AmgineOccam's Razor. The data is wrong.
The odds of NB emissions peaking in 2011 is close to nil. But it does explain the 2011 data: that was the only year Canada's provinces reported emissions under the #KyotoProtocol; #Canada withdrew in 2012.
The #ParisAgreement did not come along until 2015. But research dating to 2019, not released publicly until 2024, showed #CA's measurements up to 600% lower than actual.
Only possible: economy collapse.