Bloomberg claims gains on carbon footprint as mayor

As Michael Bloomberg campaigns for president, he reminds Democratic primary voters about what he did as New York City mayor for 12 years. That includes his efforts to combat climate change, work that he continued after leaving office.    

"And I might point out when it comes to climate change, we cut New York City’s carbon footprint twice as much as the rest of the country, and we can do that again," Bloomberg told a crowd at the opening of his campaign headquarters in Charlotte, N.C.. "And we have to do that, or we just don’t have a future."

We wondered if Bloomberg’s claim about New York City’s smaller carbon footprint is accurate. 

For evidence of his claim, campaign spokeswoman Julie Wood sent us a city report published in 2017 and data from the U.S. Environmental Protection Agency from 2002 to 2013, the period  Bloomberg served as mayor. 

The city report, released under Mayor Bill DeBlasio’s administration, shows the city reduced greenhouse gas emissions by 14.8 percent in 2015 compared with 2005 levels. The city began measuring its carbon footprint under Bloomberg, with the earliest data from 2005.

"Much of these reductions were achieved early on, largely as a result of power plants switching their fuel source from coal to natural gas - a less carbon-intensive energy source; and through the construction of new, highly efficient natural gas power plants, both within and outside the city," analysts wrote in "Inventory of New York City Greenhouse Gas Emissions in 2015," published in April 2017. 

The city reports its analysis includes all direct and indirect greenhouse gas emissions from energy used by buildings and other stationary sources, natural gas distribution within the city, on-road transportation, railways, marine navigation, and aviation within the city’s borders, as well as emissions from wastewater treatment and solid waste from the city, even if it is  disposed elsewhere.    

For the country as a whole, data from the U.S. Environmental Protection Agency’s Greenhouse Gas Inventory Data Explorer show that greenhouse gas emissions decreased 6.8 percent between 2002 and 2013, when Bloomberg was mayor. 

John Reilly, co-director of the Joint Program on the Science and Policy of Global Change at Massachusetts Institute of Technology, called the city’s report a "carefully done effort." Also, the federal data the Bloomberg campaign directed us to is the "authoritative accounting" of greenhouse gas emissions for the United States, Reilly said. 

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Reilly called Bloomberg’s statement "basically accurate." 

But he added some observers could take issue with the claim. He said that "carbon footprint" is more often associated with a broader definition than the one the city uses. The broader definition includes the full life cycle of emissions of all goods consumed in the city, such as emissions associated with steel used to produce automobiles sold or used in the city, and methane emissions from cattle raised to produce beef eaten in the city. However, these emissions are difficult to account for accurately, much less control. For these reasons, Reilly said that the city is better off analyzing its emissions as it does, focusing on the narrower definition.     

Observers could also take issue with Bloomberg calling New York City’s emissions lower than the "rest of the country." The federal data includes New York City, not the country minus the city. Other places in the United States also performed better than New York City, he said.

Bloomberg tells a "legitimate story" that New York City ranks among the nation’s leaders for taking climate seriously, Reilly said. The city emerged as a leader because of Bloomberg’s focus on the issue as mayor, and the city makes a serious effort to assess its progress, he said. 

We consulted other experts who had other reactions. On the left, Greenpeace noted that the 6.8 percent drop in emissions nationwide covered a different period than the New York City report, which includes years 2014 and 2015, beyond Bloomberg’s mayoral tenure. 

We were curious about this as well, and we found the most recent city data show that in Bloomberg’s last year as mayor, 2013, there was a 12.8 percent reduction in greenhouse gas emissions compared with 2005 levels. While close, New York City's reduction between 2005 and 2013 is not quite twice as much as the country's 6.8 percent reduction between 2002 and 2013.    

On the right, the conservative Manhattan Institute connected us with an adjunct fellow there, energy industry consultant Jonathan Lesser, who said that Bloomberg’s claim is "irrelevant - totally, utterly and completely," and that emissions reductions in New York City are "meaningless from the standpoint of global climate change." He also noted that the city report does not go back to Bloomberg’s earliest years in office.   

Bloomberg said his administration cut the city’s carbon footprint twice as much as the rest of the country. 

Bloomberg was in office between 2002 and 2013. During a somewhat different timeframe, 2005 to 2013, the city’s greenhouse gas emissions fell 12.8 percent. During the years of Bloomberg’s tenure, greenhouse gases fell nationally by 6.8 percent. 

We rate his claim Mostly True.