Solar farms rank #8 on Drawdown’s list of climate solutions, with the potential to eliminate 36.9 gigatons of carbon dioxide and produce net savings of US$5 trillion by 2050. On top of that the implementation costs of solar farms could deliver $81 billion in additional savings compared to fossil plants.

Educating girls ranks #6 on Drawdown’s list of climate solutions. By 2050, if universal education is achieved in low- and lower-middle-income countries, educating girls can eliminate 59.6 gigatons of carbon dioxide, with costs and savings that are both incalculable.

Restoration of Tropical Forests places #5 on the Drawdown list of climate solutions, with potential to cut atmospheric carbon dioxide by 61.23 gigatons by 2050.

Multistrata Agroforestry places #28 on the Drawdown list of climate solutions, with the potential to cut atmospheric carbon dioxide by 9.28 gigatons by 2050, with an up-front cost of $26.8 billion but net savings of $709.8 billion.

Industrial recycling ranks #56 on Drawdown’s list of climate solutions, with potential to keep 2.8 gigatons of carbon dioxide out of the atmosphere over a 30-year period. Using commercial waste to produce new products also addresses another persistent problem: the scarcity that occurs when industries use virgin resources faster than the Earth can reproduce them.

Heat Pumps show up as #42 in Drawdown’s list of climate solutions, with experts predicting a 5.2-gigaton drop in carbon dioxide emissions through 2050 if the solution is adopted by 45% of the market. Replacing air conditioners and gas furnaces with high-efficiency heat pumps has a net implementation cost of roughly US$119 billion, but would produce estimated savings of nearly $1.55 trillion.

The Artificial Leaf shows up on Drawdown’s list of Coming Attractions—a category of climate solutions that weren’t yet ready for widespread adoption when the book appeared, but seemed likely to contribute to a decarbonization target by mid-century. The technology would use a process based on natural photosynthesis to produce energy.

Waste-to-Energy ranks #68 in Drawdown’s list of climate solutions, with the potential to cut carbon emissions by 1.1. gigatons over a 30-year period.

Net Zero Buildings place #79 on Drawdown’s list of climate solutions, capable of sequestering 7.1 gigatons of carbon by 2050 if only 9.7% of new buildings hit the standard. Net zero designs, which enable a structure to generate as much energy as it consumes over the course of a year, integrate multiple energy solutions, so Drawdown calculates their impact as a single system.

Drawdown lists Repopulating the Mammoth Steppe as a Coming Attraction—one of a collection of climate solutions that are not yet ready for widespread adoption, but should be able to contribute to global decarbonization by 2050. The solution hinges on reintroducing herds of migratory herbivores to the Arctic regions of the world, where vast stores of carbon are locked in the permafrost.

A change in rice cultivation methods known as a System of Rice Intensification (SRI) lands at #53 on Drawdown’s list of climate solutions. Wider adoption of the technique could cut carbon dioxide emissions by 3.13 gigatons and save US$678 million by 2050.

Temperate forest restoration places #12 on Drawdown’s list of climate solutions. The research team estimates that by 2050, temperate forests will naturally grow by 235 million acres and could sequester 22.61 gigatons of carbon dioxide emissions.

High-speed rail places #66 on Drawdown’s list of climate solutions. A global network of trains that travel at speeds of at least 220 kilometres per hour would cost close to US$1.3 trillion to install, but that budget would be almost entirely recouped over the lifetime of the infrastructure.

Ocean farming is featured as one of Drawdown’s “coming attractions”—climate solutions that weren’t ready for prime time when the book appeared, but could make a difference by mid-century. 

Clean cookstoves are ranked #21 on Drawdown’s list of climate solutions, with the ability to reduce carbon dioxide emissions by 15.81 gigatons by 2050. Nearly three billion households—40% of the people on earth—prepare meals over open fires fueled by wood, coal, animal dung, or agricultural refuse. Drawdown estimates that replacing these traditional methods with newer, cleaner technologies would cost US$72.16 billion, roughly $41 per stove, for a net saving of $166 billion in total operational costs over the 30-year period.

Refrigerant management places #1 on the Drawdown list of climate solutions, with potential to prevent the equivalent of 89.7 gigatons of carbon dioxide from entering the atmosphere by 2050.

rge methane digesters rank #30 on Drawdown’s list of climate solutions, with potential to reduce greenhouse gas emissions by 8.4 gigatons by 2050. They operate at less cost than the conventional coal and natural gas power plants they replace, and would produce an estimated US$148.83 billion in savings over 30 years.

Generating electricity with onshore wind turbines ranks #2 on Drawdown’s list of climate solutions. In 2017, onshore wind generated approximately 4% of the world’s electricity. Boosting that figure to 21.6% would cut CO2 emissions by 84.6 gigatons, as wind energy gradually replaces plants powered by coal, natural gas, and oil.

Reduced food waste places #3 on the Drawdown list of climate solutions. Reducing global food waste by 50% could decrease carbon emissions by a total of 70.53 gigatons by 2050, including emissions that would be cut by preventing deforestation for farmland.

Microgrids come in at #78 on Drawdown’s list of climate solutions. Defined as locally-managed electricity generation systems, microgrids can be powered by renewable resources like micro-wind, solar power, in-stream hydro, and biomass energy—whatever resources are available. Drawdown doesn’t quantify the carbon reduction value of microgrids independently, but includes their positive impact in its calculations for each energy source.

Managed grazing ranks #19 on the Drawdown climate solutions list. Altering conventional grazing practices would sequester 16.3 gigatons of carbon dioxide by 2050, making it the second-most effective land use carbon sequestration solution. Extending the approach to 1.1 billion acres, up from the 195 million acres where they are now in use, would cost US$50.48 billion to implement and deliver savings of $735 billion by 2050.

Improving aircraft fuel efficiency ranks #43 on the Drawdown list of climate solutions, with the potential to reduce atmospheric carbon dioxide by 5.05 gigatons by 2050. The shift would cost US$662.4 billion, but produce net savings of $3.19 trillion.

Living buildings is one of the 20 carbon reduction options that Drawdown lists as Coming Attractions—strategies that weren’t ready for prime time when the book was published, but looked like promising approaches through mid-century.

Drawdown lists the Hyperloop as a Coming Attraction—a climate solution in development that is not yet ready for prime time, but might be by mid-century.

Afforestation—cultivating timber plantations on previously depleted land—comes in at #15 on Drawdown’s list of climate solutions. By sequestering carbon in timber, soil, and biomass, newly-planted forests can reduce atmospheric carbon dioxide by 18.06 gigatons, Drawdown calculates. And from an initial implementation cost of US$29.44 billion, a net operational savings of $392.33 billion is projected to grow.

Replacing soil-depleting annual food species with perennial crops is one of the 20 carbon reduction options that Drawdown lists as Coming Attractions—strategies that weren’t ready for prime time when the book was published, but looked like promising approaches through mid-century.

Household recycling ranks #55 on Drawdown’s list of climate solutions. It could eliminate 2.77 gigatons of carbon dioxide emissions at a net cost of US$366.9 billion, while producing net savings of $71.1 billion.

Substantially replacing cotton with industrial hemp is one of the 20 carbon reduction options that Drawdown lists as Coming Attractions—strategies that weren’t ready for prime time when the book was published, but looked like promising approaches through mid-century.

Building with wood is making a comeback, and is included in Drawdown’s list of “coming attractions” as a decarbonization option that hasn’t yet hit the mainstream, but could be a part of a wider set of post-carbon solutions by 2050.

Intensive silvopasture is one of the 20 carbon reduction options that Drawdown lists as Coming Attractions—strategies that weren’t ready for prime time when the book was published, but looked like promising approaches through mid-century.

Solid state wave energy is one of 20 carbon reduction options in Drawdown’s list of “coming attractions” that hold major future promise, but aren’t quite ready for prime time. The technology has incredible potential, but faces barriers to becoming a current, mainstream solution.

A shift to smart highways is one of the 20 carbon reduction options that Drawdown lists as Coming Attractions—strategies that weren’t ready for prime time when the book was published, but looked like promising approaches through mid-century.

Smart grid development is a low-carbon solution that Drawdown lists as a “coming attraction” that can help utilities accommodate the rise of renewable energy. It could also eliminate 0.7 to 2.1 gigatons of carbon dioxide by 2050.

Regenerative Agriculture places #11 on the Drawdown list of climate solutions, with the potential to cut atmospheric carbon dioxide by 23.15 gigatons. It carries an up-front cost of US$57.2 billion, but promises savings of $1.93 trillion, by 2050.

Autonomous vehicles are included in Drawdown’s list of “coming attractions” as an up-and-coming climate solution that hasn’t yet become the norm.

Nutrient management ranks #65 on Drawdown’s list of climate solutions, with potential to eliminate 1.81 gigatons of carbon dioxide and save a total of US$102.3 billion by 2050.

Cogeneration ranks #50 on Drawdown’s list of climate solutions, with the potential to eliminate 3.97 gigatons of carbon dioxide at a net cost of US$279.3 billion, while producing savings of $567 billion.

Recycled paper ranks #70 on Drawdown’s list of climate solutions. By 2050, recycled paper could eliminate 900,000 megatons of carbon dioxide emissions at an initial cost of US$573.5 billion, with eventual savings that are too indefinite to calculate.

Grid flexibility places #77 on Drawdown’s list of climate solutions as an essential tool for making 80% renewable generation “a global reality” by 2050. Its costs and savings are impossible to calculate, as they will be embedded in local renewable energy projects around the globe.

Critical to enabling a wholesale shift to variable sources of renewable power like solar and wind will be Utility-Scale Energy Storage which, alongside grid flexibility, places #77 on Drawdown’s list of climate solutions.

Increased cultivation of perennial bioenergy crops ranks #51 on Drawdown’s list of climate solutions, with the potential to reduce atmospheric carbon dioxide by 3.33 gigatons by 2050 at a net cost of US$77.9 billion, but net savings of $542 billion.

Electrified rail places #74 on Drawdown’s list of climate solutions, with the potential to reduce atmospheric carbon dioxide by 500 megatons by 2050. While expanding rail lines around the world from 166,000 to 621,000 miles (267,150 to about one million kilometres) would cost US$809 billion, 30 years of use would see $314 billion saved, with a further $770 billion in savings over the life of the infrastructure.

In-stream hydro ranks #48 on Drawdown’s list of climate solutions, with the potential to reduce atmospheric carbon dioxide by 4.0 gigatons by 2050, at a net cost of US$202.5 billion but with net savings of $568.4 billion.

Normalizing and intensifying the composting of food waste ranks #60 on Drawdown’s list of climate solutions, with the potential to reduce atmospheric carbon by 2.28 gigatons by 2050.

Ramping up production of bioplastics ranks #47 on Drawdown’s list of climate solutions, with potential to reduce atmospheric carbon dioxide by 4.3 gigatons by 2050. First costs to capture 50% of the plastics market within 30 years would peak at US$19.2 billion.

Protection of Coastal Wetlands ranks #52 on Drawdown’s list of climate solutions. The strategy could reduce atmospheric carbon dioxide by 3.3 gigatons by 2050, as long as 75 million acres of these vital ecosystems (out of a total of 121 million world-wide) can be secured within the next 30 years.

Accelerating the production of biochar ranks #72 on Drawdown’s list of climate solutions, with the potential to reduce atmospheric carbon by 810 megatons by 2050.

Solar water heating ranks #41 on Drawdown’s list of climate solutions. It could eliminate 6.08 gigatons of carbon dioxide by 2050 at a net cost of US$3 billion, resulting in net savings of $773.7 million.

Increasing transport ship efficiency places #32 on Drawdown’s list of climate solutions. Efficiency gains of 50% across the sector, at a net cost of US$915.9 billion, could prevent 7.9 gigatons of CO2 emissions by 2050, while saving the international marine industry US$1 trillion in fuel costs over the life of the vessels.

Bike infrastructure ranks #59 on Drawdown’s list of climate solutions. Better and more widespread bike infrastructure would eliminate 2.31 gigatons of carbon dioxide and produce net savings of US$400.5 billion, with further lifetime savings of $2.1 trillion.

Micro wind places #76 on Drawdown’s list of climate solutions. If its share of global electricity generation increases to 1%, it could eliminate 0.2 gigatons of carbon dioxide at a cost of $US36.1 billion, against savings of $19.9 billion.

Ridesharing ranks #75 on the Drawdown list of climate solutions. It could cut atmospheric carbon dioxide by 0.32 gigatons at no cost, resulting in net savings of US$185.6 billion. That calculation is exclusive to commuters in Canada and the United States, and assumes ridesharing will rise to 15% of car commuters by 2050.

Alternative cement places #36 on Drawdown’s list of climate solutions, with the potential to avoid 6.69 gigatons of atmospheric carbon dioxide by 2050. The shift would save US$174 billion, because such alternatives ultimately last longer.

Green roofs rank #73 on Drawdown’s list of climate solutions. By the year 2050, an increase in green and cool roofs could save 0.77 gigatons of carbon at a net cost of US$1.39 trillion, while producing $988.5 billion in savings.

Electric bikes place #69 on Drawdown’s list of climate solutions. They can eliminate 0.96 gigatons of carbon dioxide emissions by 2050 at a cost of $US106.8 billion, with net savings of $226.1 billion.

Smart glass ranks #61 on Drawdown’s list of climate solutions. By 2050, smart glass can eliminate 2.19 gigatons of carbon dioxide at a net cost of $US74.2 billion, and would result in $321.5 billion in savings.

Insulation places #31 on the Drawdown list of climate solutions, with the potential to cut atmospheric carbon dioxide by 8.27 gigatons by 2050. The option carries an upfront cost of US$3.66 trillion, $2.5 trillion of which would be recouped within 30 years.

Water saving in the home places #46 on Drawdown’s list of climate solutions. It can eliminate 4.61 gigatons of carbon dioxide emissions by 2050 at a net cost of $US72.44 billion, producing net savings of $1.8 trillion, based solely on energy savings from more efficient use of hot water.

Burning biomass to produce electricity places #34 on Drawdown’s list of climate solutions. It could avoid 7.5 gigatons of atmospheric carbon dioxide by 2050 at a net cost of US$402.3 billion, with net savings of $519.4 billion.

Silvopasture ranks #9 on Drawdown’s list of climate solutions. By 2050, the technique could eliminate 31.9 gigatons of carbon dioxide at a net cost of US$41.6 billion, leading to $699.4 billion in net savings.

Pasture Cropping, where annual crops are cyclically planted in perennial pastures, is one of the 20 carbon reduction options that Drawdown lists as Coming Attractions—strategies that weren’t ready for prime time when the book was published, but looked like promising approaches through mid-century.

Forest protection places #38 on Drawdown’s list of climate solutions, with the potential to avoid 6.2 gigatons of carbon dioxide emissions by 2050 and sequester an astonishing 896.29 gigatons.

Microbial farming, which involves reseeding exhausted farmland with the diverse microbiome upon which productive soil depends, is one of the 20 carbon reduction options that Drawdown lists as Coming Attractions—strategies that weren’t ready for prime time when the book was published, but looked like promising approaches through mid-century.

Marine permaculture technology that seeds the world’s oceans with kelp forests while pumping up colder, nutrient-rich waters from the ocean depths is one of the 20 carbon reduction options that Drawdown lists as Coming Attractions—strategies that weren’t ready for prime time when the book was published, but looked like promising approaches through mid-century.

Expanding use of mass transit ranks #37 on Drawdown’s list of climate solutions, with the potential to eliminate 6.57 gigatons of carbon dioxide and produce US$2.38 trillion in savings. The cost, according to Drawdown, is too variable to be determined.

Building automation ranks #45 on Drawdown’s list of climate solutions. It could eliminate up to 4.62 gigatons of carbon dioxide by 2050 at a cost of US$68.1 billion, eventually saving building owners around $880.6 billion.

Concentrated Solar Power (CSP) places #25 on Drawdown’s list of climate solutions. Scaling up CSP to 4.3% of global electricity production by 2050 would avoid 10.9 gigatons of carbon dioxide. While implementation costs of CSP are high, at US$1.3 trillion, net savings by 2050 could total $414 billion, with lifetime savings of $1.2 trillion.

More efficient water distribution places #71 on the Drawdown list of climate solutions. It could cut atmospheric carbon dioxide by 870 megatons by 2050 at a cost of US$137.4 billion, producing net savings of $903.1 billion.

Tropical staple trees rank #14 on Drawdown’s list of climate solutions. This option could eliminate 20.19 gigatons of atmospheric carbon dioxide at a cost of $US120.1 billion, producing savings of $627 billion.

Farmland Restoration places #23 on Drawdown’s list of climate solutions. Restoring 424 million acres of abandoned farmland to rich agricultural life by 2050 would, after a total investment of $72 billion, sequester 14.08 gigatons of carbon dioxide while providing a financial return of $1.3 trillion—and an additional 9.5 billion tonnes of food.

Intensive silvopasture is one of the 20 carbon reduction options that Drawdown lists as Coming Attractions—strategies that weren’t ready for prime time when the book was published, but looked like promising approaches through mid-century.

Increasing fuel efficiency in the global freight trucking industry places #40 on Drawdown’s list of climate solutions. It could reduce atmospheric emissions of carbon dioxide by 6.2 gigatons by 2050, at a net cost of US$543.5 billion, but $2.78 trillion in net savings.

Geothermal places #18 on the Drawdown list of climate solutions. If it could increase its share of global electricity generation from 0.66 to 4.9% by 2050, geothermal would prevent 16.6 gigatons of CO2 emissions, at a net cost of $US155.5 billion but net savings of $US 1.02 trillion.

Producing energy from landfill methane ranks #58 on Drawdown’s list of climate solutions, with the potential to reduce atmospheric emissions by the equivalent of 2.5 gigatons of carbon dioxide by 2050, at a net cost of -US$1.8 billion and net savings of $67.6 billion.

Telepresence ranks #63 on Drawdown’s list of climate solutions. It could cut atmospheric carbon dioxide by 1.99 gigatons by 2050 at a cost of $US127.7 billion, creating a net savings of $1.31 trillion.

Indigenous Peoples’ Land Management ranks #39 on Drawdown’s list of climate solutions. It can reduce atmospheric carbon dioxide by 6.19 gigatons and sequester 849.37 gigatons of carbon by 2050.

Wave and tidal power ranks #29 on Drawdown’s list of climate solutions. By 2050, this alternative energy source could eliminate 9.2 gigatons of atmospheric carbon dioxide at a cost of US$412 billion. Drawdown calculates that the installations would produce a net financial loss of $1 trillion over three decades, but the investment would result in substantial emission reductions over that time.

Increased cultivation and use of Bamboo places #35 on the Drawdown list of climate solutions, with potential to cut atmospheric carbon dioxide by 7.22 gigatons of carbon dioxide. It would cost US$23.8 billion, but savings of $264.8 billion by 2050.

Family Planning places #7 in Drawdown’s list of climate solutions. It could reduce atmospheric carbon dioxide by 59.6 gigatons by 2050—and without it, a billion more people could be added to the world’s population.

District heating ranks #27 on Drawdown’s list of climate solutions. By 2050, the technique could eliminate 9.38 gigatons of carbon dioxide at a net cost of US$457.1 billion, and produce $3.54 trillion in savings.

Smart thermostats place #57 on the Drawdown list of climate solutions. By 2050, this technology could reduce atmospheric carbon dioxide by 2.6 gigatons at a cost of US$74.2 billion and produce net savings of $640.1 billion in utility bills.

Walkable Cities place #54 on the Drawdown list of climate solutions. The strategy could cut atmospheric carbon dioxide by 2.92 gigatons by 2050 and produce an astounding US$3.28 trillion in net operational savings, though the corresponding costs are too variable to measure.

A plant-rich diet places #4 on the Drawdown list of climate solutions. While data vary too widely for a comprehensive global accounting, Drawdown sees a global shift away from the “meat-centric, highly processed, often excessive Western diet” cutting atmospheric carbon dioxide by 66.11 gigatons by 2050, saving trillions of dollars in health care costs, and boosting global GDP by as much as 13%.

Conservation Agriculture ranks #16 on the Drawdown list of climate solutions. It would keep 17.35 gigatons of CO2 from entering the atmosphere by 2050 at a net implementation cost of US$37.5 billion, and bring US$2.12 trillion net savings.

Supporting women smallholders ranks #62 on Drawdown’s list of climate solutions. It would reduce 2.06 gigatons of atmospheric carbon dioxide by 2050 and produce $US87.6 billion in net savings.

Tree Intercropping places #17 on Drawdown’s list of climate solutions. Intercropping on 571 million acres globally by 2050 would sequester 17.2 gigatons of carbon dioxide and, after a total investment of US$147 billion, save $22.1 billion over the 30-year span.

Peatlands restoration is ranked #13 on Drawdown’s list of climate solutions. It can avoid 21.57 gigatons of carbon dioxide emissions by 2050. While data are too variable to permit a global accounting of costs, those hundreds of millions of acres of protected lands will permanently secure 1,200 gigatons of carbon dioxide from being released into the atmosphere.

Producing energy from landfill methane ranks #58 on Drawdown’s list of climate solutions, with the potential to reduce atmospheric emissions by the equivalent of 2.5 gigatons of carbon dioxide by 2050, at a net cost of -US$1.8 billion and net savings of $67.6 billion.

Forest protection places #38 on Drawdown’s list of climate solutions, with the potential to avoid 6.2 gigatons of carbon dioxide emissions by 2050 and sequester an astonishing 896.29 gigatons.

Concentrated Solar Power (CSP) places #25 on Drawdown’s list of climate solutions. Scaling up CSP to 4.3% of global electricity production by 2050 would avoid 10.9 gigatons of carbon dioxide. While implementation costs of CSP are high, at US$1.3 trillion, net savings by 2050 could total $414 billion, with lifetime savings of $1.2 trillion.

Indigenous Peoples’ Land Management ranks #39 on Drawdown’s list of climate solutions. It can reduce atmospheric carbon dioxide by 6.19 gigatons and sequester 849.37 gigatons of carbon by 2050.

Building automation ranks #45 on Drawdown’s list of climate solutions. It could eliminate up to 4.62 gigatons of carbon dioxide by 2050 at a cost of US$68.1 billion, eventually saving building owners around $880.6 billion.

District heating ranks #27 on Drawdown’s list of climate solutions. By 2050, the technique could eliminate 9.38 gigatons of carbon dioxide at a net cost of US$457.1 billion, and produce $3.54 trillion in savings.

Geothermal places #18 on the Drawdown list of climate solutions. If it could increase its share of global electricity generation from 0.66 to 4.9% by 2050, geothermal would prevent 16.6 gigatons of CO2 emissions, at a net cost of $US155.5 billion but net savings of $US 1.02 trillion.

Conservation Agriculture ranks #16 on the Drawdown list of climate solutions. It would keep 17.35 gigatons of CO2 from entering the atmosphere by 2050 at a net implementation cost of US$37.5 billion, and bring US$2.12 trillion net savings.

Tropical staple trees rank #14 on Drawdown’s list of climate solutions. This option could eliminate 20.19 gigatons of atmospheric carbon dioxide at a cost of $US120.1 billion, producing savings of $627 billion.

Wave and tidal power ranks #29 on Drawdown’s list of climate solutions. By 2050, this alternative energy source could eliminate 9.2 gigatons of atmospheric carbon dioxide at a cost of US$412 billion. Drawdown calculates that the installations would produce a net financial loss of $1 trillion over three decades, but the investment would result in substantial emission reductions over that time.

Tree Intercropping places #17 on Drawdown’s list of climate solutions. Intercropping on 571 million acres globally by 2050 would sequester 17.2 gigatons of carbon dioxide and, after a total investment of US$147 billion, save $22.1 billion over the 30-year span.

Temperate forest restoration places #12 on Drawdown’s list of climate solutions. The research team estimates that by 2050, temperate forests will naturally grow by 235 million acres and could sequester 22.61 gigatons of carbon dioxide emissions.

Supporting women smallholders ranks #62 on Drawdown’s list of climate solutions. It would reduce 2.06 gigatons of atmospheric carbon dioxide by 2050 and produce $US87.6 billion in net savings.

More efficient water distribution places #71 on the Drawdown list of climate solutions. It could cut atmospheric carbon dioxide by 870 megatons by 2050 at a cost of US$137.4 billion, producing net savings of $903.1 billion.

A plant-rich diet places #4 on the Drawdown list of climate solutions. While data vary too widely for a comprehensive global accounting, Drawdown sees a global shift away from the “meat-centric, highly processed, often excessive Western diet” cutting atmospheric carbon dioxide by 66.11 gigatons by 2050, saving trillions of dollars in health care costs, and boosting global GDP by as much as 13%.

Telepresence ranks #63 on Drawdown’s list of climate solutions. It could cut atmospheric carbon dioxide by 1.99 gigatons by 2050 at a cost of $US127.7 billion, creating a net savings of $1.31 trillion.

Increased cultivation and use of Bamboo places #35 on the Drawdown list of climate solutions, with potential to cut atmospheric carbon dioxide by 7.22 gigatons of carbon dioxide. It would cost US$23.8 billion, but savings of $264.8 billion by 2050.

Restoration of Tropical Forests places #5 on the Drawdown list of climate solutions, with potential to cut atmospheric carbon dioxide by 61.23 gigatons by 2050.

Walkable Cities place #54 on the Drawdown list of climate solutions. The strategy could cut atmospheric carbon dioxide by 2.92 gigatons by 2050 and produce an astounding US$3.28 trillion in net operational savings, though the corresponding costs are too variable to measure.

Family Planning places #7 in Drawdown’s list of climate solutions. It could reduce atmospheric carbon dioxide by 59.6 gigatons by 2050—and without it, a billion more people could be added to the world’s population.

Reduced food waste places #3 on the Drawdown list of climate solutions. Reducing global food waste by 50% could decrease carbon emissions by a total of 70.53 gigatons by 2050, including emissions that would be cut by preventing deforestation for farmland.