SYDNEY—Australia formally adopted a plan to realize net-zero carbon emissions by 2050 just days in advance of the commence of a United Nations climate summit, ending its position as an outlier among designed nations, a lot of of which had already established such a target.

But Prime Minister Scott Morrison disappointed environmental teams by not committing to a far more bold emissions-reduction intention for 2030. A lot of scientists say much better motion is desired to minimize emissions this decade if the world’s nations are to restrict the rise in world wide temperatures to 1.5 degrees Celsius, the intention in the Paris climate accord.