With changing climate it is difficult to predict who will win the 300 million year war. What has gone wrong when herbivores get the upper hand and strip plants bare? The battle ground is changing such that different conditions could favour either the plants or the herbivores. When the balance is broken we could have an ‘outbreak’, which is a situation where one side of the war gets an unfair advantage and grows unchecked. Will climate change compromise the abilities of plants, including our crops, to defend themselves?