ANALYSIS-Rising US population makes 2050 climate cut harder

* US greenhouse goals per capita tougher due to population

* Russia to have easiest cuts due to shrinking numbers

By Alister Doyle, Environment Correspondent

OSLO, Oct 12 (Reuters) - A rising population will make it harder for the United States to make 2050 cuts in greenhouse gas emissions than for Russia and some other rich nations with shrinking populations, a Reuters survey showed.

Leaders of the Group of Eight agreed in July to cut developed nations' emissions by 80 percent on average by 2050 in a costly shift to renewable energies. They said the target could aid a U.N. climate pact due to be agreed in December.

But the goal -- if implemented by each nation -- would allow Russian citizens to emit almost twice as much as Americans in 2050, according to Reuters comparisons of emissions and U.N. Population Division projections [ID:nLC274433].

"The biggest contrast is between the United States and the other industrialised countries. The demographic differences with Russia are stark," Brian O'Neill, a scientist at the U.S. National Center for Atmospheric Research, said of the data.

"Some countries could say: 'how come your emissions can be more than twice ours in a world where we're all meant to be doing our fair share?" said O'Neill, who also works at the International Institute for Applied Systems Analysis in Austria.