The only worthwhile 2030 political emissions reduction target is the Greens’ 75 per cent, which is more or less impossible.

So the main task of government from here should be to prepare the country for the effects of global warming.

Doing something to try to prevent it is important, but secondary.

In 2009, the then Department of Climate Change prepared a “first pass” assessment of the risks to Australia’s coasts, which was the only thing the government has ever produced about climate change risks.

It needs to be updated and extended to all risks, so we all know what we’re going to be in for.

Whenever the Greens’ target is mentioned, it’s dismissed as “extreme” and “radical”, and when lined up against the LNP’s 26 to 28 per cent, Labor’s 43 per cent and everybody else’s 50 per cent, it does look to be both of those things.

The trouble is that these political targets have nothing to do with science, and it’s clear that politics – both democratic and autocratic – is incapable of dealing effectively with climate change.

As Labor climate change spokesman Chris Bowen put it at the National Press Club: “Our target of 43 per cent emissions reductions over the years to 2030 is ambitious and achievable.”

By which he means it looks relatively ambitious and is politically achievable. Why 43? Because it sounds better than 26 to 28, a bit less ambitious than their previous 45, and more achievable than 50 or, God forbid, 75.

The problem with all of these numbers is that greenhouse gases, both carbon dioxide and methane, stay in the atmosphere, so the best way to look at emissions is cumulative, not year by year, since they accumulate.

Led by Adam Bandt, the Greens have an emissions reduction target of 75 per cent by 2030. Photo: AAP

Our carbon budget

The annual emissions targets everybody is arguing about are just a way of achieving a cumulative number that might be consistent with preserving our way of life.

So far, 1.6 trillion tonnes of carbon dioxide have been put into the atmosphere since 1751, which has warmed the planet by an average of about 1 degree centigrade above the average temperature of 1850 to 1900. It’s all still there.

The Intergovernmental Panel on Climate Change (IPCC) has produced a range of possible budgets to keep further warming to 1.5 and 2 degrees from here.

For a 50 per cent chance of 2 degrees, it’s 1350 gigatonnes (billion tonnes) of carbon dioxide; for 67 per cent it’s 1150 GtCO2; and for 83 per cent it’s 900 GtCO2.

For a 50 per cent chance of 1.5 degrees, it’s 500GtCO2; for 67 per cent it’s 400; and for an 83 per cent chance it’s 300.

It’s a wide range with a variety of probabilities for us to choose from, but to keep it simple for policymakers they came up with a “net zero by 2050” target to aim at after the Paris meeting in 2015, in line with the 67 per cent probability of 2 degrees of warming.

By the way, an outfit called the Mercator Research Institute on Global Commons and Climate Change has a fairly frightening clock ticking down for both 2 degrees and 1.5 degrees, showing 1071 and 321 GtCO2 to go, respectively.

Catastrophic warming

In Glasgow this year, the thinking shifted from 2 degrees to 1.5 degrees because it’s felt that 2 degrees would still be catastrophic.

The current 1 degree of warming is bad enough, and the frequency of extreme weather is not a linear progression with the increase in temperature: The difference between 1 and 1.5 degrees is greater than 50 per cent.

The general 2050 net-zero target was unchanged in Glasgow, but the focus shifted to 2030 so that the task in the next 20 years wouldn’t be too great.

So everybody agreed to come back next year with a more ambitious target for 2030; the Australia government signed that, but then said it wouldn’t deliver a higher target.

It’s also likely that the focus will now shift to carbon budgets rather than annual emissions.

The last official government estimate of Australia’s share of the global budget was published by the Climate Change Authority (CCA) in 2014 – before the Clean Energy Act was repealed in July that year and any further calculations were shut down (while keeping the CCA barely alive).

According to the CCA then, Australia’s carbon emissions budget for 2 degrees of warming for the period 2013 to 2050 was 10.1 million tonnes. It’s probably a bit more now.

The way we’re going, it will be spent by 2033, not 2050.

This year a group called the Climate Targets Panel, brought together by former Liberal Party leader John Hewson, updated Australia’s budget for 1.5 degrees of warming, from 2021.

It’s 3.5 billion tonnes, and will be spent by 2028 at the current rate of 498.9 million tonnes per year (reported by the Department of Industry’s in its latest National Greenhouse Gas Inventory for June 2021).

To keep global warming to 1.5 degrees, and therefore a budget of 3.5 million tonnes, Australia’s emissions would have to be cut by about 75 per cent by 2030, or to 125 million tonnes, which is the reason for the Greens’ target.

But is that even possible?

Basically, it would require all coal-fired electricity generation to be shut down over the next two or three years and replaced with solar, wind and batteries and most transport and household heating and cooking to switch to electricity, away from gas, very quickly indeed.

It may be theoretically possible, but would cost the government a multiple of Labor’s $24 billion Powering Australia plan for a 43 per cent emissions reduction by 2030.

That means the real problem for Australia in combating climate change is that the budget deficit to be revealed next week is about $100 billion and government debt is more than $850 billion because of the pandemic.

The latest IPCC report said bushfires would become more intense and frequent. Photo: AAP

When politics fails

The spending and sacrifice required for 1.5 degrees is politically impossible, and 2 degrees is close to impossible.

Something similar applies globally.

Governments everywhere are mired in debt while pledging to cut emissions to net zero by between 2030 and 2060, mostly 2050.

Some, like Europe, are using emissions trading schemes to force the private sector to pay for it, while others, like Australia, are planning to use taxpayers’ money.

But the average global carbon price of about $4.50 per tonne is way too low to have any serious impact, and most government spending proposals are hopelessly inadequate for the simple reason that the pandemic has emptied the coffers (unless governments around the world have an unlikely conversion to Modern Monetary Theory).

Ross Garnaut devoted a chapter of his 2008 Climate Change Review to adaptation, starting with these words: “Mitigation will come too late to avoid substantial damage from climate change.

“Some may expect that government can, and should, protect the community from climate change by implementing the right strategy, program or initiative to allow Australians to maintain established lifestyles. This is not a realistic expectation …”

I remember thinking at the time that this was a big statement.

Since then, there has been nothing from government about what to expect, apart from that “first pass” on the coastal impact from the Department of Climate Change and endless optimism about how we’re meeting and beating our targets and everything will therefore be OK.

As Garnaut wrote 13 years ago: This is not a realistic expectation.

Alan Kohler writes twice a week for The New Daily. He is also editor in chief of Eureka Report and finance presenter on ABC news