The Short Version
The claim correctly identifies the core structural shift from Kyoto's top-down binding emission caps to Paris's bottom-up system of nationally determined contributions (NDCs), where countries set their own targets. However, calling the framework "voluntary" oversimplifies its hybrid legal nature — the Paris Agreement is a legally binding treaty with mandatory procedural obligations, even though the numerical emission targets themselves are not binding. The term "gradual emissions reductions" reasonably describes the five-year ratcheting cycle but overstates the guarantee of progressive outcomes.