Agricultural activities — crop and livestock production for food — contribute to emissions in a variety of ways. Half the emissions are due to soil management: tilling, application of synthetic fertilizers, drainage of organic-rich soil and irrigation practices. An additional +30% is due to ruminants generating methane and manure management.

One significant way that you can reduce the emissions due to this sector is to eat all the food stuffs that you purchase. While a lot of food is lost during harvest, storage and transportation, it is estimated that Americans throw away 30-40% of the food they buy- more than any other country. Some is due to misunderstanding the ‘use by’ labels, some to allowing food to rot instead of preparing and freezing it and some is due to in efficient use of leftovers. You impact this directly by increasing the percent you consume of the food you bring home.

Greenhouse gas emissions from businesses and homes arise primarily from fossil fuels burned for heat, the use of certain products that contain greenhouse gases, and the handling of waste.

Direct emissions are produced from residential and commercial activities in a variety of ways: 1) Combustion of natural gas and petroleum products for heating and cooking needs; 2) Organic waste sent to landfills emits; 3) Wastewater treatment; 4) Anaerobic digestion at biogas facilities emits; and 5) Fluorinated gases (mainly hydrofluorocarbons, or HFCs) used in air conditioning and refrigeration systems can be released during servicing or from leaking equipment. These have stayed flat since 1990.

Indirect emissions are produced by burning fossil fuel at a power plant to make electricity, which is then used in residential and commercial activities such as lighting and for appliances. These have decreased since 1990.

One significant way you can reduce direct emissions is to improve building energy efficiency with: better insulation; more energy-efficient heating, cooling, ventilation, and refrigeration systems; efficient fluorescent lighting; passive heating and lighting to take advantage of sunlight; and the purchase of energy-efficient appliances and electronics.

Greenhouse gas emissions from industry primarily come from burning fossil fuels for energy (2/3), as well as greenhouse gas emissions from certain chemical reactions necessary to produce goods from raw materials (1/3). Emissions are either directly generated at the site by operations or indirectly generated at other sites that supply the industrial site- for example at power plants generating electricity consumed in operations. As sites switch to alternative, sustainable energy sources, they have reduced their GHG emissions by nearly 1/5th since 1990.

Electricity production generates the second largest share of greenhouse gas emissions. Approximately 62 percent of our electricity comes from burning fossil fuels, mostly coal and natural gas. Emissions in the sector involve the generation, transmission, and distribution of electricity. Total GHG emissions from this sector have been trending downward since 2008 as gas and renewable-based generation increases its share.

You can directly impact this by:

Use electricity more efficiently- replace your heat pump or water heater with Energy Star products.

Use less electricity- replace incandescent light bulbs with LED, turn off lights when you will be out of a room for more than 10 min., set your thermostat lower in the winter and higher in the summer. Unplug electrical devices that are not in use- some consume power in standby mode.

Coming in at the #1, reducing the use of certain types of commonly-used refrigerants in air conditioners and refrigerators could remove 89.74 GT of CO2 equivalent at a cost of $0.90 trillion. Thanks to the 1987 Montreal Protocol on Substances That Deplete the Ozone Layer, certain destructive refrigerants were phased out within only a few years. However, the replacement refrigerant, HFCs (hydrofluorocarbons), while having no impact on the ozone layer are 1,000 – 9,000 times stronger as greenhouse gases than CO2. In 2016, over 170 countries negotiated a mandatory deal to start phasing out HFCs starting with high-income countries in 2019. It is interesting that the stimulus package just agreed to by Congress on 12/21/20 includes funding to eliminate the use of just these hydrofluorocarbons by 2035.

Coming in at #2, land-based wind turbines could reduce CO2 by 84.6GT annually. Together with the previous initiatives, this would be an annual reduction of 495GT, 13 times the total, current annual amount generated. The cost for this would be $1.23 trillion, but the savings would be $7.4 trillion for a 6x ROI. In the US, the wind energy potential of just 3 states- Kansas, North Dakota and Texas- would be sufficient to meet the total electricity demand of the whole US. Denmark now supplies more than 40% of electricity needs with wind power. Soon the cost per kilowatt-hour of wind will be lower than that for natural gas. As electrical storage and wide-area distribution networks improve, wind will be even more cost effective.

Coming in at #3, reducing food waste could reduce annual CO2 by 70.53GT. Together with the previous initiatives, this would reduce CO2 by 410GT/year. About 1/3 of food produced never gets eaten. Ranked with countries, the CO2 generated to create this lost food would be the 3rd largest emitter of greenhouse gases globally. The lost food drops out all along the food chain- lost in harvesting, lost in transit to distributors, lost in transit/storage from distributors to retailers, lost at retailers who throw away ‘ugly food’ and, finally, lost when the purchaser throws out spoiled and out-of-date food. This loss compounds the tragedy of hundreds of millions of people going hungry.

Coming in at #4, eating a plant-rich diet could reduce annual CO2 generated by 66.11GT. Together with the previous 5 initiatives, this would reduce CO2 by 339GT/year, about 10x our current rate of emission. It is conservatively estimated that raising livestock for food accounts for 15% of global GHG emitted each year. If cattle were their own nation, they would be the world’s third largest emitter. The WHO estimated that only 10-15% of one’s daily calories need come from protein and that a diet of primarily plants can meet that threshold. So eating lower on the food chain would serve a higher purpose. While the costs are too variable to be determined, it clearly would be much lower cost than raising and harvesting animals for food.

Tropical forests, located within 23.5 degrees north or south of the equator, once blanketed 12% of the world’s landmasses. Clearing for lumber, cropland and grazing has reduced this to just 5%. These forests can be returned to about 90% of their previous biomass size within a relatively short span- only 60 years. This takes CO2 out of the air, supports the water cycle, conserves soil, protects habitats and pollinators, provides food, medicine and fiber and gives people places to live. This could reduce annual CO2 generate by 61.23GT, but the cost and savings are too variable to be determined. Implementing this and all the previous actions would reduce annual CO2 generated by over 273GT annually, which is about 7.6x the annual CO2 generated.

Coming in at #6, Educating Girls is another non-technology driven approach. It could reduce annual CO2 generation by 59.6T. Educated girls have fewer children, realize higher wages and contribute greatly to economic growth. Their agricultural plots are more productive and their families better nourished. This “is the most powerful lever available for breaking the cycle of intergenerational poverty, while curbing emissions by curbing population growth.”

Coming in at #7, Family Planning could reduce CO2 by 59.6GT (about 1-1/2 times the annual amount created annually in 2016). Not surprisingly, the amount of CO2 generated is proportional to the number of people on earth… the more people, the more CO2 they produce. So, providing quality family planning, including access to contraception, would allow families to control the spacing and number of children they have. This option was not costed out- the authors say it is “inappropriate to monetize a human right”.

Coming in at #8, Solar Farming could reduce CO2 by 36.9GT (almost exactly the amount of total annual amount created in 2016). This is NOT small-scale rooftop installations of solar panels. Rather it is large-scale installation of sometimes millions of Photovoltaic (PV) panels that generate megawatts of electrical power. These utility-scale installations generate power equivalent to a nuclear power generation plant, but without the radioactive waste. Achieving this level of CO2 reduction would cost $80.6 billion, but would save $5,020 billion for about a 60x savings.

Coming in at #9, Silvopasture could lead to a 31.19 GT Total CO2-EQ reduction. A few words about the units here. GT stands for a gigaton or 1 billion tons. 36GT of CO2-EQ is the total amount of CO2 emitted from all sources in 2016. Now on to the interesting stuff. Silvopasture, the raising livestock in a mixed pasture and woodland, is finding increased acceptance for a number of reasons. Pasture with trees sequesters 5-10x the amount of carbon compared to treeless pasture. The livestock yield is higher than on treeless pasture and this combination leads to healthier soil that grows a better forage. The trees themselves can produce additional financial benefits from products such as nuts, fruits or maple syrup. If expanded from the current 351 million acres of land globally to 554 million by 2050 (this would be less than 20% of the land available for conversion), the estimated cost is $41.59 billion, with a net savings of $699.37 billion for almost a 17x savings.

A full description of the methodology, an update to their findings and many other resources can be found at www.drawdown.org. The intent of these approaches is NOT to just avoid further increases, but to reduce the amount of human-generated greenhouse gases in the environment over the next 30 years between 2020 and 2050. Coming in at #10, Rooftop Solar could reduce greenhouse gases by 24.6 gigatons over this period. This is small-scale installation of solar panels on the roofs of buildings rather than in large-scale solar farms. Their models assume rooftop solar can grow from 0.4% of electricity generation globally to 7% by 2050. The cost to do this is estimated at $0.45 trillion, but the net savings is almost 10x this at $3.46 trillion.

In the book Drawdown: The most comprehensive plan ever proposed to reverse global warming, Paul Hawken, editor (2017), the authors analyze a wide variety of approaches to reverse global warming. The book lists their top 80, of which the top 10 are: 1. Refrigerant Management, 2. Wind Turbines (Onshore), 3. Reduced Food Waste, 4. Plant-Rich Diet, 5. Tropical Forests, 6. Educating Girls, 7. Family Planning, 8. Solar Farms, 9. Silvopasture, 10. Rooftop Solar.

Surprised? Curious? Over the next months, I’ll review each in a weekly tip. Note that most of these are big societal/commercial scale items, but others like items 3, 4 and 10 are small, consumer scale.