Using more renewable energy is one way to help bring down greenhouse-gas emissions. | Photo by Caitlin Bowling

Louisville Metro Government on Friday said that it wanted to cut by 80 percent the amount of heat-trapping pollution the city sends skyward in 2050, at the same time saying that it had overstated an earlier drop in greenhouse-gas emissions.

Setting the target is one big step toward meeting a pledge called the Global Covenant of Mayors for Climate & Energy that Greg Fischer signed in May 2016. Next comes the tougher job of working with residents and businesses to form a strategy by the end of 2019 to meet the goal.

The covenant is one of several commitments to fight global warming that Fischer has made since taking office in 2011. Louisville joins Cincinnati, Atlanta, Denver and other cities in setting the 80 percent target.

“Many of our city’s largest businesses already have adopted corporate practices and goals that will help us move the needle, and we urge individuals to do their part as well,” Fischer said in a news release. “It will take all of us to achieve this very ambitious goal.”

Mayor Greg Fischer

A cut of 80 percent would be down from a “business-as-usual” forecast that takes into account projected economic and population growth. Meeting the target would mean Louisville emits around 3.7 million metric tons of CO2 equivalent in 2050, down 77 percent from around 16 million metric tons in 2016 and 79 percent from 2010.

The decline would be in so-called core greenhouse-gas emissions, which the city says are those it has the greatest opportunity to influence, such as from energy use in buildings and in-town transportation.

Louisville Metro Director of Sustainability Maria Koetter said a further shift in the utility sector toward greener energy would be critical to meeting the target.

“Since we know that is going to happen, that gives us the confidence that we can set the goal and achieve it,” she said. “That energy piece is going to be the biggest part.”

LG&E and KU’s switch to burning natural gas instead of coal at its Cane Run power plant accounted for the bulk of a 10.1 percent drop in greenhouse-gas emissions between 2010 and 2016. Using more natural gas would lower the carbon footprint further, as would mixing in more renewable energy, boosting building and industrial efficiency and cutting emissions from vehicles, Koetter added.

The 10.1 percent reported drop is smaller than the 16.9 percent decline the city reported in a draft inventory released a year ago. That draft had overcounted the benefit of the Cane Run fuel switch, Koetter said, prompting the revision.

Environmental groups are pressing Metro lawmakers to commit to abandoning fossil fuels and to set a goal of 100 percent renewable-energy use by city government by 2030, and by the entire metro area by 2035.

“What this all comes down to is how many resources is Metro government willing to commit?” said Sarah Lynn Cunningham, executive director of the Louisville Climate Action Network. If people aren’t put in charge of making sure each segment of the economy is working toward the target, “it’s not going to happen.”

Separately, the bicycle-shop owner Jackie Green, who ran for mayor on a platform of fighting climate change, said he delivered to Fischer’s office on Friday a letter calling for an end to the city’s dependence on coal and gas, and to overhaul transportation and land use. Green said letter signers plan to return to Fischer’s office on or near the 22nd of each month — with Earth Day falling on April 22 — to ask for a progress report.

More than half the “core” emissions — 54 percent in 2016 — tallied in the city’s inventory come from residential, commercial and institutional buildings, with on-road transportation accounting for about 17 percent. Because cutting these will require individuals and businesses to change their ways, the city is asking residents to fill out a survey to find out how likely people are to take certain pollution-cutting actions, like riding a bicycle or buying a programmable thermostat.

The breakdown of Louisville’s 2016 greenhouse-gas emissions.| Louisville Metro

“We are going to ask the community what they want to see,” Koetter said. “We need to strike that balance between incentives and policy.”

The city plans meetings with community groups, with the first one scheduled for the Rubbertown Community Advisory Council on Jan. 10, followed by the 100 Resilient Cities Work Group on Jan. 30.

The 80 percent target falls short of what a key international body says is required globally to stave off the worst effects of climate change. In an October report, the U.N.-led Intergovernmental Panel on Climate Change said keeping global warming to a rise of 1.5 degrees Celsius above pre-industrial levels would require cutting greenhouse-gas emissions by about 45 percent from 2010 levels by 2030, and eliminating them by around 2050.

“We will do our very best and setting this reduction goal and identifying the steps to achieve it will be a great first step,” Koetter said. “Then, if things happen along the way that will allow us to do even more than an 80 percent reduction, then we would be excited to do that.”

An LG&E and KU spokeswoman said in an emailed statement that it looked like the city was taking a “reasonable approach” to cutting emissions, adding the target aligns with parent company PPL Corp.’s aim to reduce its overall CO2 emissions by 70 percent from 2010 levels by 2050. The company plans to retire 272 megawatts of coal-fired generation at its E.W. Brown facility early next year, among other moves, she said.

The Global Covenant of Mayors was just one of several agreements Fischer has signed pledging action to fight climate change, which is expected to hit Louisville especially hard, owing in part to its expanses of asphalt and shrinking tree cover.

Shortly after taking office in 2011, Fischer renewed predecessor Jerry Abramson’s commitment to cut emissions in line with the Kyoto Protocol. Last year, he signed the “We’re Still In” letter pledging commitment to the goals of the Paris Agreement after President Donald Trump pulled the U.S. from the pact. A year ago, Fischer joined other U.S. mayors pledging pollution cuts in the Chicago Climate Charter.

This article has been updated with comment from LG&E and the Louisville Climate Action Network.