As I commented last week, this is the Summary for Policymakers (SPM), the result of negotiations between governments. In other words it is a political statement, not a scientific document. The latter won’t be published until much later, probably long after COP26.
And as Guterres makes clear, the whole object of the SPM is to scare governments into signing up to the UN agenda at COP26.
Notably there is nothing in the BBC report, and therefore presumably in the SPM, to show that extreme weather has actually got any worse. Nor does it seem likely that the full scientific review either, given that the IPCC has failed to find any evidence in earlier reports. Indeed, the only mention is this:
Instead it is all about projections of doom and catastrophe, based on computer models written by grant addicted climate scientists. Every IPCC Assessment Report since the first in 1990 has threatened us with apocalypse, and none of their warnings of disaster have come true. But that has not stopped each report using ever stronger language.
Consequently we are treated to threats of a 2 meter sea level rise, an ice-free Arctic, an increasing occurrence of some extreme events “unprecedented in the historical record”, and wildfires.