> The problem isn't the cold, it is growing season length, and sunlight, and shade. > So it is not only cold which restricts crop growth, but the length of sun

> The problem isn't the cold, it is growing season length, and sunlight, and shade. > So it is not only cold which restricts crop growth, but the length of sun per day. > Anyhow, point is, warmer Earth doesn't mean cropland opens up. Oh, surely it will help to at least some extent? Wheat, and even more so barley and rye, have been grown up to at least the middle of Finland and northern(ish) Sweden for hundreds of years. And those were the old not-so-refined varieties.