"The IPCC report included the 'range' you quote as something of a concession to those who can only think/plan with dollars (never mind all those 'externalities' like human lives or our ecosystem that we are inextricably a part of)"
Human lives count as a cost to economists. External costs count as costs. Effects on humans of changes in the ecosystem count as costs. You are arguing from a mistaken idea of what economics is.
The IPCC presumably gave the range because if they badly misrepresented it the economists associated with the report would have resigned. They then qualified the real estimate to obscure how small the effect was estimated to be, relative to their rhetoric.
"It's "effects ON natural and human systems OF extreme weather...". Your response seems to have reversed these."
I don't think so. I quoted accurately. They are looking at effects of extreme weather, not just of extreme weather due to climate change.
If you think my response somehow is based on a misreading, perhaps you could explain why you think that.