NEW DELHI (Reuters) - A meeting of a 17-country group of the world’s worst polluters in Italy this week will likely agree on a token joint declaration because President Obama will be chairing, Indian officials said on Sunday. The 17-member Major Economies Forum (MEF) is trying to agree on a climate plan on the sidelines of a G8 summit in Italy. A substantive pact would go a long way in defining a new U.N. climate treaty due to be agreed in Copenhagen in December.

The MEF members, who discussed a draft text in Mexico last month, account for 80 percent of global emissions.

Officials said persistent differences, particularly over the size of reductions in carbon emissions and the base year for comparisons, might scupper efforts to agree a joint declaration and result instead in a chairman’s summary of countries’ views [nL3655179].

However, a top Indian climate official said: “A chair’s summary would have been seen as a failure, and given that President Obama is chairing the MEF meeting there is going to be a political declaration.”

“Whether it is going to be a meaningless or meaningful document is left to the reader’s judgment.”

Leaders of MEF nations are due to meet on Thursday, July 9 on the sidelines of the G8 summit. But climate officials are holding urgent negotiations on Tuesday to agree on the MEF declaration.

The current draft statement, discussed at talks in Mexico last month, omits a base year for emission comparisons and there is disagreement over language and nuances on long-term goals, Indian diplomats said.

Developing countries, including India, would like a base year of 1990 because this would force rich nations to cut back their emissions more sharply, leaving developing nations more carbon space to expand their economies. But wealthy nations, such as Japan, are pushing for a more recent base year.

The final MEF communique, however, is unlikely to mention any key figure to avoid upsetting countries such as India, which says mentioning any figure or target now would be prejudging the outcome of negotiations for a new U.N. pact in Copenhagen.

“India feels that the declaration will aim to demonstrate the political intent of the major economies to arrive at a consensus for having a robust agreed outcome at Copenhagen,” Dinesh Patnaik, a top Indian climate official, told Reuters before leaving for Italy for Tuesday’s negotiations.

Developing countries want their industrial counterparts to reduce emissions by up to 40 percent below 1990 levels by 2020, while rich nations want developing states to commit to boosting their economies in an environmentally friendly way.

The MEF proposal says major economies are to consider setting a goal of halving greenhouse gas emissions by 2050, a target developing nations say leaves them less room to grow.

“Prospects of any substantial agreement is poor,” said former India foreign secretary Kanwal Sibal. “The debate will continue.”