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https://theconversation.com/how-mainstream-climate-science-endorsed-the-fantasy-of-a-global-warming-time-machine-225597>
"When the Paris agreement on climate change was gavelled into being in December
2015, it briefly looked like that rarest of things: a political victory for
climate activists and delegates from the poorest regions of the world that, due
to colonisation by today’s wealthy nations, have contributed little to the
climate crisis – but stand to suffer its worst ravages.
The world had finally agreed an upper limit for global warming. And in a move
that stunned most experts, it had embraced the stretch target of 1.5°C, the
boundary that small island states, acutely threatened by sea-level rise, had
tirelessly pushed for years.
Or so, at least, it seemed. For soon, the ambitious Paris agreement limit
turned out to be not much of a limit at all. When the Intergovernmental Panel
on Climate Change (or IPCC, the world’s foremost body of climate experts) lent
its authority to the 1.5°C temperature target with its 2018 special report,
something odd transpired.
Nearly all modelled pathways for limiting global heating to 1.5°C above
pre-industrial levels involved temporarily transgressing this target. Each
still arrived back at 1.5°C eventually (the deadline being the random end point
of 2100), but not before first shooting past it.
Scientists responsible for modelling the response of Earth’s climate to
greenhouse gas emissions – primarily caused by burning fossil fuels – called
these “overshoot” scenarios. They became the dominant path along which
mitigating climate change was imagined to proceed, almost as soon as talk of
temperature limits emerged.
De facto, what they said was this: staying below a temperature limit is the
same as first crossing it and then, a few decades hence, using methods of
removing carbon from the atmosphere to dial temperatures back down again.
From some corners of the scientific literature came the assertion that this
was nothing more than fantasy. A new study published in
Nature has now
confirmed this critique. It found that humanity’s ability to restore Earth’s
temperature below 1.5°C of warming, after overshooting it, cannot be
guaranteed. Many impacts of climate change are essentially irreversible. Those
that are might take decades to undo, well beyond the relevant horizon for
climate politics. For policy makers of the future, it matters little that
temperatures might eventually fall back again; the impacts they will need to
plan for are those of the overshoot period itself."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
