India, Nov. 10 -- On the Nepal-Tibet border, the same river produced two destructive floods 14 months apart; August's killed over 1,450 people and left a $4.78 billion rebuilding bill. Last year, Hong Kong raised a typhoon warning 14 times; a normal year brings about six. Nepal is a landlocked least developed country; Hong Kong's per capita income is above $60,000. Vastly different economies, yet climate shocks are rising in both.

For anyone pricing risk for a living, the lesson is plain: The past is no longer a reliable guide. How can we better insure against rising climate shocks?

In September, the UN Environment Programme's report said the 1.5degC Paris limit will be crossed on a sustained basis within a decade on every central estim...