For instance, it's multiple times less co2 impact for me eating an avocado here in Norway that's been shipped half the globe around from south america, compared to eating meat from the local farm. The scales are just so incredibly different in production (vs transportation) that it's not to "gotcha" many believe to claim that something imported is automatically bad.
Next to that it's not always Plants vs meats. In many places only cattle can graze but not much of value can grow.
The CO2 issue is really a terrible comparison. Everything cows put out has been put in from the air. The airplanes are excreting new/old CO2 taken from fossil fuels. Some claim cows are still worse because of methane, but they forget to mention methane only had 12 years lifespan in the atmosphere.
The produce to feed the cattle is often detrimental to the environment too. They're not cutting down rain forests in Brazil to produce soy for meat substitutes but rather for produce to feed animals.
But it's absolutely important to eat local and if you're gonna eat meat ensure that the animal was fed local produce too.
The vast majority of soy production, particularly the environmentally destructive production that’s converting rainforests in South America into farmland, is for animal feed, not human consumption: https://ourworldindata.org/soy