North America and the UK don't grow avocados, so they're imported. The farther a food is from its source, the bigger the impact.
Tom Cumberlege, associate director of Carbon Trust, says packaging, processing, transporting, and cooling avocados have other impacts.
They need twice as much water as oranges and are often grown in water-scarce regions.
Avocados use a lot of water, worsening Mexico and California's droughts and heatwaves, making it harder to grow the fruit, leading to more deforestation to farm it, etc.
Contrary to popular belief, avocados, or "green gold," are driving Mexico's economy, especially in Michoacán state.
One avocado cartel reportedly made US$152 million by extorting local farmers with "taxes" and threatening death if they didn't comply.