Climate change affects crops in different ways because there is more than one thing happening. Yes there is more CO2 and it will get warmer, but “warmer” means quite a few different things. I would like to offer a quick survey to help people appreciate what we are facing.
Let’s start with rising seas. A two meter rise in sea level may not seem like much if you are thinking of the cliffs of Dover, but for low lying places like Bangladesh and Florida it is huge. Some of the worlds best agricultural land is in river deltas like the Nile and the Mekong which are very close to sea level.
The greater threat from rising sea levels is not actual flooding, but infiltration of ground water by sea water. Once the ground water becomes saline the salt migrates up through the soil and turns productive land into a salt desert.
A two meter rise in sea level can affect agricultural land quite some distance from the ocean. A majority of the world’s food production is within 5 m of sea level.