As the Australian election approached, the UK parliament declared a national climate emergency. Perhaps, with a different electoral outcome, Australia would have followed suit. Instead, at least for the next three years, we will ignore the emergency while chasing the mirage of coalmines promising to create thousands of jobs.

That mirage began to fade almost immediately with the announcement that the China Stone project, right next to Adani’s Carmichael mine project in the Galilee Basin, had suspended its bid for mining leases. Other projects in the basin have been on hold for years.

Galilee Basin mine next to Adani put on hold amid doubts over future of thermal coal Read more

The prospects for the Carmichael mine are not much better, at least in the absence of a large injection of public money (which may now be on the cards). Adani announced in November that it would provide $2bn of its own money to fund the project. Gautam Adani could afford to spend this much if he chose to do so, but has so far shown no sign of willingness to pour such a large proportion of his personal wealth into an obvious dud. Such announcements have been made before and nothing has happened.

The coal boom of the last decade will fade away, whatever Australian governments do. By contrast, the climate emergency is not going away and will force itself on our attention sooner or later. When it does, we will face the need to reduce our emissions rapidly and to levels well below the very soft target the current government has set itself.

To match the commitments of comparable countries, Australia would need to cut emissions in 2030 by at least 40% relative to 2005. Moreover, a central point of the Paris agreement in 2015 was recognition that these initial commitments were inadequate and would need to be ratcheted up over subsequent rounds of negotiation. By the time we return our attention to the climate crisis, we will be facing a policy emergency.

Emergencies are costly. Problems that could have been addressed efficiently at low cost over a number of years turn into crises that must be addressed immediately with whatever measures are available. A few examples illustrate the point.

The first step in any serious program of emissions reduction is the transition away from coal-fired electricity generation. If we had implemented Kevin Rudd’s carbon pollution reduction scheme in 2012, or maintained the Gillard government’s carbon price, or even adopted the clean energy target proposed by the Finkel review in 2017 we would, like other developed countries, be on the road to coal-free electricity. The UK, which relied on coal for 50% of its electricity in the early 1990s, introduced emissions trading in 2002, and is now within a few years of eliminating coal-fired power altogether.

As things stand, however, Australia will be faced with the necessity of making the same transition over a period of perhaps five to 10 years. That will entail massive investment in solar PV, storage and wind, totalling perhaps $100bn. Given the uncertain environment created by decades of policy reversals, governments will need either to undertake this investment directly or provide long-term guarantees.

It's easy to dismiss Queenslanders as coal-addicted bogans, but it's more complex than that | Amanda Cahill Read more

At the same time, the existing coal fleet will need to be closed down as rapidly as possible. Any investment in new or refurbished plants financed by the current government will be entirely wasted.

The story is similar with respect to transport. In 2014 the Climate Change Authority (of which I was then a member) proposed a light vehicle fuel-efficiency standards which would have saved motorists money over the life of a vehicle, while substantially reducing emissions. More recently, the emergence of electric vehicles has provided new opportunities for decarbonisation. The current government rejected the fuel-efficiency scheme and has derided electric vehicles – supposedly it might have an electric vehicles policy by mid-2020.

The result of this delay is that when we get serious about the climate emergency, we will have a large fleet of some of the world’s most fuel-inefficient cars, many of them nearly new. The efficient option of providing subsidies for electric vehicles, as Norway has done, will be too slow to achieve the necessary reduction in emissions.

So we will be forced to adopt some form of “cash for clunkers” scheme, in which people are paid to scrap old, inefficient vehicles. This was a terrible idea when it was proposed by Julia Gillard as an alternative to the carbon price she had promised would never be introduced and was promptly scrapped once the 2010 election produced such a price. But by the time we start taking action, it will be one of the few options capable of producing the rapid shift we will need.

Extending this analysis across the economy, it’s clear that emergency measures to reduce emissions will be very costly, compared with the efficient measures we could have adopted with a bipartisan commitment.

That’s the bad news. The good news is that the cost of an emergency response, while large compared with an efficient policy, will be very small in relation to an economy with an annual output, by 2030, of $2tn a year or more. To see this, we can turn to the estimates prepared for the government’s election campaign by Brian Fisher of BAEconomics.

Don’t despair about the climate emergency. Coal is not the future | Frank Jotzo Read more

These worst-case numbers, higher than the costs of the most radical emergency measures, amount to around $50bn a year, or 2.5% to 3% of national income. That’s a lot of money – like adding a new program on the scale of the NBN or the submarine contract every year for five to 10 years.

At the same time, it’s small enough that it would barely be noticed against the background of the general fluctuations in the economy. The average household has lost far more from the wage stagnation of the last decade. As far as the government budget is concerned, the likely impact is comparable to that of increasing health expenditures arising from our increased life expectancy and the development of new treatments.

More importantly, the cost of an emergency response to climate change is trivial compared with the benefits of stabilising the global climate at a level that is livable for humans and the natural environment. We are currently shirking our contribution to this global public good, and free riding on the efforts of others. But sooner or later we will have to pay our share.

• John Quiggin is professor of economics at the University of Queensland. His latest book, Economics in Two Lessons, was recently released by Princeton University Press