ATTP started it by posting on Well below 2 °C: Mitigation strategies for avoiding dangerous to catastrophic climate changes by Yangyang Xua and Veerabhadran Ramanathan. But as you can tell from ATTP's post, the principal question - although he is far too polite to put it so bluntly - is "where's the novelty?"1 All their GHG and temperature scenarios, as they themselves stress, are consistent with IPCC; so there's nothing new there. Neither are the stochastic runs and attempts to assess the probabilities of exceeding various thresholds. Neither, alas, are the attaching of arbitrary labels to arbitrary temperature thresholds, although this is without doubt the bit that will interest the meeja.
FWIW, I think that 3oC GW is certainly "dangerous", though I'd be hard pressed to assign a clear meaning to the term.
I could try reading their PR which confirms my suspicions: A new study evaluating models of future climate scenarios has led to the creation of the new risk categories “catastrophic” and “unknown” to characterize the range of threats posed by rapid global warming. I think that really does mean tht the labels are the novelty. They continue, Researchers propose that unknown risks imply existential threats to the survival of humanity which is either meaningless or vacuous, I can't quite tell which.
While I'm here, I'll quote Climate risks can vary markedly depending on the socioeconomic status and culture of the population... the poorest 3 billion people living mostly in tropical rural areas, who are still relying on 18th-century technologies for meeting basic needs such as cooking and heating... mostly subsistent farmers, whose livelihood will be severely impacted, if not destroyed, with a one- to five-year megadrought, heat waves, or heavy floods... But the article errs, I think, in not considering possible changes to this population. Certainly the proportion, and absolute number, of people living in absolute poverty has decreased over the last 50 or 100 years, and can be expected to continue to decrease, especially or almost entirely if their governance improves; see-also Harvey. That doesn't help the ecosystems, of course. But the West has entirely removed the class of "subsistence farmers"2; everyone else will follow suite in due course.
1. Yes I know it's ironic, isn't it?
2. That's someone, errm, telological, perhaps. No-one called "the West" decided to remove this class of people. But "the West" provided the kind of society in which no-one wanted to be a subsistence farmer, and no-one had to be if they didn't want to be.
3. Picture: panel in font, Vallouise.
* rump administration loosens Obama's guidelines for self-driving cars: States are advised against setting up too many regulations; the Verge.
* How A Warm Winter Destroyed 85 Percent Of Georgia’s Peaches - 538.
* Economics says time to shut down some coal plants (even ignoring externalities) - Brian at Eli's.
OTOH, Irma may have done more to advance the sale of PV roofs & car-sized lithium batteries in the last week than
Green publicists have in the last decade. Absent air conditioning, a million or so Floridians won't be coming back till winter comes or 24-7 power is restored.
Until the advent of air conditioning, everything from Mar Del Lago to Motels wasshut and shuttered from the 15th of April til November.
"Certainly the proportion, and absolute number, of people living in absolute poverty has decreased over the last 50 or 100 years, and can be expected to continue to decrease, especially or almost entirely if their governance improves; "
As in the A1 family of scenarios in the SRES of course. Absolute poverty disappears by around 2070 or so. And climate change is a problem in the A1FI scenario, certainly, and isn't in A1T.
Certainly the proportion, and absolute number, of people living in absolute poverty has decreased over the last 50 or 100 years, and can be expected to continue to decrease, especially or almost entirely if their governance improves; see-also Harvey. That doesn’t help the ecosystems, of course. But the West has entirely removed the class of “subsistence farmers”2; everyone else will follow suite in due course.
That's a very optimistic view. I would agree with the first part, but...
Right now, subsistence farmers are still a very big part of the population in India, China, and most of African countries.
And the local governments having better things to do, from keeping a lid on local unrest to sending rockets into space, their peasants are basically let to fend by themselves.
It took us in Old Europe, what? From about the middle of 19th-century to the middle of the 20th-century to move from a mostly agrarian society to a heavily industrialized one, so about 50 to 100 years.
China has advanced a lot on the path of its conversion to industrialization, so they may "follow suite" - or even take the lead. OTOH, India just started about two decades ago, and still has a lot to overcome. Between a decade of droughts and the recent destructive monsoons, Indian subsistence farmers can't seem to be able to catch a break.
I'm afraid a number of societies won't have the time to complete their conversion from agrarian to industrialized before climate changes take care of their farmers the hard way.
"FWIW, I think that 3oC GW is certainly “dangerous”
Very true but blanket feel bad statements are like that, true but not needing to be useful.
Qualifications are what it is all about.
Who cares if it is 3 C hotter, on average in the Sahara Desert or Death Valley? Not a fair question as I am sure a lot oif people, who live in neither place, will suddenly feel all sorts of noble reasons to care and point them out.
The practicality is what happens to the rest of the world.
3C would certainly cause a changed world. Slightly different coastlines. Loss of some arable land but reclaiming of land in other areas. Vast parts of Northern Europe would become more productive and livable. Others would decline.
Better roofing would be in demand elsewhere.
Populations would have to shift and adapt. Gee is that so bad? Adaption?
Has no one had to move place ever in the past.
So yes 3C certainly could be very bad, catastrophic even.
It could be good, Garden of Eden even. Seeing it is unpreventable we had better get on with the Darwinism or prayer.
"Has no one had to move place ever in the past"
Oh, sure, plenty. Usually didn't go without a few bloody conflicts here and there, a bit of mass murder, and the collapse of the occasional culture.
Climate change is happening, humans are causing it, and I think this is perhaps the most serious environmental issue facing us.
[Thank you. You will find no-one here disagreeing with your first two points; the third is likely correct on the long term -W]
" subsistence farmers are still a very big part of the population in India, China, and most of African countries. And the local governments having better things to do.. their peasants are basically let to fend by themselves.
Borlaug having done his part on the productivity end, there remains the formidible problem of making water conservation cheaper than water , so sustinence farmers can afford to protect their crops from drought .
A couple of points.
On poverty, a large part of the global reduction in poverty comes from the Chinese industrialisation which, given its fueling by fossil carbon and vast consumption of other resources, is an unsustainable growth of wealth at the expense of future generations.
Seeing it is unpreventable...
It's largely unpreventable now, but it was 25-30 years ago when science started really stressing the message of the danger of warming the planet.
It could be good, Garden of Eden even.
Oh, it'll be "good" for some - pelagic coelenterates, pest species, tropical disease species, colonising generalists. The cynical might even say that the same goes for the non-human versions thereof...
For the average human in the street though, and more importantly, for those 'bottom' several billion humans in the dusty back-roads, there's little chance of a Utopia: it's simply physics, straightforward numbers, the laws of nature. No amount of appealing to the magic of wishful thinking is going to change the ecology of an overburdened, resource-contrained biosphere plunged into the tumble-drier of a profoundly altered environment.
It's ironic that the technoeconotopians think that air conditioners will save civilisation, but that the planet's own polar air conditioners are optional extras.
No-one called “the West” decided to remove this class of people. But “the West” provided the kind of society in which no-one wanted to be a subsistence farmer, and no-one had to be if they didn’t want to be.
You might want to review the history of "Enclosure" during the 16th to 19th centuries. Also this wee thing we in Scotland refer to as the "Highland Clearances"... In short, yes, people did quite deliberately and explicitly decide to remove that class of people, and the process was neither entirely welcomed by those affected, nor wholly free of violence.
[Sure; you can always find isolated example. But no, it wasn't policy that removed subsistence farming in general; it was a realisation that there were better ways to live. You don't imagine that the people currently doing it want to continue, do you? Happy peasants dying young for the sake of tourist photos and Western nostalgia? -W]
You don’t imagine that the people currently doing it want to continue, do you?
On the whole, no. However, my point is that subsistence farming in many areas was only partially eliminated in the nice, happy way of offering people better ways to live - in a large part, it was eliminated by forcing people off the land with violence (or the threat of it) and then leaving them to figure out how to cope themselves. For many of them, this involved the sort of cultural destruction and forced mass migration that might well be referred to as "genocide" these days, if it was based on ethnicity rather than class. A lot of them simply starved, and a lot more died in transit. Sure, many of the survivors did eventually end up with better lives, but many of them arguably did not - they ended up in the dark, Satanic mills of the early industrial revolution, or they ended up sharecropping (which is even worse than subsistence farming) in the New World.
Mostly, I'm just objecting to the historical ignorance (or possibly it's revisionism) that insists that the process happened organically. If it had, then nobody would have needed to pass a whole series of Enclosure Acts over the space of three centuries, just like nobody had to ban buggy whips, and certainly nobody would have needed to evict entire villages by setting fire to their roofs while everybody was in church.
Technooptimsta hope the decline in polar air condtioning will inspire Senor Bernard to buy an enormous aluminized sombrero and replace his grass lawn with silver sage or saltwort.
Bernard J "On poverty, a large part of the global reduction in poverty comes from the Chinese industrialisation which, given its fueling by fossil carbon and vast consumption of other resources, is an unsustainable growth of wealth at the expense of future generations. ... For the average human in the street though, and more importantly, for those ‘bottom’ several billion humans in the dusty back-roads, there’s little chance of a Utopia: it’s simply physics, straightforward numbers, the laws of nature."
Wrong. The greatest environmental futurist, by far, Julian Simon has explained that human ingenuity always outpaces resource scarcity. He has been proven to be correct over and over again. Human knowledge is growing in a manner similar to the compounding of interest helped greatly by the Internet and the increased ability to share knowledge. As a starter, I would recommend the article in Wired magazine entitled Doomslayer. See https://www.wired.com/1997/02/the-doomslayer-2/ You are simply repeating the Malthusian mistake which is over 200 years old and never dies.
Dangerous is driving down the highway above the speed limit.
Catastrophic is having an accident while driving down the highway above the speed limit.
Any amount of climate change in my opinion is dangerous in my opinion because of the risk of something unexpected going wrong with our ecosystems or ocean chemistry etc.