“When you look at the huge threats we face as a planet now, they are all ecologically related,” he said. “When a society outstrips its resource base and leadership fails to imagine new ways, it crumbles. So how we play this game is going to determine where we end up.”

His solution — slightly dumbed down for those of us whose forte is not science — goes like this: Modern petroleum-fueled agriculture, focused on industrial efficiencies and profits, has pumped up to 70 percent of the soil’s carbon into the atmosphere. That’s left us with a “legacy load” of 1,000 gigatons of CO2 in the air that would linger even if all emissions stopped today.

All that carbon dioxide in the atmosphere overheats the planet, whereas CO2 in the ground is beneficial, increasing the fertility of the soil, feeding plants, nurturing bigger and better crops and decreasing ocean acidification. So if we can “draw down” the carbon in the atmosphere and sequester it in the soil, we can solve two problems at once — stopping the warming and feeding the masses.

The best way to make that happen, Tickell said, is through regenerative farming, which is based on the simple and ancient principle that if you nurture and protect the soil, it will reciprocate with bountiful crops. Using methods like composting, biodiversity and perennial plants rather than tilling, monocultures and overuse of chemicals, those harvests will not only produce more food for a growing world population but keep CO2 in the ground, where it belongs. “Problem solved,” Tickell said, smiling.

“This is the ‘do less harm’ idea. The majority of CO2 is in the soil, and if we remove it, we’ve reduced the amount of land available to make food. Where does it go? The majority goes into the air. Yet every year, the soil almost sucks down all the CO2 we put in the atmosphere. We can’t put more of our legacy load in oceans or the atmosphere, we can only put it in the soil. And the soil is very large place to put the load because plants take in CO2.”

Researchers have estimated we could sequester 6 gigatons of carbon dioxide a year just by planting the right kind of crops, more than compensating for the 4.3 gigatons humans are currently emitting. So we could not only stop temperatures from rising, we could even make a dent in the damage we’ve already done.

“We’re not just looking at the changing of a desert into an ecosystem,” Tickell said, “we’re looking at reversing global warming.”

Is all of this realistic? Only if farmers and governments get on board and people change the way they eat, shop and live. For the average Joe it would mean buying local, composting, reducing waste, planting trees and supporting governmental changes in food production. It doesn’t, however, mean you have to go vegan; healthy soil and sustainable ecological farming are compatible with raising animals, when cattle graze the natural landscape rather than bulk up on grain in feedlots.

Tickell is finishing a film, “Life After Carbon,” due to be released before the 2020 election (“I promise”). It focuses on members of the Millennial and Gen Z generations now entering politics who he believes will “seize the moral authority” and force a change in approach. It’s up to them to “do everything possible to make it happen,” he said, while it’s up to the rest of us to mentor, get out of the way and “not be negative about it.”

Tickell’s talk began against a backdrop projection of the famous “Earthrise” photo, the first color image of our planet taken from space during the Apollo 8 mission in 1968. He called the reaction to the picture a “pivotal moment.”

“Before this time, we had no context of all being together on one blue ball hurtling through space,” he said. “Then, suddenly, there was the immutable proof that no matter who we are, we are together.”

“We don’t have a term for it yet — it’s aspirational beyond capitalism, beyond socialism, beyond border,” he said. “We want sustainability, to be done with the destructive economy. But what we’re talking about now is an economy of abundance, something so hard to conceptualize because we’ve never had it. Allow yourself to believe there is the possibility that the future might just work out.”

Contact columnist Carrie Seidman at 941-361-4834 or carrie.seidman@heraldtribune.com. Follow her on Twitter@CarrieSeidman and Facebook at facebook.com/cseidman.