Twenty local governments, representing areas producing 5 percent of global climate-changing emissions, have committed to targets to cut those emissions, with the majority also setting goals for renewable energy, a platform uniting them said on Thursday. The Compact of States and Regions, launched last September, said more local governments would join the effort over the summer, making their combined emissions savings one of the most significant pledges to be presented ahead of a new U.N. climate deal due in December.

The state and regional governments that have already set targets include British Columbia, California, Ontario, Oregon, Quebec, New York, Washington, Rio de Janeiro, Sao Paulo, the Basque Country, Catalonia, Lombardy, Rhone-Alpes, Scotland, Wales, Australian Capital Territory and South Australia.

Christiana Figueres, the United Nations' top climate change official, told a gathering in France of local leaders from around the world that the actions of cities and regional governments to curb global warming offered huge benefits in public transport, cleaner air and better waste management."You are doing nothing less than creating a new reality for the world," she said. "You are making possible that we are moving toward a low-carbon, high-growth society — both of those together.

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The targets set by the 20 sub-national governments, representing more than 220 million people and gross domestic product of $8.3 trillion, vary in their ambition. Several have set the bar high, pledging to cut greenhouse gas emissions by 80 percent by 2050. The German state of Baden-Württemberg is aiming for 90 percent reductions by 2050, while Australian Capital Territory wants to cut 100 percent by 2060.

On Wednesday, French President Francois Hollande encouraged all local governments to get involved in the fight against climate change and to work for a successful outcome at the Paris climate talks. "No matter how strong national contributions are, in reality this engagement will be empty, if it is not fulfilled by local governments," he told the conference in the French city of Lyon.