Can anyone provide a sense of scale and impact if these results were to hold and if the majority of the world beef production were to switch to it?

My understanding is that around half of the world's greenhouse gas comes from livestock. Would it mean that this could cut our emissions by half? Would it be therefore much more cost efficient to have the government invest is growing and distributing red algae than whatever we're currently spending money on? Do we have a sense of how much it would cost to produce that much seaweed?

> My understanding is that around half of the world's greenhouse gas comes from livestock

That's not right. The highest number I've been able to find for the whole of agriculture is 24% of world greenhouse gas emissions.

https://www.epa.gov/ghgemissions/global-greenhouse-gas-emiss...

About 25% of that is methane from livestock (http://old.grida.no/graphicslib/detail/greenhouse-gas-emissi...)

So livestock is about 6% of total greenhouse gas emissions.

One also has to consider that the methane decays over a matter of decades. Other than CO2, which stays in the atmosphere until it is taken out.

So, even if methane takes a big share in current greenhouse emissions, its share in the accumulated greenhouse gases in the atmosphere will be lower.

The climate change it causes is temporary. (Disregarding runaway effects.)

https://en.wikipedia.org/wiki/Atmospheric_methane

Decades – we don't have decades to fix this.

Also, it decays into CO2, so to claim that its effects are temporary is misleading. On top of that, as long as the carbon is in a CH4 bond, it traps at least 20× as much radiation. Please don't dismiss the significance of methane emissions.

How many years do we have to fix this then? Alternatively, at what point will activists start saying we passed the point of no fix and give up their activism?

Here you go: https://croadsworldclimate.climateinteractive.org/

Honestly dude, rise above the cynicism (if that's how you meant to come across). You're a goddamn adult, and a well-educated engineer at that. Your current standard of living is at risk because of climate change (also millions of lives in poorer countries, but whatever). Spend 10 seconds on a Google search. "Activists" don't owe you any answers.

Never forget, despite what the sensationalists will tell you, climate change is very much fixable. Clean energy and better land management can and will get us there – and eventually, maybe in 200 years, we'll sequester enough carbon to get back to 350ppm. The question is about what happens in the meantime: if we act fast, we'll only get decades of food insecurity, war, and displacement, mostly in poorer countries [2]. If we delay further, we'll simply see much worse, and at home as well. But the "point of no return" rhetoric is nonsense and does nothing but paralyze people.

By the way, one of the easiest and fastest ways to catalyze at-scale solutions would be a revenue-neutral carbon tax at the source, effectively internalizing the social costs of climate change and letting the free market do its thing. (Look up "fee and dividend"; lots of folks are working on this already.)

[1] unless we hit some really unlucky runaway feedback loop, which is possible. [2] plus the disease epidemics and terrorism that come along with it – we don't live on an island.

You're the one writing phrases like "we don't have decades to fix this". How is one supposed to interpret that as anything but "point of no return" rhetoric, especially in light of that rhetoric actually being used with some frequency for the last few decades? I agree it's not helpful rhetoric, so maybe I should have aimed my comment at alarmists who use the rhetoric but who haven't fully embraced that it's too late, instead of the more general activists.

I'm fully on-board with planetary engineering projects. Those require engineering work and capital more than activism, though.

Do you want to make a prediction on the accuracy of whatever climate model you like (we can use the one you linked if you prefer) for what the temperature increase will be in 2 years, 7 years, and 12 years? We can record it at https://predictionbook.com/

Climate change is mostly no binary event. There is the risk of runaway effects, and possible extinction (though unlikely) but luckily we haven't hit those yet.

The political 2 degree goal is damage control. Climate models are complex and impacts harder to predict the more you divert from the current situation.

At 2 degrees the costs to society (social costs of carbon) far outweigh the mitigation costs. To hit the 2 degree target we have to act swiftly "we don't have decades to fix this" we are not (yet) at a "point of no return"

As green house gases are currently an externality, there will be no capital without activism.

I am too young to look back decades, but my understanding was that the "we don't have decades to fix this" guys in the 80s and 90s were more about running out of oil(and that turned out to be no problem as rising prices make more expensive extraction feasible) and that climate change as a concern only really started in the 90s (even though known long before that). And there are already damages that could have been prevented by acting swiftly in the 90s. We could have reached e.g. a 1.5 degree target. So the "we don't have decades to fix this" rethoric is fitting as ever.

I got to that point 3-4 years ago, personally. Even if it were economically and technically possible to get our act together, it has become entirely clear that the political system is incapable of acting quickly enough.

> Also, it decays into CO2…

If that carbon was already in the biosphere that’s mostly, fine long term. I worry a lot more about the carbon we keep adding to it, that wasn’t in the equation.

We should he focusing on plastics rather than methane.

The runaway effects are exactly the concern. Check out research on methane clathrates in the Mesozoic. Methane is 24x as potent a GHG than CO2.

When you see the gas flares in hydrocarbon production fields it may look like a waste (it is), but it has to be done because the alternative of releasing methane into the atmosphere is worse.

Methane contains carbon so it's not 100% temporary just mostly.

As far as I can see, those references do not mention whether they have corrected for the fact that methane is a ~20x more potent greenhouse gas than CO2. Are they counting per volume or per potency? That is an incredibly important distinction. Which, to be honest, they should have made, one way or the other.

They are in the units "greenhouse gas emissions" which corrects for the extra potency. The sad thing is that people often double-correct for such things.

Potency is typically assumed in the industry, the volume of methane is trivial compared to volume of CO2.

Random Gaurdian story puts methane : "Methane accounted for about 16% of global greenhouse gas emissions in 2015, according to the IPCC." (https://www.theguardian.com/environment/2017/sep/29/methane-...)

Wikipedia puts (with some question about the citation) methan at 4-9% of total greenhouse effect contribution, and CO2 at 9-26%. (And then water vapor way above that, at 36-72%.) https://en.wikipedia.org/wiki/Greenhouse_gas#Greenhouse_gase...

How are we producing water vapor more than say clouds?

I think the table is attributing greenhouse to gases generally, not to man-made gases; as a result, water vapor wins. (OTOH, turning clouds into drinking water at scale would be a cool way to fight global warming and deal with drought at the same time. My understanding is that storm seeding has a pretty seedy history, though.)

Your figure is from cowspiracy - it's worth looking up the film to discover its many other inaccuracies.

https://newint.org/blog/2016/02/10/cowspiracy-stampeding-in-...

Excellent article, thank you for linking it. I love and appreciate my vegan friends (have been one in the past, might be again in the future), but they need to be realistic about convincing others to change deeply-ingrained eating habits.

Short of an apocalyptic event, you could spend 100% of your spare time and energy trying to get people to stop eating meat and you'd be lucky to get a dozen lasting conversions. It's simply not an effective use of resources to make that your main/only focus.

Almost quit beef due to the info in Cowspiracy in which I believe they pointed out that if everyone were to switch to grass fed beef there would literally not be enough grassland to support it (this is probably true, with the assumption that various plant crops continue their unsustainable land footprint). However, having seen also "The Magic Pill" on Netflix, I've concluded the optimal solution is probably more, healthier beef, and less plant agriculture land. The real problem isn't the cows, it's what the cows eat, which is mostly corn, soy, grains etc. Put as simply as I can: if humans committed to eating fewer carbs, and eating grass fed fatty meat and high quality plant oils for the bulk of their calories, the resulting system would produce huge carbon capture because grassland in its 'growth phase' is a very efficient carbon sink, and is more supportive of healthy soil than fields of corn, soy, and grains.

So you chose to keep eating beef, because you think it's possible to create sustainable beef, even though the beef you do eat is not sustainably sourced?

How is it possible to product carbon capture, if all the grass is being consumed by cattle who then either exhale it or get eaten by humans who exhale it?

I understand the skepticism. I actually try to eat grassfed beef where budgetary constraints allow. In my opinion, grassfed beef today is the most sustainable land -based option given that the person consuming it is fat adapted. If eaten it in the traditional American diet of steak, potatoes, often beer, and bread, the result of this is a less efficient metabolism, the net result of which is more unsustainable agriculture because the person is going back to relying in part on intensive plant agriculture. I have an answer to the exhalation question, which I think is important to understand. The hydrocarbons generated by photosynthesis in the grass go into the cow, become protein and fat in the cow, and then go into the human, and become a hydrocarbon based store of energy. Most of the result of the use of this store is energy, heat, and two biproducts (H2O and CO2) (the efficiency ratios here matter and they are favorable in both healthy cows and humans). As long as we have a human/animal population on earth, we will have a system that produces energy (muscle movement and neurons firing), heat (waste from the inefficiency of our neuro-muscular-skeletal system) and CO2 and H20. The question, which I think grassfed beef addresses, is what is the most efficient way to take sunlight, water, and CO2, and convert that into energy for the human/animal population to use? To this I'd add in my optimal system we actually address the dual-threat type problems of overfishing and ocean acidification, and encourage sustainable harvesting of smaller fish with population management controls (ie sardines and anchovies).

The economics of veggie proselytism actually look pretty good.

Animal Charity Evaluators found that for every $11 spent in online ads, you could make one person go to a website, sign up with their email, and pledge to go vegetarian for a year. The average vegetarian [1] produces 1.5 metric tons less CO2eq per year, so this means that the online ads decrease carbon at a cost of $7.40 per ton. That's cheaper than buying typical carbon offset certificates ($10-$15 per ton).

Maybe it's too optimistic to assume that everyone who makes a pledge on the website actually stays vegetarian for a year, or that they were average-level meat consumers before. Still, animal farming is bad enough that reducing it is probably cost-competitive with other current CO2 reduction approaches.

[1] I'm not sure if their use of "vegetarian" means "completely vegan".

It is too optimistic to assume that anyone who makes a pledge on a website follows through on it for even one day.

It's the online equivalent to honking your horn for the protesters holding up signs next to the road. Easily done; easily forgotten.

I don't understand your math.

Wouldn't you need to look at the difference in CO2eq between an average non-vegetarian and vegetarian?

Sorry, typo – I meant to say less than. Fixed.

I think the real problem would be induced demand from cheaper prices of meat making up the difference.

The article says the correct amount is 15%, which is still extremely large.

Can anyone provide a sense of scale and impact if these results were to hold and if the majority of the world beef production were to switch to it?

Yes. According to the numbers of Food and Agriculture Organization of the United Nations, this would be about a 6.4% reduction in total green house gas emissions. See below for the numbers

> Total emissions from global livestock: 7.1 Gigatonnes of Co2-equiv per year, representing __14.5 percent of all anthropogenic GHG emissions__. This figure is in line FAO’s previous assessment, Livestock’s Long Shadow, published in 2006, although it is based on a much more detailed analysis and improved data sets. The two figures cannot be accurately compared, as reference periods and sources differ.

> About __44 percent of livestock emissions are in the form of methane__ (CH4). The remaining part is almost equally shared between Nitrous Dioxide (N2O, 29 percent) and Carbon Dioxide (CO2, 27 percent).

  http://www.fao.org/news/story/en/item/197623/icode/
  Food and Agriculture Organization of the United Nations

.44 * 14.5 = 6.38%

Did Molokai farming end because of soil depletion, or ...?

It ended because it isn’t cost effective.

Correct. We were told that it was no longer cost effective.

All that really means is that it became cheaper to ship food from other places. If the cost of shipping went up, Hawai'i agriculture would be "cost effective" again.

Doubtful. The cost of land here is crazy high and shipping costs affect us too. The double whammy is that it is expensive to get equipment and parts out to us. And don’t forget about labor costs.

The thread hypothesis is that there is a great deal of "idle" land. I've never been to Moloka'i and I don't know if that's true. When I lived on O'ahu it seemed that many people who basically lived on the beach would be glad to have agricultural work rather than e.g. catering to tourists. Shipping a tractor once is cheaper than shipping container-loads of vegetables every week, and that's more true the more that shipping costs rise. Tractors come from Asia now, anyway.