Can Top Polluting Nations Ever Cut Their Emissions?: QuickTake

Efforts to cut greenhouse-gas emissions are falling short of what scientists say must be done to avoid catastrophic climate change. At a climate summit convened on the margins of the United Nations General Assembly in New York this week, countries were encouraged to raise their climate ambition and targets.

So far, 47 of the 195 Paris Agreement signatories have submitted their latest plans for hitting emissions targets under the 2015 pact and another 52 parties have made summit announcements.

The outlook appears bleak. While China, the world’s largest polluter, on Sept. 24 set a goal to slash greenhouse gases from ...