The United Arab Emirates is hosting international delegates for a world energy summit set for a Thursday conclusion.
Todd Stern, U.S. special envoy for climate change, told the delegates that world leaders need "real ambition" to address climate issues in a way that's consistent with their core interests.
"At the same time, we all must challenge ourselves to take a deeper look at what pursuing core interests really means," he said in his address. "The fact that moving to clean energy may have a cost in the short run cannot be taken as an excuse not to act."
Stern sparked controversy in 2011 when he told world leaders at a climate summit in Durbin, South Africa, that a 2-degree temperature limit used as a benchmark during climate negotiations was "a guidepost."
In later statements, however, he said "the United States is committed to finding a workable solution."
U.N. officials this week said private investments were needed to advance a low-carbon future. Stern, for his part, said countries can no longer view climate change issues as "an afterthought."
The World Meteorological Organization in a November report attributed warming trends to an increase in greenhouse gas emissions brought on by industrial activity.
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