2015 saw attempts to airbrush sensitivity out of the climate conversation, as folks like Micheal Tobis and the gentleman running And Then There’s Physics argued that we should move on. They (perhaps naturally, given their conviction that climate change is so catastrophic that ‘the survival of the f**king planet is at stake’) just want their assumptions of a high sensitivity accepted.
They want to replace sensitivity-based calculations with things like Representative Concentration Pathways (RCPs), which started out innocently enough as inputs to climate models with the end points given as a starting assumption but were then hijacked to become ‘predictions, projections and/or scenarios.’ All with another assumption embedded–high sensitivity.
We also saw the introduction of a new target for temperature. We’re now supposed to aim for 1.5C above pre-industrial levels, rather than 2C. I suppose I shouldn’t complain–the 2C target was admittedly grabbed out of thin air, not based on science. Why not 1.5C instead? Of course, given that we’ve already achieved 1C above pre-industrial levels, it’ll take some doing, but if you’re just making stuff up, why not?
Now And Then There’s Physics has a new post up on Zero Emissions. It was apparently prompted by a post from David Roberts, perhaps best known for calling for Nuremberg Trials for ‘deniers.’
ATTP writes, “The zero refers to net global emissions, not to temperature. The argument is essentially that
zero is a much more compelling and evocative goal than the longer-standing and better-established climate goal of limiting temperature rise to 2 degrees or less.
And then ATTP writes one of the strangest sentences I have seen in the climate conversation:
“David Roberts is, of course, quite correct that if we want to stabilise temperatures we’ll have to aim to get emissions to zero. If this could be accepted and focused on, it may well be more effective than having some kind of warming target.”
Stabilize temperatures? Does ATTP think temperatures were stable before humans began emitting CO2? Does he think that if we actually ceased emissions temperatures would no longer change?
Zero emissions is not possible now, of course. I would argue that it will never be possible. I would further argue that it is not strictly necessary, that the IPCC doesn’t call for it and that the world we would see with zero emissions would be without doubt worse than a world with 1.5C, 2C, 4C or 6C higher temperatures. We would have to abandon air travel, cement, ocean shipping–and even barbecues. No thank you.
It’s a pity, because ATTP ends his post with something that makes common sense. It’s something I’ve been writing for most of a decade, but I’ll forgive ATTP for not properly attributing it.
It’s based on conversations Paul Kelly and I used to have over at Bart Verheggen’s weblog. I would frequently write that the initial steps we need to take to combat global warming of 4C are exactly the same as those we would take to fight global warming of 2C. (The steps I advocate are found here.)
ATTP rephrases it as “These debates are moot, however, as the decisions that need to be taken now to limit warming to 1.5 or 2 °C are very similar. We need to agree how to start, not where to end mitigation.”
When he’s right, he’s right. You’re welcome, ATTP.
Note: ATTP and I have banned each other from commenting on our respective sites. As I have mentioned him here, he is welcome to comment on this thread should he wish to.