Paris climate summit faces tougher job after modest Lima deal

Delegates rest during a break of the plenary session at the U.N. Climate Change Conference COP 20 in Lima December 13, 2014. REUTERS/Enrique Castro-Mendivil

LIMA (Reuters) - A Paris summit in 2015 will face a tougher task to agree a U.N. deal to slow climate change after the hopes of many that cooperation between Washington and Beijing would be a magic key to end global gridlock dissolved in chaotic preparatory talks in Lima.

At best, Paris may be a chance to reform a sprawling system of annual U.N. talks - more than 11,000 delegates attended the two-week talks in a tent city in Lima - and find ways to boost long-term action to stem rising greenhouse gas emissions.