Environmental impact of food production of tomatoes would depend on the method of production and the season. Growing tomatoes in the winter in non-insulated greenhouses heated by coal energy would be very bad, obviously. Importing tomatoes by ship could be better in that case (CO2 tranport budget is usually under 10%), obviously seasonal produce is best.
Meat is not CO2 only, though. Other impacts of animal agriculture:
- Greenhouse gas emissions
- Deforestation (50% of pastures used to be forests)
- Land degradation
- Water pollution
- Water overconsumption
- Loss of biodiversity
- Antibiotic resistance
- Ocean dead zones
- Inefficient land and resource use
- Ethical concerns
- Contribution to zoonotic diseases
- Air pollution
- Eutrophication
- Soil erosion
- High energy consumption
- Chemical runoff from pesticides and fertilizers
- Destruction of habitats and ecosystems
- Inequality in global food distribution
- Public health risks from foodborne illnesses
- Nutrient pollution
- Strain on waste management systems
- Overfishing (40-70% of plankton gone, sharks 90% gone, fish almost gone in 2040's)