I think he's actually talking about he fact we've had the opposite problem. Cold weather and a great deal of rain. And there are news stories about poor crops here too.
Grass and trees grow well enough in this weather, but cereal crops need warmth and a dry spell to ripen. They don't do well in cold, waterlogged fields. The potato crop appears to have been affected by waterlogging too.
You'd think the abundance of grass would have been good for the livestock, and to an extent is has been, but we have been unbelievably busy here all summer dealing with livestock disease and illness when usually the summer is a very quiet period. The cold and rain seem to have promoted disease in animals at grass.
Countries plant the crops and devise an agricultural system suited to their usual climate. If the climate doesn't perform as expected, returns are going to be affected, whichever way the pendulum swings.
Rolfe.