I wrote a blog post on applying Effective Altruism to climate change. I used information from Drawdown.org as well as my own analysis. The results show that many solutions that are often promoted like high-speed trains, electric vehicles, green roofs and others are actually very high-cost relative to their CO2 reduction. Less known solutions like silvopasture, restoring tropical forests, and managing food waste are actually much more cost effective per gigaton of CO2 abatement.
You can read the full blog here: https://medium.com/@tsloane/applying-effective-altruism-to-climate-change-e2d703f6414f
I'm curious to get your thoughts on approach and results.
FYI, some prior work (which partially agrees with you):
https://founderspledge.com/research/fp-climate-change
https://lets-fund.org/
Also, a bit of press (and research) on trees: https://www.theguardian.com/environment/2019/jul/04/planting-billions-trees-best-tackle-climate-crisis-scientists-canopy-emissions
It's encouraging to see agreements from multiple estimates on the effectiveness of forestry. On clean energy, note that spending a few dollars to lobby the government to in turn spend a lot of money might be a lot more effective (2nd link), perhaps that explains the disparity.
I think your calculation for the cost of promoting plant diets is conceptually mistaken. The amount of lost meat industry revenue is irrelevant. We want to know how much of our money will have to be spent. For that, it's relatively straightforward to look up the amount of advertising expenses required to reduce meat consumption (Animal Charity Evaluators has done this research).
This in turn makes me suspect that some of your cost estimates for other technologies might have a similar problem, measuring 'cost' in some other economic or business sense besides what we really care about. So these calculations are important things to include in the analysis.
Also, the 1800x spread between silvopasture and roofs should considered a significant overestimate due to the optimizer's curse.
That number seems pretty high. I wonder where most of the waste happens? Somewhat contrived scenario here, but suppose the drug store buys a new food product. Customers aren't having it so they throw it away. But then due to this awareness campaign, next time they keep it on the shelf--which means they don't have room for something customers do want to buy, so the customers drive to a different store, cancelling out the alleged food waste benefit. Again, contrived, I just feel like we should know why the waste is happening before working to stop it. There's a clear financial incentive not to waste food. Maybe it's mostly food with a short shelf life, like fresh vegetables, that people intend to eat but never do?
Instead of a public campaign against food waste, maybe a public campaign that shows the decarbonization benefit of everyday lifestyle changes. Which is better from an individual perspective: stop driving and take the bus to work, or cut food waste from 35% to 0%?
"Which is better from an individual perspective: stop driving and take the bus to work, or cut food waste from 35% to 0%?"
The drawdown project seems to suggest that cutting food waste is better, because it's rated third on its list whereas mass transit is 37th. However I hesitate to suggest people follow the guidance of Drawdown. I contacted them a few years ago (before the big media splash) with some questions about their methodology and got no reply. So I don't feel willing to endorse (or condemn) their work.
Surely some food emits much more carbon than other food. Maybe we could just tax food based on how much carbon it emits? Then people won't want to throw it away because they don't want to waste their money. (And they'll also substitute high-emission food for low-emission food.)
"I wonder where most of the waste happens?"
Most of the business-driven elements of the food supply chain are quite efficient, I'm told. I.e. each of manufacture, transport, and retail management. The waste comes almost entirely from customers buying things they don't need and then throwing them away.
If so, the most likely downside, if any, is the risk of people consuming food after its use-by date.
My source for this claim is a pitch from a food-waste charity. I consider this to be a slightly better source than a person chosen at random, however I didn't get the impression that the charity was rigorous about fact-checking its claims, so I can't promise this is correct.
That looks like an interesting attempt to answer a question many others have tried to answer . (These are also being discussed in an AAAS forum where people try to figure out what, can, and should be done---i have seen quite a few analyses and reccomendations of varying technical sophistication, and while they overlap, its overwhelming and beyond my competency to do more than just see which looks best.
Your top 5 causes all look good to me, as well as your larger list in the 'green box' in your diagram.
I would probably have 10-15 causes all ranked about same level. Also, I might have causes 'geographically' clustered, ie people should work on ones nearby, however defined.
I tend to thijnk transportation may be underranked, as well as clean energy, though I may be wrong. I wonder if transportation includes all the road building, airports, and energy used to make cars, planes,ships, shipping containers etc. --'life cycle analyses. Aslo , transportation has indirect effects--sprawl, lifestyles, etc. Resorts, casinos, convention centers are buldings, but exist partly due to transportation. Alot more could be said.
if you google 'food loss and waste USFDA ' they have some numbers and reports that appear to go through the details---they say there is loss every step of the way. I remember my own stores used to throw away what seemed to be immense amount of fruit and vegetables, and things like yogurt and cheese, and bread and pastry. Now i can't tell because they have locked the dumpsters to keep people from getting free food, there is some organized collection of unused food, and also they do the trash now at times I am not around.
I tend to think alot small things like diet, food loss, and transportation actually could add up and also be 'easily implemented' in the short term, while the more difficult ones requiring engineering/technolopgy would be done as they became feasible.
But as anyone familiar with things like addiction , cigaerette use, obesity, diet change to even a low meat diet (i forget the term), views on issues like religion, evolution, sex, politics, economics , etc even 'easy things to change' (behavior, or ideas) sometimes is no faster than making technological advances.