[WithinReason]

I everyone in the world adopted a vegan diet CO2 emissions would drop by 13%. Still eating pork, poultry, eggs and fish would reduce it by 8.6%:

https://ourworldindata.org/carbon-opportunity-costs-food

[mrob]

That's "CO2e" (CO2 equivalent, measured in global warming potential), not CO2. The time scale isn't specified, despite making a big difference in some cases, so I'll assume it's calculated over 20 years, which seems to be the most common. It's important to distinguish CO2 from CO2e, because a large part of CO2e emissions from animal farming are methane, which is a more potent greenhouse gas than CO2. Methane emissions could be reduced in multiple ways, e.g. we could switch to farming kangaroos, which don't produce methane, or supplement cow feed with seaweed, which was found to dramatically reduce methane production:

https://journals.plos.org/plosone/article?id=10.1371/journal...

[aziaziazi]

We also may stop it altogether, kangaroo included and gain:

- those 4.4% co2e difference, which is quite consequent

- freshwater savings

- land savings (especially forest)

- the ability to feel morally good when looking and thinking about the food we eat

[uxcolumbo]

It's not just about CO2 - it's also that the large scale meat & dairy industry requires way more resources, destroys natural habitats and creates a ton of pollution.

[myshpa]

From the article you've linked:

"In a hypothetical scenario in which everyone in the world went vegan by 2050, the regrowth of trees and wilderness could sequester around 547 billion tonnes of additional CO2. Each year we emit around 36 billion tonnes of CO2 from fossil fuels, so that’s equal to around 15 years of emissions at our current levels. They also estimate an additional 225 billion tonnes of CO2 could be stored in soils ..."

That's much more impactful than reducing emissions alone. It would store a load of carbon while preserving biodiversity (paramount for healthy ecosystems).