Thinking about Earth Day, I did a Google search for “global warming solutions.” Up popped a slew of “what you can do” lists from leading scientific and environmental organizations. When I dug in, however, I found the suggestions rather general — “reduce emissions,” “stop deforestation,” “consume less,” “be efficient,” “eat smart.” The lists were also mainly about what we ought to do, rather than about what people are doing, where we are seeing progress and how we might build on those opportunities. I wondered: How do we translate these imperatives into action for people in different fields and positions?

One important source of guidance is Project Drawdown, a global coalition of researchers, scientists, economists and others, that, in recent years, has built a model to evaluate and rank the top active solutions to global warming, based on their actual impact on greenhouse gas emissions.

I spoke with Project Drawdown’s executive director, the environmentalist and author Paul Hawken, about this initiative and where he sees it heading.

David Bornstein: When did you get the idea for Project Drawdown?

Paul Hawken: Back in 2001, the Carbon Mitigation Initiative came out of Princeton with the famous eight global wedges comprised of 15 solutions that if adopted would stabilize emissions by 2050. I didn’t share the same enthusiasm as other environmentalists because 11 of the 15 solutions could only be implemented by the boards of directors of very conservative, large corporations, and every solution was financially underwater.

In 2013, Bill McKibben wrote his piece in Rolling Stone “Global Warming’s Terrifying New Math,” where he showed that if we burned all the coal, gas and oil that was in reserve on fossil fuel companies’ balance sheets, we’d be Venus. At that time, activist friends came to me and said: “It’s game over. There’s nothing that can be done.”

D.B.: Clearly you didn’t think it was game over.

P.H.: I did not. I asked colleagues: “Do we actually know what we can do with respect to addressing global warming? Can we make a list of things that we are already doing and measure their greenhouse gas impact, along with the cost or savings if any?”

I gathered a small group of friends to see if we could map, measure and model the 100 most substantive solutions to reverse global warming. I wanted to name the goal: “Drawdown” — the first time on a year-to-year basis that greenhouse gases peak and go down. It is the only goal that makes sense for humanity and civilization. And larger goals create a greater sense of possibility.

D.B.: How did you figure out the solutions and rankings?

P.H.: We put the word out to universities around the world, seeking research fellows who would do a master’s thesis on one of the solutions for the princely sum of $1,000. We were overwhelmed with applications from Rhodes scholars, Fulbright scholars and White House fellows. We chose nearly 70 fellows. We used Zoom night and day to collaborate with colleagues from 22 countries. We added 120 advisers and 40 outside expert scientific reviewers of the model itself.

D.B.: How did you decide which solutions to include?

P.H.: We modeled solutions that are in place, practiced, understood and about which there is peer-reviewed science with respect to impact and robust economic data with respect to cost. To source economic data, we used highly respected international institutions, including the International Energy Agency, World Bank, U.N. Food and Agriculture Organization, IPCC [Intergovernmental Panel on Climate Change] and Bloomberg Energy. We erred on the side of conservatism on all data.

D.B.: How did the process help you to think differently about global warming?

P.H.: We constantly hear that global warming is an energy problem, that the solutions are solar, wind and electric vehicles. For the individual, that message sounds like I hope “they” do it. There’s a belief that there’re only a few things individuals can do beyond recycling, riding a bike and eating less meat. In fact, there’s an extraordinary diversity of solutions to global warming that are at hand, being implemented and scaling. I don’t think people, politicians and businesspeople know that. Clean energy is the crucial solution to be sure, but there’s much more we can do.

D.B.: Like what?

P.H.: Two of the top four solutions individuals can practice every day. No. 3 is reduced food waste, which particularly applies to America, where we waste 133 billion pounds of food a year — close to a third of the food supply. That is a conservative estimate. In our model we didn’t include the methane emissions caused by landfilling our food because we couldn’t get the data — and methane is 28 to 36 times more powerful in global warming potential than carbon dioxide.

The No. 4 solution is a plant-rich diet. This means reducing overconsumption of protein to a healthy level — about 50 to 55 grams a day instead of 90 to 100 or more, and shifting a proportion of that reduced intake to plant proteins. It doesn’t mean being a vegan or vegetarian; it means more plants. You choose which diet you want. Levels of protein that are medically healthier for you are healthier for the planet and atmosphere, too.

D.B.: Can you talk about the No. 1 solution? I was surprised to see that it was “‘refrigerant management.”

P.H.: We were, too. The hydrochlorofluorocarbon gases (HFCs) used in refrigerants that replaced chlorofluorocarbons (CFCs), which were destroying the ozone layer, are anywhere from 146 to 12,500 times more powerful than carbon dioxide in their global warming potential. Poorly maintained air-conditioners and refrigerators leak HFCs. When air-conditioners and refrigerators are disposed of or recycled, the refrigerants can escape into the air. We do a pretty good job preventing this in the United States, and the European Union does even better, but in Asia and Africa, HFCs are allowed to escape and have a huge impact.

D.B.: What else caught you by surprise?

P.H.: Over all, we were surprised that the largest sector was food. Agriculture, food waste and diet, food production and distribution of food, holistic grazing. We didn’t see that coming. It’s larger than the electrical generation sector.

And the overall ranking of the solutions shocked us. If you had asked every person at COP21 in Paris (us included) to name the top 10 solutions in any order, I don’t believe anyone would have gotten it even close. That is still true. After 50 years of global warming being in the public sphere, we didn’t know the top solutions to reversing it. And there’s a reason: We never measured and modeled the top solutions. Instead, sincere, well-meaning people profess their beliefs. You have a prominent scientist asserting that if we don’t go all in with nuclear power, we’re toast. Vastly untrue. You have journalists assuring us that if we go 100 percent solar, we’ll stabilize emissions. That’s a scientific howler, too. People who are earnestly guiding us to climatic stability have not done the math. That’s all we do at Project Drawdown: math.

What Drawdown reveals is not “our” plan. It seems that the collective wisdom of humanity has a plan. Drawdown is a reflection of what the world knows and what it is actually doing. None of the millions of data points modeled was our data.

D.B.: I suspect that few people will have heard of solution No. 9: silvopasture. What’s that?

P.H.: The meaning is in the words “silvo” and “pasture” — tree and pasture. It is the combination of woodland trees and forage for domesticated animals. It’s been practiced for 3,000 years. It’s accelerating in growth and understanding today. The dynamic relationship between pasture, grassland and trees creates greater carbon sequestration, more water retention, less if any erosion, and more biodiversity. You have more birds, which is good for controlling insects. You have more microbiota creating healthier soil. And it produces more income for the farmer. It’s being advanced by agroforestry associations around the world.

D.B.: When people ask, “What should I do?” what do you say?

P.H.: A primary goal of Drawdown is to help people who feel overwhelmed by gloom-and-doom messages see that reversing global warming is bursting with possibility: walkable cities, afforestation, bamboo, high-rises built of wood, marine permaculture, multistrata agroforestry, clean cookstoves, plant-rich diet, assisting women smallholders, regenerative agriculture, supporting girls’ ongoing education, smart glass, in-stream hydro, on and on.

D.B.: Is the Drawdown collaboration growing?

P.H.: Yes, coalitions are spontaneously arising all over the world. We are in direct relationships with several country and state governments on the policy level. There are Drawdown groups forming in NGOs and faith-based communities; impact investors are employing it; and teachers from fourth grade to graduate school are developing curriculum. Fifteen universities in the world are going to regionalize the model for their province, state and country. There are over 100 companies who are committing to Drawdown as their goal. There’s going to be an international Drawdown conference in 2019 organized by Penn State, the university that has contributed the most climate scientists to the IPCC. And Drawdown is going into 11 languages this year.

D.B.: Why do you think you’ve gotten such a strong response?

P.H.: I think people feel excluded by how the climate establishment has been communicating its message. The science is extraordinary, but science communication has been unintentionally inept. It’s been remote, fear-based and conceptual. Ninety-eight percent of all climate communication is about the probability of what’s going to go wrong and when. Those probabilities are based on impeccable science, for which we have profound respect, but constant repetition of a problem does not solve the problem. It shuts people down. With Drawdown, we don’t blame, shame or demonize. We don’t use fear as a motivating theme. We explore possibility because virtually all human beings move toward the possibility of a better life.