The world has rightly come a long way since climate concerns were a fringe issue, Chancellor Sajid Javid writes.
"A colossal waste of money", according to critics.
Hammond is the second cabinet minister to reveal they will quit if Johnson wins the Tory leadership.
Philip Hammond says shutting down parliament to stop MPs from blocking no deal "would provoke a constitutional crisis".
May's successor may "have to explore other democratic mechanisms" in the face of no-deal, Chancellor says.
The German chancellor supports May's deal – but critics say it's her very own refugee policy that created the Brexit problem.
It comes as figures highlight the importance of biodiversity to the UK economy.
Analysis suggests planned increases will be swallowed up by NHS, defence and international aid pledges.
Downing Street Says No-Deal Brexit Won't Cancel Budget Spending Plan - Hours After Philip Hammond Said It Would
"Tory budgets are usually plunged into chaos after the Chancellor sits down, not before he even stands up."
But will it be enough?