Cities must make dramatic emissions reductions to close the gap between commitments and reality, according to a new UN report. | Getty Images

Climate Mayors make big promises at international summits?but some are expanding fossil-fuel infrastructure at home In 2016, just after he was elected, Houston Mayor Sylvester Turner gave a rousing speech calling for a ?paradigm shift? in the city?s transportation priorities?moving away from building highways that serve single-occupant vehicles.
Houston?s transportation problems have gotten worse since Turner made that speech. Emissions from driving have gone up 127 percent in Houston?s metro area since 1990, with the most dramatic increases in auto emissions occurring in the last few years.
But earlier this year, Turner endorsed the North Houston Highway Improvement Project, a plan to spend a jaw-dropping $7 billion to widen 25 miles of highway in the city. Turner?s about-face was even more surprising given that, in 2017, he was made co-chair of the Climate Mayors, a group of 438 U.S. mayors who have pledged to uphold the Paris Agreement?s goals to keep warming to 1.5 degrees Celsius after the U.S. government backed out.
Last week, the United Nations Environment Program (UNEP) said dramatic actions must be taken in order to have a fighting chance to achieve that 1.5-degree target?starting with reducing carbon emissions by a minimum of 7.6 percent each year.

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