"There has been a shift to understand that climate change is not only an environmental challenge, it’s an economic, a social challenge and does require active engagement of almost every member of the cabinet," outgoing U.N. climate chief Christiana Figueres of Costa Rica told reporters. Climate change has become a higher global priority and foreign ministers, usually among the most senior cabinet ministers, are well placed to coordinate action, said Figueres, previously a national negotiator and environmental expert.

Before Fabius chaired the Paris meeting, where almost 200 nations agreed a sweeping plan to end global dependence on fossil fuels to limit rising temperatures, environment ministers had been in charge of most of the U.N.'s annual climate talks since they started in the 1990s. "Climate change has become a core issue for diplomacy," said Elliot Diringer of the U.S. Center for Environment and Energy Solutions, saying the long-term success of the Paris Agreement would hinge on diplomatic skills to persuade ever tougher action to restrict emissions.

Reflecting this trend, Moroccan Foreign Minister Salaheddine Mezouar attended the start of the Bonn talks, which are preparing a high-level conference in November in Marrakech on implementing the Paris Agreement. Global warming "cannot be analyzed only from the silo of the environment ministry," said Tosi Mpanu-Mpanu of the Democratic Republic of Congo, who chairs a group of the 48 poorest nations at the Bonn meeting.

Mpanu-Mpanu said some environment ministers feel displaced from their area of expertise by foreign ministers. Some cope well with the new split but "in some countries it can create a lot of tensions," he said. Espinosa, who was also in the vanguard by hosting U.N. climate talks in Mexico in 2010 as foreign minister, said "we need both" environmental experts to solve technical issues and diplomats to understand the politics. In coming years, she will have to juggle issues ranging from developed nations' promises to provide $100 billion a year by 2020 to help developing nations cope with climate change, to some nations' worries that more extreme weather might trigger unrest or migration.

(Additional reporting by Susanna Twidale in Cologne; Editing by Tom Heneghan)

[This post originally appeared on Reuters.]