How hard is it to reduce greenhouse gas emissions? Just look at Boulder.

If anyone in the United States could make it look easy to reduce greenhouse gas emissions and help fight global warming, it should be the People’s Republic of Boulder, right? 

Turns out, cutting carbon is hard. Even for the city of Boulder. And since Boulder has set audacious goals for itself, their year-end reports can look pretty brutal. 

Boulder was one of the first cities in the country to set its own goal for cutting carbon, in 2006. Then, in 2021, Boulder doubled down and said it would try to cut its local carbon footprint 70% by 2030, from a very ambitious new baseline of 2018 emissions levels. Remember, those 2018 levels already represented significant cuts from the 2005 baseline that many government entities use, so Boulder was giving up a big head start. 

How are they doing? A newly updated carbon dashboard for Boulder says “communitywide emissions decreased 2% from 2021 and were 18% below the 2018 baseline.”

That’s a nice number, representing millions of tons of carbon removal. But it’s a long way from 18% to 70%, with only six years left to go. Boulder’s even bigger goal is to be net zero on carbon emissions by 2035. And the city doesn’t have the opportunity of shutting down a coal-fired power plant within its boundaries to get a big numbers boost. 

“We continue to make progress,” Boulder sustainability senior manager Carolyn Elam said in an interview. “I think we continue to have to accelerate our progress if we’re going to hit our goal. Seventy percent is … really hard.”

Other cities in Colorado and elsewhere have set their own carbon goals to drive local policy while signaling to state and federal leaders that there’s grassroots support for combating climate change. 

As part of Denver voters approving a new climate-dedicated sales tax in 2020, city leaders and task force advisers set a goal of ending 100% of greenhouse gas emissions by 2040. The goals included the interim step of “a science-based target of a 65% reduction in emissions by 2030 from a 2019 baseline.” 

Milwaukee has set goals of 45% greenhouse gas reductions by 2030, and going net zero by 2050. 

To get at its carbon emissions, Boulder adds up the carbon produced from all public and private categories such as its portion of Xcel Energy’s sales of power in the city, the transportation emissions of cars and trucks inside the boundaries, natural gas burned for building heat and stoves, and more. Boulder gains as Xcel cleans up its statewide electricity generation with solar and wind, and city officials encourage Xcel’s transformation, but that’s only one portion. 

“The biggest thing that we’d have to do to influence that number is just transition the majority of our buildings away from natural gas,” Elam said. Chances to do that are limited somewhat by the fact Boulder has almost no residential construction going on. Banning new natural gas connections, as many cities have considered, doesn’t move the needle if there are no new houses going up. 

But the city is working with partners to emphasize rebates and other opportunities for homeowners and landlords to replace gas furnaces with electric heat pumps and other alternatives, Elam said. 

On transportation, Boulder also has little control over how quickly drivers transition to electric cars, or the private truck fleets that crisscross the city. But the city is supporting turnover in local bus fleets to clean electric, and is always seeking ways to reduce vehicle miles traveled, Elam said. 

Denver’s goals also outline the main strategies for achieving them, including “fuel-switching” for residential and commercial buildings and completely decarbonizing transportation by 2050. Achieving net zero would require building owners to accelerate the switch from natural gas as a heating and cooking source to clean and efficient electric heat pumps and induction stove tops. Cleaning up the vehicles crisscrossing Denver would mean all-electric or hydrogen-fuel buses for RTD, diesel delivery trucks switching to batteries or hydrogen, and an all-electric passenger vehicle fleet. 

Denver’s climate office, charged with spending the $40 million-plus in annual revenue from the 2020 dedicated climate sales tax, also believes small solar projects can add up to a big part of the solution, according to office director Liz Babcock. The climate office has unveiled a series of parking lot canopies at Denver Public Schools that serve multiple purposes of generating electricity, providing shade in urban heat islands, and powering electric car chargers. 

Another big target for Boulder is waste, with the goal of reducing the carbon emissions associated with sending items to a landfill that could otherwise have a useful, emissions-reducing second life. Successfully reusing much of Boulder’s former community hospital during a 2023 deconstruction was a watershed moment, Elam said. 

Boulder has recently begun an even more ambitious education effort by adding a second, global carbon footprint for the city, counting up carbon created from goods made outside Boulder and brought in as retail sales, for example. That larger carbon footprint from all goods and services used in the city can be daunting for many people to accept. 

But sustainability leaders shoot for learning, not despair, Elam said. She recalls early debates about Xcel in Colorado, when regulators wondered if a 5% goal for renewable generation was impossibly high. Those same regulators are now entertaining studies about whether Xcel will hit 80% or 85% renewable generation by the 2030 target. 

“We often are surprised at how far we can go. And we often shoot past some of those targets. So I’m actually still optimistic about our goals,” Elam said.

 “I think they’re the right goals, to guide our community and to really set that bar out there for people to think about.”