The world can save both financial and environmental costs by shifting toward a low-carbon economy over the next 15 years, a high-level panel says ahead of a UN summit.

The commission co-chaired by former Mexican president Felipe Calderon called for greater global action on renewable power, deforestation and clean technologies as part of the fight against climate change. The report said that the next 15 years would be critical, with the global economy undergoing major structural changes and time…