Brighton and Hove to be swept away?

We were rather bemused in the brighton.co.uk office to hear Gordon Brown's pronouncement that Brighton and Hove will be swept away in the not too distant future. Does he mean that global warming is Brighton and Hove's fault? How can this be?

• We all recycle don't we?
  
• We all shop at Infinity foods/have an allotment/get our vegetable boxes delivered from local farms and we certainly wouldn't be seen dead with a plastic bag.
• Our council is the largest authority supporting a voluntary ban on plastic bags.
• Our new Jubilee library is one of the most energy efficient public buildings in the country.
• The Forum for the Future's Sustainable Cities Index reported Brighton and Hove as the most sustainable city in the Britain.

What more can we do?