I come from a farming family, we do produce lots of crops including wheat.
If temperatures go warmer by a degree. It won't matter. Really it won't.
however, as temperatures change, rainfall patterns change.
For example, we get rain from westerlies in Northwest India from Dec-End feb.
So wheat gets water at times of growth, and while harvesting end march - late april there is hardly any rain.
Over the past 10 years it has changed. It can rain heavily in march-april also, which will destroy almost ripe wheat crop.
Heck, westerlies are active into may now.
Such change in rainfall patterns can destroy crops.
Another example, the himalayas got a lot of snow this year. Much more than normal. Good thing. But all of it started in feb in some regions, which will result in poor apple crop this time in some regions.
Any climate change which alters patterns(not necessarily warming or cooling, but change) has the potential to destroy agricultural yields. So climate change is a bad thing in general for agriculture unless it happens over millenia.
I would not mind climate change if it happened gradually like in olden times. We would adapt. But rapid change in rainfall patters over 3 decades. Everything goes for a toss.