The Paris Agreement (PA) signed by 175 parties is now a Treaty since a quorum of signatories has been obtained. This Treaty is really the first important step taken to limit temperature increase, as pledges, if sustained and far more ambitious beyond 2030, would drastically limit the projected temperature increase from projections in the absence of measures to limit emissions of greenhouse gases. Contributions however fall short of the intentions to limit temperature increase to the +1.5° to +2° Celsius range since the onset of industrialization. Drawing on recent contributions, this paper reviews where we stand in tackling four challenges ahead: (i) taking fuller cognizance of the accumulating scientific evidence calling for urgent action; (ii) designing an architecture that will render effective the blend of ‘bottom-up’ and ‘top-down’ approaches; (iii) choosing policy options and tackling the slow transition to a low-carbon economy, and; (iv) raising finance and addressing burden sharing.
