With sea level rise already lapping at its door, the city of Miami made its first significant commitment to address the root cause of climate change, not just the symptoms.

The city government plans to go carbon neutral by 2050, a pledge that will change everything from what city employees drive to how the city builds and how it powers itself.

Miami became the first city in Florida and 96th in the world to join C40 Cities, an international climate organization that helps cities lower their carbon footprint. Mayor Francis Suarez, who signed the agreement, called it a moral imperative for the city to cut its emissions.

“If we really want to be here forever we can’t just react to what mother nature is doing,” he said. “We have to do everything in our power not to make matters worse, but to make matters better.”

Exactly how the city plans to go carbon neutral, a hefty goal for a large and car-centric community, comes later. Miami’s Climate Ready Plan will be released soon, and it tackles broad actions the city can take, like switching out gas-powered city cars for electric vehicles, installing more solar panels and enforcing energy efficiency in city buildings.

In recent years, Miami has largely chosen to address the two feet of sea level rise expected by 2060 with adaptation measures that address the effects of climate change, such as flooded streets, rising groundwater and hotter days. The force driving them — excess greenhouse gasses in the atmosphere — has not been on the agenda.

Under activist pressure, that is starting to change. Miami just declared a “climate emergency,” a symbolic gesture at the city’s increased focus on the topic. Advocates have since pressed the city to commit to cutting its carbon footprint.

Susan Glickman, Florida director for the Southern Alliance for Clean Energy, called it a significant goal for the city.

“It’s key to have local governments commit to meaningful targets to move the needle backwards on carbon emissions,” she said. “It’s key to have cities like Miami show leadership. It shows the state of Florida, that has yet to take on any targets toward carbon emissions, that it’s possible and it’s important to do to avoid the worst implication of climate change.”

Emily Gorman, chair of the Miami Climate Alliance, said her organization is more skeptical about the city’s plans. They’re waiting to see the exact steps the city plans to take.

“We are obviously very hopeful and glad to see the mayor is interested in bold climate action,” she said. “But frankly, implementation is the nature of true leadership.”

She hopes to see the city commit to 100% renewable energy, like South Miami had pledged to do. That doesn’t include nuclear power from Turkey Point, which provides energy for much of South Florida. Nuclear power doesn’t create emissions and is considered renewable energy, but some environmentalists like Gorman think the safety and pollution concerns declassify it as “clean energy.”

Another priority for activists: that the transition to renewable energy doesn’t just benefit the rich.

Gilbert said the city plans to work with C40 to come up with policies that both lower emissions and provide jobs and business opportunities for low-income parts of the community.

“It’s important to frame our actions in how they’re going to give us an economic return on investment and provide a source of living-wage jobs,” she said. “We’re not going to be able to spend a lot of money on something that only provides carbon mitigation. It’s got to provide other returns.”

Laura Jay, deputy regional director for C40’s North America program, said her team helps cities put numbers on the side benefits of mitigation, like the health benefits of cleaner air or the new jobs a solar farm could provide. That makes it easier for mayors to pitch policies to their commissions.

“That helps bring cities to the table and showcase their leadership,” Jay said.

They also connect staffers at cities across the globe to share success stories or tips. C40 tracks cities — like Boston, Paris and LA — to see if they meet their commitments.

Miami’s last attempt to cut its emissions didn’t go well. A 2008 plan to address climate change and the city’s emissions called for Miami to cut emissions 25% below 2006 levels by the year 2020, to 3.6 million metric tons. The plan also called for annual updates on the city’s progress.

Then came a recession and a new mayor.

“The mayor and manager at that time decided that was not the priority,” Gilbert said.

In the meantime, Gilbert said, the city did a few things to lower its carbon footprint, like making older buildings more energy-efficient and switching park lighting to LEDs. Last year, the city swapped out 90 gas-powered cars in its fleet for electric hybrids.

But exactly how much better or worse the city’s carbon emissions became in the last decade is unclear.

Miami is in the process of accounting for its greenhouse gas emissions now and hopes to be done by April. After that data is available, Gilbert said, the city will set specific, new targets for reductions.

Miami-Dade County set its own emissions goals shortly after Miami first did, in 2010. The county’s Greenprint plan called for a 10% reduction from 2008 levels by 2015.

“The County did not achieve this goal. In fact, emissions increased over this period,” wrote Miami-Dade’s Chief Resilience Officer, Jim Murley, in a statement. That came from a combination of more people driving more cars, more aviation emissions and higher emissions from industrial activity, he said.

So far the county has tackled its emissions with a new purchase of 33 electric buses and various energy efficiency programs, including one that requires buildings over 20,000 square feet to benchmark their use of electricity.

“In order to reach the 2050 goal of an 80% reduction, the community will need to implement meaningful resource conservation measures that include fuel, energy and waste reduction as well as investments in renewable energy like solar and transitioning to more electric vehicles countywide,” he said.