> Livestock agriculture is the leading driver of climate change AND biodiversity loss.

I am pretty sure that's not correct, not even close [1]. Transportation is the main driver of gas emissions (28%) followed by electricity production (27%) and industry (22%). Agriculture (livestock and crop) is <10%.

In most countries, livestock can graze in areas where cultivations cannot happen (Australia is a good example iirc) and can help with soil health.

> Additionally, if we would let nature reclaim the land that's currently used for livestock agriculture, it has the potential to capture >100% of the CO2 emissions until 2050.

Most of the food livestock consume are leftovers of human-grade crops. So we would still "need to" have that cultivations going and throw the leftovers anyways. Or most likely some company would find a way to feed humans that.

https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emis...

According to this[0] Our World In Data article, which is based on 2018 data, livestock (including fisheries) produces about 15% of all emissions, assuming that animal-based products account for about a third of the supply chain costs of the food industry:

Total food emissions: 26%

Direct livestock + fish: 31% of that 26%

Due to livestock land use: 16% of that 26%

Due to crops for animal feed: 6% of that 26%

Due to supply chain (1/3 of total): (18/3)% of that 26%

Total: ((31+16+6+(18/3))/100)*0.26 = 15.34%

And according to this[1] Our World in Data article, transport makes up about 16.2% of emissions.

The analyses can differ depending on how far you "travel up the chain" of production, but it appears that transportation and animal agriculture are within the same ball-park, plus or minus 5% perhaps.

> Most of the food livestock consume are leftovers of human-grade crops.

This is incorrect. Most livestock feed is soy, and humans can and do eat soybean meal. About 98% of soybean meal is used for animal feed and only 1% is used to produce food for people.[2] For soybeans as a whole, only about 6% grown worldwide are turned directly into food products for human consumption.[3]

[0] https://ourworldindata.org/emissions-by-sector

[1] https://ourworldindata.org/emissions-by-sector

[2] https://www.canr.msu.edu/news/where_do_all_these_soybeans_go

[3] https://www.ucsusa.org/resources/soybeans

No, even if most of livestock feed was soy (I am pretty sure it was corn, but whatever), most of the food they are feed as dry matter is not edible by humans: https://www.sciencedirect.com/science/article/abs/pii/S22119...

I would like to see where that 98% really comes from, the links you posted talk about 70% (and most of that being consumed by poultry, not cattle). And even that seems excessive [1]. I would love to see a clear separation between the soybean. meal (leftover from oil and soybean grinding) and explicit feed grade soybeans.

[1] https://www.usda.gov/sites/default/files/documents/coexisten...

Globally, GHG emissions from livestock agriculture make up between 1/4 and 1/3 of all GHG emissions (depending on the source, but here's a good one: https://ourworldindata.org/environmental-impacts-of-food). And this does not take into account CO2 sequestered by land that is already converted to cultivated land (i.e. not natural vegetetation) - so the potential of additionally sequestering carbon is much higher.

That's right that Australia doesn't have a lot of natural forests, but even there natural vegetation is better at sequestering carbon than land that has been converted to be used for agriculture. But if you look at this map here [0], you'll see that Western Europe, South America, Southern Africa and South East Asia all have great potential to capture CO2 if we let the natural vegetation regrow.

> Most of the food livestock consume are leftovers of human-grade crops.

No it's not. Furthermore, from a protein and nutrition stand-point, the plants we grow today are enough to feed the whole world.

0: https://www.nature.com/articles/s41893-020-00603-4.epdf?shar...

> This seaweed won't even start solving this problem.

To the extent that the problem extends much further than level of consumption of cattle, that is true. But if widespread adoption of feed can effectively reduce methane emissions from cattle, as you said it targets one of the primary drivers - that's more than a start. This helps you visualize the impacts of various solutions, notice what happens when all other things held equal you drop methane - https://en-roads.climateinteractive.org/scenario.html?p1=45&...

> if we would let nature reclaim the land that's currently used for livestock agriculture, it has the potential to capture >100% of the CO2 emissions until 2050.

This is a moot point considering that trees and plant numbers could be increased in many other areas, particularly where they are felled in high numbers, and not all pasture land is appropriate for plant agriculture or otherwise.

There is a short-term battle and a long-term one. We do need to curb emissions in the short-term substantially, which will require innovation and policy changes. Long-term, the fact is land encroachment and destruction scales with the population; we all have an environmental footprint, and slightly increasing its efficiency will never outpace and counteract the impact of perpetual population increase. It's projected to curb more in the future as more of the global population gets lifted out of poverty, and access to contraceptives is more universal - however, this could be accelerated. There's no reason we can't quash global poverty further right now.

Almost 80% of the usable land is used for livestock agriculture. In which other areas do you propose to increase trees and plants?

This seaweed additive they propose is a distraction. Even if it would work, it's a band-aid at best. The real, more simple, cheaper and healthier solution is to make meat and dairy from plants directly.

> of the usable land

What are you referring to when you say "usable land"? What means usable? Presumably you refer to agriculture and I'm not sure where your number comes from. 42 percent of the land acreage of Canada is covered by forests. This is the percentage forest cover by each State in the U.S. - https://en.wikipedia.org/wiki/Forest_cover_by_state_and_terr...

> In which other areas do you propose to increase trees and plants?

Anywhere else appropriate.

> This seaweed additive they propose is a distraction

It's a solution, given that among the problems framed is the level of methane emissions.

> Even if it would work, it's a band-aid at best.

There has been research papers illustrating the impact of seaweed in cattle feed for years now - it works.

No one is framing this as the entire solution to global warming. If it can curb methane to that extent, it has a substantial impact.

> The real, more simple, cheaper and healthier solution is to make meat and dairy from plants directly.

We already have "alternative" products on the market which aren't that popular, but no actual lab-grown meat on the market. The "real" solution (to this minor subset of a larger issue) is one that exists, or could viably be cost-effective enough to consumers tastes. I see no suggestion that lab-grown meat would be cheap, or healthier, or simpler.

By usable I mean usable for agriculture: https://ourworldindata.org/environmental-impacts-of-food

I'm not talking about lab-grown meat, I'm talking about plant-based meat and dairy. The most important thing to do is to creat plant-based meat and dairy alternatives that are better than animal-based products. It's hard but it's possible already possible today (e.g. see Impossible Foods).

Well, you can't just "let nature reclaim land", people own that and you can't force them to turn it into a nature preserve. There's a huge violation of private property rights implicit in your proposition.