Each of the 100 solutions falls under one or more categories of the three things we can do about global warming: stop the release of greenhouse gases into the atmosphere; change to renewable energy low in carbon emissions; and sequestration, bringing carbon back to the earth through photosynthesis. Of the three, sequestration is probably the least understood but most important when it comes to achieving the goal stated in the project’s name: drawdown. Climate drawdown means that we not only limit our carbon emissions, but also begin to lower greenhouse gas levels in the atmosphere.

“All of the solutions we list and model already exist, are well understood and are scaling,” Hawken says. “And virtually all of them are getting less expensive and more practical every year.” What emerges from this list of solutions is some clarity about the path forward on global warming, which, in a media landscape that tends to exacerbate fear and despair around this topic, is a real reason for feeling optimistic. The other reason is that this is the first time we have had a complete list of the top solutions to global warming since climate change came to the fore 40 years ago. Really, the first time.

Sam Mowe

What does drawdown mean? It means different things in different contexts, but in the context of Project Drawdown it means that point in time when greenhouse gases peak and go down on a year-to-year basis. We named the project and book Drawdown in order to name the goal. If we don’t name the goal, it’s unlikely that we’ll hit it as a civilization. When you name the goal, it opens up possibilities for solutions in terms of ideas, imagination, creativity, and inclusion.

Most of the time when we talk about climate solutions, we talk about cutting back on or eliminating our carbon emissions in order to slow down global warming and minimize its negative impacts. Why is climate drawdown the goal?Slowing down is fine and good, but it’s not the goal. The level of carbon dioxide in the atmosphere is higher than it’s been since the Miocene period. It’s never been this high since humans existed, which means we have no idea what will happen at this level. So the idea of stabilization at 450 or 400 parts per million is not sensible.

The last time greenhouse gases were as high as 290 parts per million was the Eemian period, about 125,000 years ago, when there were alligators and hippopotami lounging in the Thames River Delta, giraffes and lions romping in Germany, and alligators in Alaska. That’s 290 ppm. We’re at 402 ppm and climbing. This is why drawdown is the goal. If you’re heading toward a cliff and you slow down, you’re still going to go over the cliff. In a sense, our goals around climate change have been like Thelma & Louise in slow motion.

Drawdown offers 100 climate solutions—80 of which are already well established. The remaining 20 are in various stages of development. What are the next steps to achieve drawdown? The question we asked ourselves to begin the project was: if existing climate solutions continue to scale in a rigorous but reasonable way, could we achieve drawdown in 30 years? Our first job was to identify the most substantive solutions. We went through a few hundred of them. As we started to do preliminary models, some of them dropped out and others were added. Eventually we winnowed the list down to what’s in the book and on the website.

Often when people talk about climate change and global warming, they focus on ideas or solutions that have never been done before, such as proposals to make hydrogen from coal with carbon-capture systems. Dr. James Hansen recommends building 115 nuclear power plants every year for the next 30 years, which is nearly physically impossible, not to mention that there are many sound reasons not to do it. You have people proposing solutions that are based on beliefs, not on math. We did the math. It hadn’t been done before on a full and comprehensive list of salient solutions. In doing so we discovered what the largest and most impactful existing solutions were, and we ranked them.

Can you give us a specific example of a project in Drawdown and tell us how it works? Reducing food waste is a very important solution. The world wastes about 30% of the food that’s produced. The United States is somewhere between 40–50%. Food waste has a big carbon backpack on it. It takes a lot of energy to create that food in terms of agriculture, emissions of carbon due to tillage of the soil, pesticide and herbicide use, trucking, processing, packaging, delivery to the store, taking it home, and throwing it away.

Reducing food waste allows us to produce less food, changing the impact we have on the land. For example, in the Amazon, where forests are still being burned in order to create land for soybeans, which is for cattle, which is for beef, which is for hamburgers. Anytime you reduce the amount of food you use, you’re going to reduce impact upon the land, especially if it is meat.

What has been overlooked in the climate solution world is the capacity of agricultural, grazing, and integrated forest practices to not only reduce carbon emissions but also bring carbon back home. Drawdown can be achieved only through photosynthesis at this point, whether it is plants on land or phytoplankton at sea. In the book, we model 25 land-use solutions that sequester carbon while simultaneously increasing productivity, plant and animal health, water infiltration, and, on the other side, reducing erosion, flood damage, and loss of biodiversity.

What we need is to be fearless, not hopeful, because to be hopeful means that our actions are based on fear. No action based on fear has a good outcome.”