Car-free corridors, a carbon tax and a charging station for every hungry vehicle.

Solar panels, smart meters galore and a farewell to natural gas and free parking.

The ideas for transforming Palo Alto into a greener and more resilient community came flying from every direction at the city's Sustainability Summit, which brought a crowd of almost 300 residents on Sunday to Jordan Middle School.

Organized by Gil Friend, the city's chief sustainability officer, the summit featured a TED-style talk from a retired Marine who advised the Joint Chief of Staff on a "Grand Strategy" around sustainability; a presentation about the city's new Sustainability and Climate Action Plan; and a group exercise in which attendees broke into groups and discussed potential goals – as well as anticipated obstacles – in the city's renewed charge to cut carbon.

In his introductory comments, Mayor Pat Burt called the event "perhaps the largest and most important environmental gathering in Palo Alto's history."

"Your guidance and commitment today will help determine whether we will pass on a sustainable community to our children and their children," Burt said.

The event took place at a time when the City Council is preparing to renew its vows to cut carbon. The City Council had adopted its last Climate Action Plan in 2007, becoming one of five cities in the nation to do so, according to Friend. On Monday night, the City Council is set to discuss the new Sustainability and Climate Action Plan, which will set out new goals and strategies for achieving them. Specifically, it will recommend a goal of slashing emissions by 80 percent by 2030. This would be well ahead of California's aspirational goal of reducing emissions by 80 percent by 2050.

Friend cited the city's recent accomplishments in promoting carbon reduction, including a carbon-neutral electric portfolio and a green-building ordinance that goes well beyond state requirements for sustainable construction.

"California leads the country and we're a step ahead of that," Friend said. "Not just because we can, but because it makes good sense."

The event began with a video presentation from Mark Mykelby, a retired Marine colonel who served as an advisor to the Joint Chief of Staff and who champions the idea of a national strategy built around sustainability. Initially scheduled to give the keynote address at the summit, Mykleby attended the event via videoconference after snowstorms impacted his travel plans. After a video of his talk screened, Mykleby was digitally transported to Jordan for a round of questions and answers.

Mykelby made a case in his presentation for a more urgent response to the globe's growing population and the corresponding depletion of resources. By the middle of the century, he said, the world will have to fold in 9 billion people. In places like China, water supply will be strained by population growth. And food continues to grow more expensive, he said.

"We are depleting the ecosystem at a rate we've never seen before," Mykleby said. "We just don't have enough s--t in the world to support what we're doing. Come to grips with that!"

He encouraged a strategy built around three main pillars: walkable communities, regenerative agriculture and a productivity revolution in manufacturing and energy.

In his live remarks to the enthusiastic Palo Alto crowd, Mykleby lauded the city for its efforts on sustainability and for putting together the Sunday summit.

"You're one of the examples I like to use as to what it means to be citizens and get stuff done," Mykleby said. "What you're doing is real and important."

Then the crowd got to work. Over a series of rounds, groups gathered around tables and debated a series of broad questions: What if Palo Alto was leading the way? What obstacles might we face and how can we overcome them? If our success was completely guaranteed, what bold steps might we choose?

Each group was assigned a category to focus on: either transportation, energy, water or the natural environment. After a round of brainstorming, attendees would rotate into new groups and grapple with new topics.

The answers were all over the map. Sven Thesen, a leading proponent of renewable energy, cited as one of his group's ideas an underground transportation system stretching from Marin County to San Jose, with high travel speeds and numerous stops along the way. Arthur Keller, a former long-time member of the city's Planning Transportation Commission, proposed more charging stations for electric vehicles.

"Several generations ago, we talked about having a chicken in every pot," Keller said, alluding to the famous slogan of Herbert Hoover. "It would be nice to talk about having an EV charger in every parking space."

Other attendees focused on electricity, water and building construction. Given the city's carbon-neutral electricity supply, the idea of switching homes from natural gas to electricity proved generally popular. Because of the high costs of changing the heating systems, Friend said staff is thinking about promoting this switch through attrition and replacement.

One attendee proposed keeping University Avenue free of cars for the entire summer. Another lobbied for making parking more expensive. Another proposed a carbon tax, an idea that staff considered but does not expect to include in the new plan.

Others ideas are even longer shots. Will all of Palo Alto go vegan? Will the city's groundwater become a significant source of hydroelectric power? Highly unlikely.

But while behavior preferences and political (not to mention, appreciation of meat and cheese) will undoubtedly limit how far the city goes with the new sustainability plan, money doesn't have to, Friend argued. His message, often reiterated throughout the Summit, was that "done well, sustainability is a damn good investment."

"It's not a matter of trading off money and environmental benefits," Friend said. "It's a matter of designing programs that pan out."