When Warren Buffett held his annual shareholders meeting last weekend in Nebraska, investors obsessively discussed everything that the Sage of Omaha said about the equity market and his succession plans.

But another intriguing issue, buried deep in corporate filings, went largely ignored: Berkshire Hathaway has quietly “constrained the volume of business” it does in the reinsurance world because of “management’s assessment of the adequacy of premium rates”. In plain English, this means Mr Buffett is more reluctant to insure people against natural disasters – because it no longer pays.

Investors and central bankers alike should take note. A casual observer might assume Mr Buffett’s move has arisen because natural disasters are becoming more unpredictable. After all, just this week the White House released a report showing that climate change is accelerating, creating weather extremes.