[abarro81]

Fair enough, I guess I just assume that on insta we're likely to be in the world of colloquial usage!

[abarro81]

I don't agree that dividing the CO2e total by the lifespan simply doesn't matter

It doesn't matter to the maths (we can't agree to disagree on that, it's just maths!)

- why does that make the figure more relatable as opposed to more confusing?

Personally I agree it's less useful than just presenting total, but I can see why people would think using a per year metric would be more relatable, the logic being that people are more used to thinking about things in that form. Again to me it's arbitrary as it's easy enough to spot that the ratios are unaffected by this choice

CO2 emissions that happen in the future happen in the future - if you want to place the CO2e total in context then give the total and period over which the total is calculated.  Assuming the calculation is for an infinite converging series you could for example give the time period over which 90% of the emissions occur or give actual CO2e number for the lifespan of the individual (i.e. actual emissions) and divide by the 50 to give the impact over the persons lifespan, then give the post lifespan CO2e total.  If you want more context  then what are the average CO2 emissions per year for years 50-100, 100-200 etc?

But all of this would mean you were no longer able to compare total emissions without doing your own maths.

To me stating  "CO2e per year of life remaining for the person making the choice" is not simply an abstract choice it is a contextually disingenuous way of presenting the data.

I guess this is the bit where we can agree to disagree

The original statement:

'We recommend four widely applicable high-impact (i.e. low emissions) actions with the potential to contribute to systemic change and substantially reduce annual personal emissions: having one fewer child (an average for developed countries of 58.6 tonnes CO2-equivalent (tCO2e) emission reductions per year), living car-free (2.4 tCO2e saved per year), avoiding airplane travel (1.6 tCO2e saved per roundtrip transatlantic flight) and eating a plant-based diet (0.8 tCO2e saved per year)'

I agree the wording here is far from ideal - this is where I think the wording chosen is probably a little disingenuous.

Questions:

If I avoid car travel will I save on average 2.4 tCO2e next year - yes
If I avoid car travel for the next 50 years will I save on average 120 tCO2e - possibly depending on what happens to CO2 emissions from car travel over the next 50 years but it is relatively sensible estimate of the potential scale of the number.

If I don't have a child now will I save on average 58.6 tCO2e next year - no, nowhere near the actual number will be much smaller.
If I don't have a child now will I save over the next 50 years on average 2930 tCO2e - no, nowhere near  the actual number will be much smaller.

None of that has anything to do with total cumulative emissions; again best solved with some kind of discount rate to weight the importance of near-term emissions given the current context. That other link you posted sidesteps this by using net zero targets so that future emissions in the long term are downrated to zero, making this additional discount rate redundant (we don't need to discount 0). But we still get the same answer that having one fewer child is the best GHG choice you can make by a fair margin, even in a relatively short term!

[Nigel]

Lets assume that Desperate Dave eats his expected 16 cow patties a day, every day. And he does this forever from now on, since the unexpected (?) result of his experiment is that he becomes the world's strongest man, climbing 9c+ easily, fighting baddies, and using a blowtorch to shave.

The internet says that if you took all the available meat from a single cow then you're looking at getting 1600 burgers https://faunafacts.com/cows/how-many-burgers-in-one-cow/

So Dave is now scranning a whole cow every hundred days. Or 3.65 cows per year. No problem since he lives on top of Ben Nevis and just wrestles the nearest Highland coo down to Fort Bill Maccy D's to be sacrificed in the traditional paleolithic fashion that has been passed down through millenia since time immemorial; by a spooky clown in garish ill fitting dungarees.

Unfortunately the community of climbers who inexplicably follow him on socials are so enticed by the guarantee of uber-Ondra strength that they also switch to the diet. And as they grow in strength their families, friend's, and acquaintances adopt it too. Eventually all 8 billion humans on Earth are following the Desperate Dave diet. They all eat 16 patties a day. Yes, even the babies.

This results in a demand for 8 billion x 3.65 = 29.2 billion cattle to be slaughtered each year by archetypal red headed pasty skinned scotsman Mr R. McDonald. Currently humans kill about 300 million cattle per year for food, from a global herd of average size 1.5 billion. So if we assume that the current kill ratio of 1:5 is the sustainable one and remains the same, we now need a global herd of 146 billion cattle.

Not in my back yard! This madness must be stopped. I suspect a conspiracy between the Macleod and Mcdonald clans.

There is a serious point in there somewhere but I'm not sure what it is now.
 

[petejh]

Nigel that's completely unrealistic... Some people prefer KFC.

[petejh]

More seriously, Nigel did you watch the video with Myles Allen linked to by DaveMac? You should, if you're interested in quantifying who contributes what emissions.


Leading climate scientist Myles Allen says, "The traditional way of accounting for methane emissions from cows overstates the impact of a steady herd by a factor of four” – which, he says, is a problem. Allen goes on to say, "If we are going to set these very ambitious goals to stop global warming, then we need to have accounting tools that are fit for purpose… The errors distort cows' contributions – both good and bad – and, in doing so, give CO2 producers a free pass on their total GHG contribution."

Allen is a heavyweight in climate circles. The BBC described him as the physicist behind Net Zero. Based on his work with the IPCC in 2001, when quantifying the size of human influence on observed and projected changes in global temperatures. In 2005, he proposed global carbon budgets and in 2010, he received the Appleton Medal and Prize from the Institute of Physics for his work in climate sciences.

Over the past few years, he has been the coordinating lead author for the 2018 IPCC special report on “1.5 degrees” and he has long been a proponent of fossil fuel producers being made to take responsibility for cleaning up after the products they sell, rather than shifting that onus on powerless consumers. All of this leads to cows and why he cares that the math is right.

According to Allen, cows get lumped into the CO2 equivalent measurements, which the Oxford professor says is wrong. "And that," says Allen, "lets carbon producers off the hook because they can and do point to incorrect – yet widely accepted accounting of cows' contribution to GHG production. In essence, they're blaming the cows rather than taking full responsibility."

We invited Myles Allen to join us for a Conversation That Matters about why a steady herd size of cows is not the problem and a slow decrease in herd size, may in fact be part of the solution.

[IanP]

I don't agree that dividing the CO2e total by the lifespan simply doesn't matter

It doesn't matter to the maths (we can't agree to disagree on that, it's just maths!)

Haha.  I considered posting a response but since we just seem to be clogging the thread talking to each other I think it's better that I don't

But we still get the same answer that having one fewer child is the best GHG choice you can make by a fair margin, even in a relatively short term!

There is potentially an interesting discussion to be had (on a different thread or somewhere else!) about the actual real time impact on CO2 emissions of having children.  I agree its significant (though there are other questions about how avoiding children might impact developed countries with stable ageing populations) but as to how big that 'fair margin' is nobody seems to be suggesting any numbers.

[abarro81]

There is potentially an interesting discussion to be had (on a different thread or somewhere else!) about the actual real time impact on CO2 emissions of having children.  I agree its significant (though there are other questions about how avoiding children might impact developed countries with stable ageing populations) but as to how big that 'fair margin' is nobody seems to be suggesting any numbers.

The study that the article you linked appears to do well enough - it's an average per year from now until hitting net zero in 2060-2070, at ~4 tons/yr, or about 10x the average impact of going vegan over that period by their work.  To do really short term you'd need to build a bottom -up model instead of top-down (i.e. calculating individual journeys, which ones are "due" to a baby etc) but that would be torturous and a bit useless - it seems fair enough to assume that all emissions or the next 50yrs are key. Knowing that it's maybe 5x going vegan when the kid is 1, 20x at 18 and 1x at 40 doesn't really tell you much that useful!

[Nigel]

More seriously, Nigel did you watch the video with Myles Allen linked to by DaveMac? You should, if you're interested in quantifying who contributes what emissions.

No I didn't. In fact I haven't actually read DMac's posts about this or (anything else) as I don't really use social media! Frankly I know relatively little about the details / science of climate change, which is not something I'm proud of so perhaps I will give this a watch sometime. Cheers for the heads up.

[SA Chris]

Info overload on his IG right now. Almost becoming a torrent.

[tommytwotone]

I didn't realise I was signing up to The Lancet when I followed him on The Gram.

[MischaHY]

Info overload on his IG right now. Almost becoming a torrent.

34 posts in the last two weeks and of those 28 of them are on this topic. 

[Wellsy]

Evidently a burger patties only diet hugely increases instagram output, *scratches notes*

[cheque]

I’ve unfollowed him. He’s lost it.

[GazM]

So after all those posts his summary is: most people should eat a balanced diet of locally and ethically produced animal and plant foods.

Who knew?

No idea how a month of Macdonald's patties has anything to do with that.

[andy moles]

I dipped in long enough to read him arguing with the 'other' extreme, some loony conspiracist carnivore.

Whatever hill this is, he seems to be committed to dying on it!

[Danny]

Really quite an astonishing amount of effort to not be wrong on the internet.

It would have been better for him to simply note that his heavily meat-based diet is important for performance, health, and wellbeing, but to also admit that this is less than ideal for the environment.

[petejh]

Better for who?

[GazM]

Better for who?

The people reading that are trying to work out what his very long-winded point is.

I got as much from his last 25 words as his last 25 posts.

[abarro81]

I think his point, long ago, was pretty much "I'm doing this funny experiment on myself, I wonder what will happen" [actual quote: "it's just a personal experiment. It’s not science. I just want to see if eating Mcdonald’s beef has any divergent effects from my previous animal based diet experiments of mostly steak"]. Then hundreds of people jabbed him endlessly about eating meat so he dumped all his thoughts on the topic into various posts. Insta obviously isn't exactly an ideal format for anything long, and the comments are useless for anything more then sycophantic bollocks or calling somewhat a knob, so it all became a bit jumbled.
Unlike others on here, I don't really see this as a hill he's dying on, that he's lost it, etc. He just should have written a blog post instead!

[Bradders]

Really quite an astonishing amount of effort to not be wrong on the internet.

Implying that....he's right?

I think his point, long ago, was pretty much "I'm doing this funny experiment on myself, I wonder what will happen" [actual quote: "it's just a personal experiment. It’s not science. I just want to see if eating Mcdonald’s beef has any divergent effects from my previous animal based diet experiments of mostly steak"]. Then hundreds of people jabbed him endlessly about eating meat so he dumped all his thoughts on the topic into various posts. Insta obviously isn't exactly an ideal format for anything long, and the comments are useless for anything more then sycophantic bollocks or calling somewhat a knob, so it all became a bit jumbled.
Unlike others on here, I don't really see this as a hill he's dying on, that he's lost it, etc. He just should have written a blog post instead!

Seconded. At the very least he's clearly done A LOT more research than, I suspect, 99.9% of people have and has formed a view from that. As opposed to half arsing it by reading a few Guardian articles and then virtue signalling on social media.

[remus]

I think his point, long ago, was pretty much "I'm doing this funny experiment on myself, I wonder what will happen" [actual quote: "it's just a personal experiment. It’s not science. I just want to see if eating Mcdonald’s beef has any divergent effects from my previous animal based diet experiments of mostly steak"]. Then hundreds of people jabbed him endlessly about eating meat so he dumped all his thoughts on the topic into various posts. Insta obviously isn't exactly an ideal format for anything long, and the comments are useless for anything more then sycophantic bollocks or calling somewhat a knob, so it all became a bit jumbled.
Unlike others on here, I don't really see this as a hill he's dying on, that he's lost it, etc. He just should have written a blog post instead!

Word. Other viable options include making a 4hr youtube vid that everyone can ignore without getting their knickers in a twist.

[andy moles]

When I say dying on a hill, I'm assuming that that amount of time posting and handling combative replies on social media can't be good for someone. Maybe I'm wrong, and he's having a ball!

[SA Chris]

Really quite an astonishing amount of effort to not be wrong on the internet.

Implying that....he's right?

I think he's referring to this

https://xkcd.com/386/

[Danny]

Really quite an astonishing amount of effort to not be wrong on the internet.

Implying that....he's right?

I think his point, long ago, was pretty much "I'm doing this funny experiment on myself, I wonder what will happen" [actual quote: "it's just a personal experiment. It’s not science. I just want to see if eating Mcdonald’s beef has any divergent effects from my previous animal based diet experiments of mostly steak"]. Then hundreds of people jabbed him endlessly about eating meat so he dumped all his thoughts on the topic into various posts. Insta obviously isn't exactly an ideal format for anything long, and the comments are useless for anything more then sycophantic bollocks or calling somewhat a knob, so it all became a bit jumbled.
Unlike others on here, I don't really see this as a hill he's dying on, that he's lost it, etc. He just should have written a blog post instead!

Seconded. At the very least he's clearly done A LOT more research than, I suspect, 99.9% of people have and has formed a view from that. As opposed to half arsing it by reading a few Guardian articles and then virtue signalling on social media.

In much the same way that 9/11 truthers have done more "research" than 99.9% of people on the properties of metal. Motivated reasoning + scientific training + Google Scholar =/= a well formed opinion.

I'd give him the time of day on anything nutrition. But he's not a climatologist, or an ecologist, or an earth system scientist. Anyone in any of those fields has done 1000% more research than he has on the topic.

Not that he isn't entitled to his take, of course, but it's so clearly reactionary and lacking in *any* epistemic humility that I can't help but be disappointed.

[abarro81]

Motivated reasoning + scientific training + Google Scholar =/= a well formed opinion.

The downside being that that probably describes most scientists, at least up to post doc level!

I'd give him the time of day on anything nutrition. But he's not a climatologist, or an ecologist, or an earth system scientist.

He's also not a nutritionist, AFAIK, he's just done what you rubbished above...