An independent Alberta would be recognized internationally and join the UN as a matter of course.
Stated by: Implied by some Alberta independence proposals
Summary
International recognition is a political act, not an automatic result of declaring independence. A new Alberta state would need other countries, including Canada, to recognize it, and UN membership requires a Security Council recommendation and a General Assembly vote. Analysts note nothing about admission to the UN or bodies like the IMF and WTO would be guaranteed, and a contested or hostile split could leave Alberta's status in limbo. Treating recognition as a formality overstates how it works.
Evidence
Constitutional analysis stresses that nothing would be guaranteed for a new Alberta state, including admission to the United Nations, currency, defence, or trade arrangements.
The Conversation (what if Alberta voted to separate) (opens in a new tab)
A statehood review notes recognition is not guaranteed, especially from Canada or its allies, and delays or refusals could keep Alberta out of the UN, IMF, and WTO.
State Succession Index (Alberta referendum analysis) (opens in a new tab)