I'm not convinced the wood used in the Portland airport project is net negative in itself, once you factor in the emissions of harvesting, processing and transporting it. I.o.w. leaving the ugly old roof in place would probably have been better, in terms of CO2eq emitted.
That's 3.364×10^6 m3, 1 m3 of concrete weighs 2.4 tonnes (I'm sure it varies), so roughly 8 million tonnes of concrete.
https://www.concreteconstruction.net/_view-object?id=0000015...
I'm not convinced the wood used in the Portland airport project is net negative in itself, once you factor in the emissions of harvesting, processing and transporting it. I.o.w. leaving the ugly old roof in place would probably have been better, in terms of CO2eq emitted.