Thursday 8 April 2021

Greta Thunberg v the Australian Academy of Science

Or - is 1.5c really out of reach? 
 
The Australian Academy of Science recently released a report on how damaging 3c of global warming would be to Australia's climate. This number wasn't arrived at by accident; it is the projected result of the current global action under the Paris Agreement, even though that agreement claims to target a 1.5c to 2c maximum on warming. 

The report projects the dangers that we can expect from the 3c rise of those business-as-usual emissions pledges - death of the great barrier reef, failure or severely reduced productivity of most Australian agriculture systems, hundreds of thousands of homes lost. These details were, in themselves, newsworthy, but sadly, not unusual.

More alarming, though, it also contained another projection: that it is now "virtually impossible" to limit global warming to 1.5c:
 
"Limiting climate change to 1.5°C is now virtually impossible. A rapid transition to net zero greenhouse gas emissions is required if the international community is to limit warming to “well below 2°C” in line with the Paris Agreement."

This exact claim runs at odds with most established science, and has drawn a lot of consternation from the scientific community and climate activists - even Greta Thunberg has echoed calls not to take the report as a defeat, while scientists have argued against the methodology. 
 
 
Let's examine how the report arrived at the much-discussed projection, and see if the projection is actually substantiated.
 
It starts from the scientific consensus on emissions pathways, as documented in the IPCC Special Report on 1.5c. So far, so good. The red band is what would happen if current climate policies are maintained, orange if the Paris Accord pledges for future action are met - and green is what we actually need to do to guarantee a 1.5c limit to warming and a safe climate:

Page 18

However, the authors then break the timeline down into a carbon budget - putting a number on the amount of greenhouse gases that can still be emitted before that outcome is locked in. And that is where things get a little more anxiety-inducing:

Page 19 - keep in mind this is carbon, not c02e

Based on that IPCC special report, the remaining carbon budget to keep to a 1.5c timeline is 155 gigatons of carbon. The authors have taken that number, subtracted 25 to account for other greenhouse gas emissions, and 70 for carbon cycle feedbacks, to come up with a number of 40 remaining gigatons before we have crossed, irreversibly, beyond 1.5c of warming in the system - by their estimate, around 3-4 years at the present rate before those 155gt have all been emitted.
 
If we actually only have 40gt of current emissions left until 1.5c and our chance of preserving a safe climate is gone, then we really should start to panic - global c02 emissions from energy alone in 2020 were 30.6 Gt, which was "the largest ever" reduction on the prior year. Joy!

But there is a huge problem with those numbers: the 25gt of other gases has already been accounted for in the original 155gt base budget. Even more confusing is the 70gt. It is attributed to the wrong source, and comes from this 2018 paper and its supporting information supplement - but from my reading, the source doesn't say that crossing the line of 1.5c of warming will trigger all of those emissions, and definitely not straight away. The source speaks in terms of estimated impact by 2100, not within a matter of years and thresholds. And it doesn't even mention a 1.5c timeline, let alone estimate carbon cycle feedbacks by 2100 if we keep within 1.5c of warming.
 
In plain language, carbon cycle feedbacks are massive changes, where existing systems reach "tipping points" that mean they permanently change from one state to another, and that this new state will cause further climate change on its own. The classic examples estimated in the report are permafrost melting (releasing frozen methane, accelerating further warming and methane release) and Amazon forest dieback (ending the forest's ability to suck up carbon as it changes into savanna). Perhaps the best-known example of a tipping point is the melting of our Arctic ice sheets, raising sea level massively - and also reducing the amount of sunlight reflected out of the atmosphere and allowing further warming, since dark seawater absorbs more than pure white snow and ice.
 
As you might have guessed from the above, these tipping points are hard to account for accurately, because they can occur as events, not as regular measurable rates of release over time. Most of the numbers that have been estimated, including by the source, are under the RCP2.6 emissions timeline (2c of warming by 2100), and the estimates of carbon released by 2100 are close (112) to the number in the right hand column of table 1. But the column on the left is not supported by the source, or any that I can see.

My thanks to Joeri Rogelj for unpicking some of the confusion over measurements and numbers:

However, there is a bigger conceptual problem. Regardless of where they got it from, the authors add the 70 to our net zero budget is if, as a species, we will hit net zero - and then sit around twiddling our thumbs, waiting for these feedback loops to occur sometime by 2100, while maintaining perfect net zero emissions year after year. But once we have hit net zero greenhouse gas emissions, then we can go the other way, and have net negative emissions, drawing carbon out of the atmosphere.
 
It is entirely possible, *scientifically*, to keep within this budget and to begin drawing down carbon once we have done so so that the feedback events might never occur. The human species could easily start reforesting and afforesting, adopting regenerative agriculture - without even getting into speculative carbon scrubbing technology. We just need plants.
 
And if we are burning up the budget too fast, then we can STOP DOING THINGS. It is within our power to turn off the lights. Before we start shivering in the dark, there are plenty of greenhouse gas emissions consumed by things that do nothing to better humanity, like war games. Or food being left to rot (and emit methane) because farm owners won't pay a living wage. We can start turning private transport into public, convert stationary energy grids to zero-carbon sources. The barriers to doing these things aren't scientific or technical - they are political and economic.
 
For all of the flaws in the numbers, the AAS report asserting that 1.5c of warming is all but confirmed has cut through the muddle of scientific messaging. Take out that 70gt from potential feedback loops, and the 155gt budget is all but gone within 5-10 years anyway - unless we manage to sharply drop our emissions from 2020 levels, today. That's scientifically possible but not going to happen, politically or economically, unless we change the rules of the game.
 
The push back against this report has been, essentially, to find the right scientific messaging to convince the electorate to do something - but no amount of messaging will convince the global capitalist class, who makes most of the decisions about how things are done, that they should stop profiting from their climate-killing investments in fossil fuels, private transport and industrialised agriculture. 
 
Making our cities more bike-friendly is ten times more important than introducing electric cars to reach net zero - but could you imagine the field day the car-obsessed Murdoch press would have with western governments redesigning our cities for bikes? The car barons, oil tycoons and coal-loving billionaires will only be stopped by force. 
 
A lot of scientists interviewed don't want to say true statements like "1.5c is almost impossible" because they think it'll sound too radical and gloomy, even when the scientific probability of keeping within 2c of warming is as low as 5%; but that kind of half-measure rhetoric has been tried and failed. Even the AAS report gives in to this trend, by making ten policy recommendations that stress how profit can be made in the transition, too. We need scientists to tell the truth - that those in control of our economy are sending most of our species over a cliff, because our economy is organised on the basis of profit, not need.
 
What is unspoken in the report's claim that it's now "virtually impossible" to keep to 1.5c isn't the scientific or technological capacity of hitting the targets in time - planting and protecting trees is an art as old as human civilisation, and there are all sorts of proven measures to reduce emissions rapidly, from seaweed in cattle feed to making cities more cycle-friendly - but the impossibility that capitalist decision-making in our economy can be subverted, supplanted or simply gotten rid of within 3-10 years. No capitalist will agree to just stop making a return on investment and let power plants and factories sit idle, even if necessary for the preservation of our safe climate, while we all go out and plant trees.
 
But that is what must be done.
 
If we want to preserve the relatively safe climate which has nurtured all of our recorded history, then we need to fight against capitalist control of our economy. The AAS report reveals the obvious but unspoken truth of climate politics - that so long as capitalists are generating profit from carbon-emitting economic activities, carbon will keep being emitted and our safe climate will keep on being destroyed.
 
And, by claiming that it is still "possible" to keep to 1.5c of warming and a safe climate, Greta Thunberg and the scientists are, in fact, pushing back against challenging that assumption. They don't want to question rules of the game. But as the AAS and other climate scientists have clearly demonstrated, pledges under the Paris Accords and the status quo of incremental market mechanisms are not going to preserve our safe climate, not even come close. The 1.5c game is being lost, and climate activists need to question why the referees are blowing the whistle on meaningful changes, not just try again for 1.6c on the same rigged field with the same rigged rules.
 
It's time to forget about market-based solutions to climate change. It's time to take carbon off the market. 
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1 comment:

  1. GJOESQ10/04/2021, 10:05

    I couldn't agree more. Our neoliberal political leaders are fools and must be removed at the next Federal election. No more market solutions!

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