A Comprehensive Plan to Reverse Climate Change: Project Drawdown

Kevin Bayuk and Eric Toensmeier
Tuesday, 9th October 2018

An introduction to project Drawdown, which is proving through worldwide projects, that climate change can be halted and reversed. These are positive solutions the world can be adopting to prevent a global temperature rise (which we now need to keep under 1.5 degrees Celsius).

Paul Hawken, author of Natural Capitalism and Blessed Unrest, is an environmentalist, entrepreneur, author and activist who has dedicated his life to environmental sustainability and changing the relationship between business and the environment. In 2013, he began assembling an international team of scientists and policy makers and asked them to find out what are the most substantive solutions to reverse climate change and founded Project Drawdown. Maddy Harland asked Kevin Bayuk, Drawdown’s Senior Financial Fellow, and Eric Toensmeier, Senior Fellow for the Land and Food solutions, to explain how the project was structured and some of the early outcomes of a body of research that can literally change the world.

How the Drawdown Project came into Being

For over a decade Paul Hawken had been asking experts in the climate and environmental science field what is needed to reverse global warming and time again he was told that no one had yet rigorously indexed the solutions we know of and their potential beneficial impact. In 2013, Paul and Amanda Joy Ravenhill were teaching a class together about climate change when a series of dire reports and articles came out in popular literature that inspired them to develop a project to map, measure and model the one hundred known most substantive solutions that could, if adopted to a plausible potential, create a pathway to a point where greenhouse gases peak and begin to decline on a year-by-year basis – a point of Drawdown. 

The task was not an insignificant research and math problem. Over the next few years Project Drawdown assembled a team of over seventy researchers from twenty two countries who are experts in the science, policy and finance of the various solutions being studied by reaching out to the global climate research community through universities, NGOs and a broad coalition of partners and advisors.* Forty percent are women and almost half have PhDs in their field.

Two broad classifications of solutions were mapped: those related to reduction and replacement technologies which mitigate emissions and those related to land use and agriculture which both mitigate emissions and biosequester carbon from the atmosphere. These were then broken down into five clusters: Buildings and Cities; Energy; Food; Land Use; Materials, Transport and Women and Girls. Chad Frischmann was hired as the Research Director. He, Amanda and Paul hired a team of five Senior Researchers to support, oversee and review the work of the seventy Research Fellows.

Eric’s Role

For each solution, a research fellow prepared a technical report including a literature review, and entered data into a model that calculated the mitigation, biosequestration and economic impacts from 2020-2050. My role (Eric) is Senior Fellow for the Land and Food solutions. With my colleague Mamta Mehra, Senior Fellow for Biosequestration Modeling, I provided guidance to the research fellows on agricultural and ecosystem management solutions. Mamta and I wrote the completed reports and developed models for a number of the solutions ourselves.

Mamta and I also worked on integration between the solutions. For example, we built a spreadsheet that very roughly models all grassland, forest, and cropland on the planet. It breaks each down by degradation status, soil quality, slope, rainfall, and thermal climate. For each of these agroecological zones we assigned practices that we knew were already in place. For example, we knew there were already 100 million hectares of multistrata agroforestry (such as shade coffee and cacao). So we allocated the current adoption of all of our solutions and were left with quite a bit of land to work with. We assigned priorities to each of these agroecological zones, and plugged in the new adoption of solutions. This is a way to avoid double counting. It’s also basically a permaculture design for the entire planet, which was very interesting to do.

Another spreadsheet we developed modeled global food supply and demand from 2020-2050. Demand was a function of other solutions: Population (family planning and educating girls), with plant-based diet (less meat and dairy in wealthy countries, not veganism for all) and reduced food waste. Supply was based on how many hectares of such-and-such a practice (like silvopasture or a System of Rice Intensifi-cation), and their yields. We determined that business-as-usual leads to the need for much land clearing for agriculture by 2050, but that by imple-menting our farming practices, and reducing demand, the world can be fed in 2050 with no additional land clearing. A number of other researchers have come up with similar results but it was cool to see.

These days Mamta and I, and the other Senior Fellows, are getting all of our data ready to go up on drawdown.org, as only the summarized results made it into the book.

Kevin’s Role

My primary role when I joined the project was to co-develop the methodology for modeling the financial costs and con-sequences of all the solutions included in the project. This involved developing an iterative set of master core modeling spread-sheets that could accommodate an incredibly diverse set of variables, analyze those variables, factor them against statistically calibrated adoption prognosti-cations and develop common comparable financial outcomes for each solution. In addition to making and refining the spreadsheets, true to the generalist nature of permaculture design, I reviewed dozens of models and reports from various sectors including clean cookstoves, refrigerant management, farmland irrigation and greenroofs.

I had primary accountability for developing the integration framework for the materials solutions, making a master spreadsheet to track generation and processing of global municipal solid waste through solutions such as bioplastics, composting, industrial and household recycling, recycled paper, waste-to-energy and landfill methane recovery, to ensure no double counting and to measure and project rebound of adopting one solution on another. Similarly, I co-developed the integration methodology for the Buildings and Cities solutions.

Research Methodology

Drawdown has a set of research guidelines. It includes a literature review, entry of data into the model for meta-analysis, a guideline to always use conservative assumptions, and so on. The guidelines, as well as the technical reports and models, will eventually be up on the web. By the time this is published, our sector summaries and executive summaries for the solutions will be posted online. Of important note, the core 80 solutions of the 100 featured in the book are known solutions with substantial peer reviewed literature available on the atmospheric impact and, where available, the economic consequences of adoption of those solutions. 

Some of the key outcomes

It was pretty exciting to see that silvopasture was the most powerful agricultural solution. In fact all of our tree-based solutions (tree intercropping, silvopasture, multistrata agroforestry and tropical tree staples) had a powerful impact, though they are rarely given much due in climate mitigation papers. They are usually aggregated into an undifferentiated ‘agroforestry’ if discussed at all, which fails to bring out their unique potentials and limitations.

Not surprising to permaculture advocates and enthusiasts, Drawdown has contributed to the body of evidence that there are indeed solutions to reversing global warming and a pathway to peaking and then reducing the atmospheric concentration of greenhouse gases. Most of the solutions are in deep alignment with, and expressions of, permaculture ethics and principles, from placing voluntary limits to con-sump-tion and producing no waste, to integrating functions in land use and partnering with sources of renew-able energy. No one solution is adequate to the task, but a diverse mosaic of appropriate, site specific adoption of all the solutions can get humanity to the point of Drawdown.

Also not surprising to the permaculture community, but new to many of the people I have been sharing with and presenting Drawdown’s conclusions to, is the importance of three core themes with regard to mitigating climate change impacts: (1) empowering women and girls (2) embracing an indigenous perspective (3) appreciating the power of photosynthesis. Added together, educating girls and family planning would rank as the solution with the greatest mitigation impact. Indigenous land management, specifically, and more generally adopting practices of land use and agriculture that treat nature more as relatives than as resources, thematically underlie most of the significant land and conservation related solutions. While maybe self-evident to permaculture designers, land use and agriculture practices that optimize biomass and soil carbon storage are essential to reversing global warming.

What Outcomes Surprised Me

Drawdown ranks solutions by their mitigation impact. I was surprised to discover that refrigerant management had the highest impact of any solution. It wasn’t on my radar, but some refrigerant gases have 2,000 times the warming power of carbon dioxide. Carefully capturing those gases at end-of-life of refrigerators and air conditioners, and developing less dangerous replacements, is the single most powerful solution we modeled. Emissions reduction came to 89.7 billion metric tons of carbon dioxide equivalent between 2020-2050. By comparison, tropical reforestation has the equivalent impact of 61.2 billion metric tons of carbon dioxide equivalent (via biosequestration) in the same time period. We also found that the wind power solutions beat out solar in terms of total potential impact.

While all solutions matter and add up, I was surprised to see how little, compared to my expectations, transportation solutions contribute to mitigating emissions. Similarly, many of the solutions applicable to the built environment were less than expected, but some of this has to do with where we at Drawdown draw the boundaries of defining different solutions.

Drawdown’s Future Impacts

We’ve already been bringing the results to conferences including two big ones on carbon farming in the last month or two. The book is on the New York Times bestseller list and can be found in bookstores all over the world.

My personal aim is to use the book to leverage attention and resources for agroforestry and perennial crop systems. 

In some ways, the book is just the tip of the iceberg of data and research that will be released over time. Project Drawdown intends to continue to gather more data as it becomes available and refine, elaborate and regionalize the results to make them increasingly useful to policy makers, NGOs and the global finance community. While the book focuses on introducing the solutions in an accessible way and highlighting the direct financial costs and savings, and the impact on greenhouse gas emissions, the solutions also have significant ecosystemic effects and cascading benefits from their adoption. These are important to acknowledge and measure to influence policy and adoption. 

Drawdown overall has big plans, but they have not yet been announced. Stay tuned to our website!


Drawdown is edited by Paul Hawken and published by Penguin Books.

The official Drawdown site is: www.drawdown.org

Eric Toensmeier has studied useful perennial plants and their roles in agroforestry systems for over two decades. He is the author of The Carbon Farming Solution: A Global Toolkit of Perennial Crops and Regenerative Agricultural Practices for Climate Change Mitigation and Food Security released in February 2016, and the award-winning author of Paradise Lot and Perennial Vegetables, and the co-author of Edible Forest Gardens. Eric is an appointed lecturer at Yale University. He presents in English, Spanish and botanical Latin throughout the Americas and beyond. Eric has owned a seed company, managed an urban farm that leased parcels to Hispanic and refugee growers, and provided planning and business trainings to farmers. He is Drawdown’s Senior Fellow for the Land and Food solutions.

Kevin Bayuk works at the intersection of ecology and economy where permaculture design meets cooperative organizations intent on meeting human needs while enhancing the conditions conducive to all life. He facilitates classes, workshops, speaks and provides one-on-one mentoring as a founding partner of the Urban Permaculture Institute San Francisco. Having co-founded projects as diverse as enterprise communications management software to urban farming food security gardens, makes Kevin as fluent with information technology as with perennial polyculture agroforestry. He is Drawdown’s Senior Fellow in Financial Modeling.