Roedd yn Uwchgynhadledd ryngwladol bwysig cyn Confensiwn Fframwaith y Cenhedloedd Unedig ar Newid Hinsawdd (UNFCCC) ym Mharis ym mis Rhagfyr 2015.  Daeth â thaleithiau a llywodraethau rhanbarthol at ei gilydd, ynghyd â chynrychiolwyr o ddinasoedd, llywodraeth leol a chymdeithas wâr ledled y byd.
The Summit was a key international conference on Climate Change in the lead-up to the crucial United Nations Framework Convention on Climate Change (UNFCCC) in Paris in December 2015.  It brought together states and regional governments along with representatives from cities, local governments and civil society from across the world.