JOHANNESBURG – As delegates gather in South Africa to plot the next big push against climate change, Western governments are saying it’s time to move beyond traditional distinctions between industrial and developing countries and get China and other growing economies to accept legally binding curbs on greenhouse gases.

It will be a central theme for the 20,000 national officials, lobbyists, scientists and advocates gathering under U.N. auspices in the coastal city of Durban starting Monday.

Their two weeks of negotiations will end with a meeting of government ministers from more than 100 countries.

The immediate focus is the Kyoto Protocol, the 1997 agreement requiring 37 industrialized countries to slash carbon emissions to 5 percent below 1990 levels by 2012.

Each country has a binding target and faces penalties for falling short. The U.S., then and now the world’s largest polluter per capita, refused to join Kyoto because it imposed no obligations on countries such as China, which has since surpassed the U.S. in overall emissions.

Now, with the Kyoto pact’s expiration date looming, poor countries want the signatories to accept further reductions in a second commitment period up to at least 2017.

“The Kyoto Protocol is a cornerstone of the climate change regime,” and a second commitment period “is the central priority for Durban,” says Jorge Arguello of Argentina, the chairman of the developing countries’ negotiating bloc known as G77 plus China.

But with growing consensus, wealthy countries are saying they cannot give further pledges unless all others – or at least the major developing countries – accept commitments themselves that are equally binding.

The European Union is bringing a proposal to Durban calling for a timetable for everyone to make commitments by 2015.

Separately, Norway and Australia set out a six-page proposal for all governments to adopt a phased process of scaling down emissions.

Japan, Canada and Russia, three key countries in the Kyoto deal, announced last year they will not sign up to a second commitment period.

It’s an old debate that has been intensifying with the rapid growth of economies such as those of China, India and some in Latin America and the wealth as well as high carbon emissions they generate.

The division of the globe into two unequal parts was embedded in the first climate convention adopted in 1992.

The industrial countries – the U.S. chief among them – have long questioned whether definitions of rich and poor, drawn up 20 years ago, should still apply.

That was one reason why the U.S. backed out of the Kyoto Protocol.