The plan becomes the problem if/when the so-called overshoot never comes back. Advocating the end of fossil fuels as the only hope is futile without a vanishingly unlikely global economic agreement, which would create worse problems than anything the IPCC climate alarm team can conjure up on its models. The authors here insist that ‘Avoiding climate breakdown demands that we bury the fantasy of overshoot-and-return’. But climate fantasies are rife.
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Summary: Surpassing 1.5°C of warming can be undone at a later date – using tech, land and resources that don’t exist.
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, says The Conversation.
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.
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The findings of this new paper make it perfectly clear: There is no time machine waiting in the wings. Once 1.5°C lies behind us, we must consider that threshold permanently broken.
Full article here.
via Tallbloke’s Talkshop
October 10, 2024 at 07:41AM
Iowa Climate Science Education 