With or without significant federal support, reducing greenhouse gas emissions will require major private investment, as it has here in Iowa, and ambitious private-public initiatives from mayors and governors. We need to activate a new era of “regenerative” cities and states.

California’s recent move to reduce its carbon emissions by 40 percent below 1990 levels by 2030 is a hopeful shift that other cities and states should emulate. This would involve setting high benchmarks for developing green enterprise zones, renewable energy, cultivating food locally, restoring biodiversity, planting more trees and emphasizing walkability, low-carbon transportation and zero waste.

Following this regenerative approach, the Australian city of Adelaide reduced its carbon emissions by 20 percent from 2007 to 2013, even as the population grew by 27 percent and the economy increased by 28 percent. The city experienced a boom in green jobs, the development of walkable neighborhoods powered by solar energy, the conversion of urban waste to compost and a revamped local food industry. The city also planted three million trees to absorb carbon dioxide.

Over 10,000 climate initiatives are underway in cities worldwide, according to the C40 Cities Climate Leadership Group, which represents 80 major cities. In nearby Des Moines, for instance, Mayor Frank Cownie recently committed the city to reducing its energy consumption 50 percent by 2030 and becoming “carbon neutral” by 2050.

Initiatives like those have become a “fill the potholes” reality for many mayors, regardless of political games in Washington. In San Diego, the Republican mayor, Kevin Faulconer, helped to push through a climate action plan that commits the city to 100 percent renewable energy by 2035. Other cities are following his lead.

“Dull, inert cities, it is true, do contain the seeds of their own destruction and little else,” the urban visionary Jane Jacobs wrote. “But lively, diverse, intense cities contain the seeds of their own regeneration, with energy enough to carry over for problems and needs outside themselves.”

In an age of climate change, and a possible shift in the federal government’s priority on climate action, never have those words been truer.