Carbon 101 and Biofuels
Here are some basics you need to understand about combatting climate change. You don’t need a PhD or to be of any particular political persuasion to comprehend this. These are the fundamentals to master if you want to engage in debate or effectively find solutions to global warming.
The reason we have a problem with greenhouse gases (GHGs) is because we burn a lot of fossil fuels. Coal, petroleum, and natural gas all contain carbon that was permanently locked away in the Earth’s crust until we learned how to extract it and use it for energy. Our rapid exploitation of fossil fuels is adding carbon to the atmosphere faster than natural systems can handle.
Everyone knows that trees (and other plant life) absorb carbon from the atmosphere. It’s important to remember that plants also return their carbon to the atmosphere when they die and decompose. If a forest burns; or if a plant is eaten by an animal; or if it is decomposed by microorganisms, almost all of the carbon in that plant returns to the atmosphere. Carbon can be stored in some soils, but there is also a limit to how much carbon can be sequestered in soils before it returns to the atmosphere through oxidation or biological action. All of the plants on Earth are busy absorbing and emitting their own carbon. Asking the forests to take on the burden of absorbing our additional fossil fuel pollution is not a solution.
Forests and natural ecosystems everywhere should be protected to maintain biodiversity and the role they play in the hydrologic and other natural cycles. However, what happens to the forests and plant communities is not the cause, nor is it the solution of our GHG crisis. The scale at which we can stash away a bit of extra carbon by planting trees is simply too small to put a dent in our fossil fuel habit. Between 2004 and 2011, we added 19 million acres of forest to the global landscape.i In the US, we added enough trees to absorb an additional 762.4 MMT of CO2 equivalent in 2015. On the other hand, we (the US in 2015) emitted over 5,000 MMT of CO2e from fossil fuel use.ii To solve our GHG problem, we must cut back our consumption of fossil fuels. Providing energy substitutes that emit lesser amounts of fossil carbon is the only way to mitigate climate change. This big problem requires lots of solutions, but we won’t get anywhere if we don’t slow down our consumption of fossil fuels.
The good news is that we have plenty of energy we can use to replace fossil fuels. We don’t have to extract fossilized carbon to power our homes and our economy, because the sun provides more than enough energy to meet our needs every day. We are starting to realize this as we install more photovoltaic solar panels and windmills that economically convert solar energy into electricity. These technologies are replacing coal and natural gas fired electricity generation with carbon neutral energy. This is how we will fight and win part of the battle to mitigate climate change and reinvigorate our economies.
But how will we replace the petroleum which accounts for more GHG emissions than coal or natural gas?iii The answer is the same. The answer is carbon neutral solar energy. Nature stores solar energy in biomass. Plants use solar energy to form chemical bonds between carbon, hydrogen, and oxygen. We can access this energy to displace petroleum. Remember that the carbon in biomass will return to the atmosphere anyway. With that in mind, it would be foolish not to harvest this carbon-neutral energy. We can use the energy stored in biomass to power our economy, create jobs, and reduce carbon emissions.
The fats and oils used to make biodiesel are nature’s densest way of storing solar energy. Biodiesel also happens to be the easiest way to slipstream combustible biomass into our existing fleet of diesel engines. During every new planting season, growth of the next crop absorbs all of the carbon emitted when burning biodiesel. When we quantify the carbon benefit of biodiesel, we include the fossil fuel inputs used to grow plants and power trucks and tractors and biodiesel conversion facilities. If we transition those inputs to renewable energy, biodiesel could be 100% carbon neutral. As it stands today, biodiesel reduces GHGs by 81%iv compared to using petroleum diesel. This carbon benefit occurs because biodiesel provides energy that can be used in place of diesel fuel. Keeping fossil carbon in the ground and out of our atmosphere is the solution to climate change. The National Biodiesel Board has a goal to displace 10% of our on-road diesel fuel use by 2022. Achieving this will generate carbon reductions that cannot be gained in any other way. Replacing fossil carbon with renewable carbon will compliment conservation and improvements in efficiency.
Carbon 201 Biofuels and the Food Supply
Any strategy to mitigate climate change is incomplete without providing alternative sources of energy that can be used to displace fossil fuels. Still, there’s nothing wrong with trying to improve the carbon storage in trees and other living things. Living things provide only temporary carbon storage, but every little bit helps in this overwhelming challenge we have created as a result of fossil fuels. Humans have a big impact on land use change.
Between 2004 and 2011, the global footprint of agriculture shrank by 60 million acres. This gave way to 19 million acres of additional forestsv, which is good even if the remaining 41 million acres may have been gobbled up by development. The fact that we are growing in population and affluence, yet shrinking the footprint of agriculture provides a clue to better land use management. I propose that the best way to manage land use for total GHG benefit is not to manage agriculture for carbon, but to manage agriculture for nitrogen.
Nitrogen is key to our food supply, because nitrogen makes up amino acids and protein that we must have in our diet. Protein is the limiting factor in our food supply and the most expensive macronutrient in our diet. More efficient production of protein is what enabled agriculture to shrink by 60 million acres between 2004 and 2011. There are GHG implications stemming from the production and use of nitrogen fertilizer, but more impactful is the efficient production of high amounts of protein per acre. Protein per acre determines the footprint of agriculture and the carrying capacity of the food supply. You can’t sustain human life without protein input from plants. Even if you eat meat, the protein originates from plants grown as livestock feed.
Another reason I say we should manage agriculture for nitrogen instead of carbon is because when we grow protein to feed the world, we get more fats and carbohydrates than we can eat. All plants are really good at storing solar energy in carbon bonds. Not that many plants are really good at producing high amounts of protein. Solar energy is stored in the carbon bonds of starches, sugars, cellulose, fats, and oil. If we make protein the priority, and select plants that are efficient users of nitrogen, we will automatically satisfy the global need for all the macronutrients in our diet. All the fats and carbohydrates that are left-over can be used to provide energy that replaces fossil fuels.
This is the formula that makes biodiesel America’s first advanced biofuel. The fats and oils used to make biodiesel are byproducts of protein production – either from the excess oil produced by high protein soybeans or animal fats salvaged from beef, pork, and poultry production. We didn’t grow any of these things just so we could make biodiesel. We grew these things to satisfy protein demands of our food system. As we look to increasing our use of renewable fuels in order to displace larger volumes of fossil fuel, maybe someday we will grow plants specifically for their energy content – but even when we do, we will need to make sure that protein needs are satisfied first.
Summing up, here are three rules I recommend to achieving sustainability:
- Seek efficient protein production.
- Reduce our use of fossil fuels.
- Protect biodiversity and the habitats and natural systems that support life.
Pop Quiz: Which form of energy does all of these?
Don Scott serves as the Director of Sustainability for the National Biodiesel Board.