TOYAKO, Hokkaido — The drive for economic prosperity by the major nations still outweighs the urgent need to save an ailing planet.

A proposal by the Group of Eight industrialized nations to cut global carbon emissions by 50 percent by midcentury was rejected by the emerging economies Wednesday.

The G8 nations and eight developing countries, including China and India, failed to reach agreement on the 2050 goal or have it incorporated in the 16-country joint statement, issued Wednesday after a meeting in Toyako, Hokkaido.