Shock as warming accelerates, 1.5掳C is breached faster than forecast

February 26, 2024
Issue 
Climate activists blockade the coal port in Newcastle with Rising Tide in November. Photo: Zebedee Parkes

If there was shock and awe recently when the Copernicus Climate Change Service announced that global average warming over the past 12 months 鈥 February 2023 to January 2024 鈥斕齢ad , it was likely because too many people had succumbed to the predominant, but delusional, policy-making narrative that holding warming to 1.5鈥2掳C was still on the cards.

What does this symbolically important moment mean for the poor understanding of climate-risk analysis by Australian governments?

To begin, the idea that emissions could continue till 2050 and still achieve the 1.5鈥2掳C goal was always a con; now it is fully exposed.

One year of 1.5掳C does not constitute a trend, which technically can only be seen in retrospect over 20 to 30 years of data.

But with听 likely in 2024, the rate of warming accelerating and a听current 鈥 which is an indicator of future warming 鈥 it is hard to disagree with the assessment of former NASA climate science chief James Hansen that the world has now reached the 1.5掳C mark for all practical purposes.

When the 2015 global climate conference resulted in the Paris Agreement鈥檚 commitment to hold climate warming to the 1.5鈥2掳C band, those numbers quickly became normalised as the sine qua non of climate policymaking.

But that was a grand illusion on two counts. The听first听was that 1.5掳C was a safe or appropriate target.

Sir David King, a former British Chief Scientist, had collaborated with the small island states in the lead-up to the Paris conference in pushing the 1.5掳C goal. But in 2021, The Independent journalist Donnachadh McCarthy听that King 鈥渁stounded me by saying he now realised this was wrong, and believes the passing of the Arctic tipping point has already been reached 鈥

鈥淗e said the 1.1掳C rise that we already have is too dangerous 鈥 and candidly admitted he believed US climate professor James Hansen had been right after all in 1988, when he warned the US Congress that we should not pass 350 [parts per million] ppm. We have now [in 2021] breached 415 ppm and are heading fast towards 500ppm.鈥

The听second听illusion was that there was any realistic hope of keeping warming to 1.5掳C, or even 2掳C, given the decades of policy-making failure (see image below),听 year after year, the听 which are masking warming, the political inertia rooted in adherence to a slow, economically non-disruptive mitigation path听and, in particular,听state capture by the fossil fuel industry, allowing fossil fuel expansion.

400_image_carboncredits.com_.png

Graph: CarbonCredits.com

Many of us, including some leading scientists,听have been that the world would flash past 2掳C and into the existential 3鈥4掳C range given the failure to treat climate change as the single greatest threat to humanity, and respond accordingly.

But policy-makers focused on the scenarios provided by the Intergovernmental Panel on Climate Change (IPCC), which is charged with presenting policy-relevant science; that is, science for politically-appointed policy makers.

The 2018 IPCC听 said that global temperature was currently rising around 0.2掳C per decade, and 鈥渋f this pace of warming continues, it would reach 1.5掳C around 2040鈥.

The more recent, new generation CMIP6 climate models, using an emissions scenario closest to current circumstances听 1.5掳C between 2026 and 2042, with a median of 2032.

These sets of numbers created a comfort zone for policymakers (鈥渋t could be 20 years away鈥) that are at odds with the reality now unfolding.

Warming rate doubling?

Hansen warned in 2021 that the听rate of global warming over next 25 years that of the previous 50 and, in 2023, he pointed to听 that this acceleration was now happening.

Some were initially sceptical but, as records continue to be smashed month after month, it is now more widely appreciated that the warming rate is at least 50% higher than earlier decades, at 0.3掳C per decade.

Celeste Saulo, the new chief of the World Meteorological Organisation (WMO), said on February 7 that听the rate of , based on research by some WMO science teams. She was concerned, not knowing what it means for the future: 鈥淲e are not there in terms of our scientific understanding of the implications of this acceleration. We don鈥檛 fully understand how it is going to evolve.鈥

That should be a real worry for the Australian government too, in this hottest and driest continent.

That acceleration moves forward the timeline for reaching 2掳C of warming, for the manifestation of more severe impacts and for systemic tipping points.

Hansen warned that warming will accelerate to 1.7掳C by 2030. In comparison, reflected in IPCC reports show temperatures 鈥渁re expected to pass 2掳C in the modest-mitigation SSP2-4.5 scenario 鈥斕齱here emissions remain around current levels 鈥斕齜etween 2038 and 2072, with a median year of 2052.

Advice to the Australian government from the sclerotic Climate Change Authority, reports from CSIRO and the current, domestically-focused, National Climate Risk Assessment (NCRA) all use the IPCC work as the bedrock of their work and advocacy.

This is now a disaster, because warming may be 15 years ahead of the IPCC鈥檚 outdated analysis and its history of reticence on tipping points.

The NCRA is still using a 1.5鈥2掳C by 2050 scenario, Department of Climate Change Deputy Secretary Jo Evans听听Greens Senator Larissa Waters at Senate Estimates on February 12.

鈥淚 don鈥檛 understand why you are doing a risk assessment based on a scenario that鈥檚 so below what鈥檚 actually going to happen. That doesn鈥檛 give you an adequate picture of risk. Isn鈥檛 the whole point of doing this risk analysis to understand what the risks are?鈥 Waters asked.

鈥淲e don鈥檛 think it鈥檚 unrealistic. You are expressing your take on it,鈥 Evans replied.

And that鈥檚 the problem. The government simply isn鈥檛 up to speed, and its risk assessment process is out of time.

Hansen鈥檚 analysis doesn鈥檛 have to be exactly right for his conclusion to be taken very seriously as a plausible worst-case scenario 鈥 though he has not been substantially wrong on any of the big issues in a career spanning 50 years.

Such a scenario should play a prominent role in generating climate advice to governments, because when risks are existential 鈥 as climate minister Chris Bowen has accepted 鈥 it is important to give particular attention to the plausible worst-case or high-end scenarios.

Precautionary action needed

That is where the damage is greatest, and we do not get a 鈥渟econd chance鈥 to learn from our mistakes when a risk is civilisation-ending.

Thus the urgency for precautionary action to ensure these scenarios never occur.

Professor Matt King, head of the Australian Centre for Excellence in Antarctic Science,听said in January he found it embarrassing how little was known about the ocal and global , 鈥渋ncluding a historic drop in floating sea ice cover, the accelerating melting of giant ice sheets and the slowing of a deep ocean current known as the Southern Ocean overturning circulation鈥, which may threaten the viability of some Australian agriculture sectors amongst many adverse impacts.

With warming way ahead of the IPCC view,听 as they reach way outside the model projections, inadequate understanding of听how a is magnifying heat and rain bomb extremes and worries about faster-than-forecast tipping points, including听a that suggests the Atlantic overturning circulation (AMOC) 鈥渋s on tipping course鈥, any government focussed on protecting their people from unexpected and catastrophic impacts would commission an urgent review of this fast-changing landscape.

Bob Berwyn from听Inside Climate听News听 the author of a 2023 AMOC paper, Peter Ditlevsen, as saying that a collapse of the heat-transporting circulation is a going-out-of-business scenario for European agriculture.

Given the way Australia鈥檚 public service has been gutted of climate expertise, the sad state of CSIRO and听the methodological mess into which the 听has fallen, an urgent review would be best led by an independent, eminent scientist, or scientists, who can give analysis and advice free of the turf wars, the silos and the culture of failure so evident within government structures, and of the dead hand of the fossil fuel industry.

It could be a similar role to that played by Ross Garnaut on the economics of climate change.

Some questions the climate minister could reasonably be asked today now include:

1.听What specific advice has the minister received on the magnitude of the warming acceleration and on the implications for impacts and policy-making in Australia over the next 20 years?

2.听Will the scientific inputs to the NCRA听be revised in light of this recognition of accelerated warming and will new modelling be done to accommodate these changed circumstances?

3.听How will the Antarctic changes identified by Matt King be incorporated into the NCRA, especially for food production?

4.听Is the NCRA giving particular attention to a plausible worst-case scenario? In such a scenario, what level of global warming to 2050 would we be looking at?

5.听Chatham House鈥檚 2021 Climate Risk Assessment identifies a high-end scenario as warming of 3.5掳C or more this century. Will the NCRA be specifically looking at such a scenario?

6.听What precautionary action will be taken to head off this looming national climate catastrophe?

Given the performance in Senate Estimates recently, it is not easy to be optimistic about the government鈥檚 response.

[David Spratt is Research Coordinator for the Breakthrough National Centre for Climate Restoration (Naarm/Melbourne). Ian Dunlop was formerly an international oil, gas and coal industry executive and is a member of the Club of Rome and Chair and Executive Committee member of the Australian Security Leaders Climate Group. This article was first published at 听and is reprinted with permission.]

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