The greenhouse effect makes the upper atmosphere colder and affects the thin layer of ozone that shields us from harmful sun rays. This can lead to bigger ozone holes, especially over the North and South Poles. These holes let in more UV radiation, which could harm crops. A study on rice farming in Northern Japan shows that while warmer temperatures and extra CO2 help rice grow more, ozone damage from the holes might be so bad that it cancels out the benefits of warming and extra CO2. So, the idea that global warming is good for farming in colder places needs a closer look.