Policy uncertainty and a lack of incentives leaves global renewable energy development far short of what's needed to abate warming, the IEA said from Mexico.

The International Energy Agency issued a report from the Clean Energy Ministerial meeting in Mexico, finding clean energy deployments are lagging behind what's needed to keep temperature increases in check.

IEA Executive Director Maria van der Hoeven said that, despite some positive signs in areas like electric vehicle and carbon capture and storage deployments, few renewable energy sectors were up to par.

"As a result, our ability to deliver a future in which temperatures rise modestly is at risk of being jeopardized, and the future that we are heading towards will be far more difficult unless we can take action now to radically change the global energy system," she said in a statement.

In an annual report published in early May, the IEA said annual government spending on new energy technology was around $17 billion. Tripling that level is required to shift the global energy focus from the status quo to low-carbon technologies, the report said.

The IEA's latest report found renewable energy accounted for 21 percent of the total electricity generated across the globe, while coal accounted for 40 percent.

U.S. Energy Secretary Ernest Moniz helped drive renewable energy momentum in the Western Hemisphere during his stop at the Mexican summit. The outcome of meetings there, he said, "will play an important role in facilitating the world's transition to a clean energy economy through regional and global cooperation."

A briefing from the U.S. Energy Department finds electricity consumption in the United States will increase at an average rate of 0.8 percent through 2040. The amount of demand met by renewable resources increases by 5 percent over the same time frame.

"National commitments on climate change require strong action now by energy stakeholders that will reduce emissions in the near term and that will enable more significant, longer-term reductions," the IEA's report said.