After the Cop26 conference ended in Glasgow, many activists and climate scientists felt the agreement didn't go far enough and that the US government was among those who had not backed strong words with enough actual deeds.
But action on a smaller level in the US - in cities and states - is gaining traction and beginning to make a significant difference. Smaller-scale initiatives to cut emissions have been the significant way that America has made climate progress in the last few years, in the absence of stronger federal leadership.
Researchers at the Brookings Institution calculated that in 2018, these climate action plans generated 6% emissions savings for the country - the equivalent of removing 79m cars from the road that year.
"These are significant benefits," says Mark Muro, a senior fellow and policy director at Brookings Metro. "None of this is large enough, but they add up to a meaningful trend of emissions reductions. Those are real contributions."
Even at the climate meeting there was an increased appreciation of city-based climate action plans - Cop26 featured a whole day focused on what regions and cities can do, Muro points out. In the US, 45 of the 100 biggest metro areas have pledged to cut carbon emissions. "There is no doubt that cities are crucial places where emissions can be curtailed and better solutions worked out."
Cities are on the frontlines of action plans, but also of the direct effects of the climate crisis, including power outages, fires and floods. That makes them more likely to take quick action. People moving due to climate change will also primarily be moving to cities, putting extra importance on their ability to plan for the future. Joe Biden's new infrastructure bill will pour tens of billions of dollars into funding for climate-related projects.
For example, San Diego recently created a plan to become more climate resilient - one that prioritizes the needs of the most climate-vulnerable. It would plant more trees, expand parks in low-income areas and update public transit.
"As our country has witnessed in recent months, extreme weather driven by a changing climate can have devastating effects," Todd Gloria, San Diego's mayor, wrote in the plan. "While these threats aren't new to San Diego, science tells us that climate change is making these events more frequent and intense. The cost of inaction would be far greater than investing in our future."
In Austin, Texas, the city successfully decreased its building emissions by 20% despite a booming population, but experienced an increase in transportation emissions between 2010 and 2018. The city hopes to electrify their municipal vehicle fleet in the near future.
Pittsburgh finalized a plan this week to increase energy efficiency across the city and reduce emissions by 50% by 2030, pushed forward by the Glasgow conference, which the mayor attended.
Ambitious climate action plans are crucial roadmaps, but they can be based on faulty assumptions. Muro's research shows such plans have been a mixed bag in terms of actually delivering emissions reductions. "They make large promises that aren't necessarily backed up by hard work of delivery," he says. "It's a good time to refocus and really think about how to make these work better."
For one thing, more cities need plans: in 2018, Muro and his colleagues tallied that only 45 of the largest 100 cities in the US had such plans. Smaller metros often don't have any plans in place. Some regions of the redder states may struggle to implement climate strategies - though Muro says that when they package climate strategies as part of a data-driven good government effort, it is less fraught with politics.
Also, the quality of the pledges is questionable - they can sometimes be infeasible if they don't have control over a power plant that produces emissions in their region, or if they aren't able to enforce rules that they propose due to other laws. Also, with the exception of cities in California, city action plans' efforts to reduce greenhouse gas emissions are mostly non-binding.
Cities and states can learn from each other, rather than reinventing the wheel each time. Groups like C40 cities - a global network of mayors taking action on the climate crisis - can make it easier to share data and strategies. Pooling data can also lower the cost of accountability.
Coming out of Cop26, there is a recognition of the extreme urgency of the moment and the importance of cities as one source of progress, Muro says. "Cities need to couple their large aspirations with grittier implementation now."