. Its target for reforestation is so feeble that the UK would still have less than half the average current European forest cover by 2050.

One of the reasons for this timidity is its preposterous assumption that if land is unsuitable for commercial forestry, it’s unsuitable for trees. There are plenty of places where trees grow well, store carbon and provide magnificent habitats, but won’t produce straight 50-foot poles. The CCC envisages not wild woods, but plantations, whose purpose is the discredited policy of “bioenergy with carbon capture and storage”.

This means growing wood to burn in power stations, then capturing and burying the carbon emissions. It is likely to cause more harm than good. Could the committee’s enthusiasm have anything to do with the fact that one of its members works for Drax, the energy company pioneering this disastrous technology? Throughout the report, business appears to come first; nature and climate last.

All this, the CCC says, is consistent with the target it has set for the government, of net zero greenhouse gas emissions by 2050. It tells me that the rationale for this target “remains valid today”, meeting the UK’s obligations under the Paris agreement. This agreement commits governments to seek “to limit the temperature increase to 1.5C above pre-industrial levels”.

A firefighter battles the bushfires around the town of Nowra, New South Wales. Photograph: Saeed Khan/AFP via Getty Images

But in November, the UN published a report showing that preventing more than 1.5C meant cutting greenhouse gas emissions by 7.6% every year between now and 2030: a much steeper trajectory than the CCC’s. The committee has set the wrong target, for the wrong date.

But I think the problem runs deeper than this. It’s not just the target that’s wrong, but the very notion of setting targets in an emergency.

When firefighters arrive at a burning building, they don’t set themselves a target of rescuing three of the five inhabitants. They seek – aware that they may not succeed – to rescue everyone they can. Their aim is to maximise the number of lives they save. In the climate emergency, our aim should be to maximise both the reduction of emissions and the drawing down of carbon dioxide already in the atmosphere. There is no safe level of global heating: every increment kills.

Maximisation is implicit in the Paris agreement: it requires governments to pursue “the highest possible ambition”. In its land-use report, the CCC repeatedly admits that it could go further, but insists it doesn’t need to, because its policies will meet the target. The target has supplanted the ultimate objective, which is to respond appropriately to the climate emergency. This is a classic vindication of Goodhart’s law: “When a measure becomes a target, it ceases to be a good measure.”

We are all familiar with the absurdities of target culture. We know how, in many workplaces, the target becomes the task. We know how official targets for depriving people of social security ruined thousands of lives. We know that the Windrush scandal – the persecution and wrongful deportation of people legally entitled to reside in the UK – was caused in part by the Home Office target for “enforced returns”. We know how targets encourage people to game the system, as hospital administrators do with their waiting lists, and cause Kafkaesque nightmares of overzealous officialdom, as David Boyle documents in his new book, Tickbox.

But less discussed is the way in which targets can encourage officials to underperform. As soon as you set a target, you pull back from maximisation. Even if you say “this target is the minimum”, as the CCC does, politicians treat it as merely the line they need to cross. At this point, they fulfil their legal duty, even if they fail to fulfil their wider duty of care.

Is a policy of maximisation possible? It is not only possible, it’s already happening, in exactly the wrong place. The 2015 Infrastructure Act introduced a legal duty to “maximise the economic recovery” of petroleum in the UK. If drilling companies fail to maximise their extraction of fossil fuel from an oilfield, they will be forced to surrender their licence to operate. In other words, while the government observes a legal minimum (the CCC’s target) for reducing greenhouse gases, it observes a legal maximum for increasing them.

The appropriate response to the climate emergency is a legal duty to maximise climate action. The CCC’s board should be disbanded and replaced by people whose mandate is rigorously to explore every economic sector in search of the maximum possible cuts in greenhouse gases, and the maximum possible drawdown. We have arrived at the burning building. The only humane and reasonable aim is to rescue everyone inside.

• George Monbiot is a Guardian columnist