Guardian: As environment minister in the spring of 2012, I was warned that the chance of avoiding a massive drought was about 3%. The two preceding winters were so dry that levels in reservoirs and the aquifers were dangerously low. Anything approaching normal summer rainfall that year meant a huge economic, social and environmental nightmare. We had been planning for the impact of the drought for 18 months before this conversation but as the summer drew near I started to wonder how we were going to keep the...