Is any Human Activity Really Carbon Neutral?
It makes people feel good when they think they are doing something that is carbon neutral. But is anything we do carbon neutral? Carbon neutral is a term that has quickly become very popular. You might call it the latest trendy term of the self appointed “environmentally enlightened”.
Carbon neutral refers to anything that does not increase or decrease the amount of carbon in the atmosphere. This term can refer to both human and non human activity. The burning of fossil fuels are a main target of opposition from people using this term since fossil fuels are considered to be very much not carbon neutral.
Renewable energy sources like biofuel are often credited for being carbon neutral. The burning of biofuel does release carbon dioxide into the atmosphere but since it comes from plants that absorbed the carbon from the atmosphere there is no net increase of carbon in this process. When you cut down a tree in the forest and burn it in your fireplace you do release the carbon from the tree into the atmosphere. But the idea is that the new tree that takes its place in the forest will absorb that CO2 as it grows. Therefore burning wood is considered to be carbon neutral.
So back to our original question, is anything we do really carbon neutral? Burning biofuel makes us feel good because we think we are being carbon neutral. And with humans feeling good is what is most important to us so as long as we believe we are doing something good that’s what matters to us.
But is there really a benefit to burning biofuel as being carbon neutral? In a perfect world biofuel could be carbon neutral but in our world it is not carbon neutral. In most cases biofuel needs to be processed and transported. In most cases these processes are powered by burning fossil fuels. From the chainsaw that cut the tree down to the truck that hauls the material. On a large scale there are many behind the scenes processes that are involved in producing that fuel. Not only the actual material processing, consider all the people that have to drive to work. From the people who do the growing and harvesting to those who work in the processing plant and even the office workers or the people in the advertising agency that was hired to promote the product. They probably drove cars using petroleum and the lights, computers, telephones they use probably run on coal generated electricity.
Or consider solar energy. We may think of it as being carbon neutral but how much fossil fuel is used in producing the solar panel? The raw material has to be mined, processed, transported and on and on. Plus all the people who have to drive to work every day and who use fossil fuels in their daily work activities the same as with biofuel. So the question is will a solar panel produce enough electricity to make up for al the energy that was used to build it? I don’t know the answer to that but it would be interesting to see the numbers.
So in reality none of these so called carbon neutral things that we like to call carbon neutral are really carbon neutral. Some are closer to being carbon neutral than others but not actually carbon neutral. So maybe if a carbon neutrality scale was created consumers could select products that are closer to carbon neutral than others instead of just blindly accepting things as being carbon neutral. Instead we can accept that we are only being partly carbon neutral. Partly carbon neutral is probably a good start and better than the alternative.
Now look at your own body. If you only ate food that you found or hunted in the wild like your early ancestors did you could probably be considered carbon neutral. But in modern society production of the food we eat has a huge carbon footprint so even human power is far from being carbon neutral.
In some cases some fuels may actually be carbon neutral or even contribute to a carbon sink that actually absorbs more CO2 form the atmosphere than it released. An example could be wood pellets that are produced from waste products created in forest enhancement projects. Imagine a project where small low grade slow growing trees are harvested and made into pellets for fuel. The forest is then replanted with fast growing trees that will grow to 5 times the size of the low grade trees and absorb many times more CO2 from the atmosphere than the original trees would.
That brings up another trendy term which is “carbon sink”. A carbon sink refers to anything or any activity that removes carbon from the atmosphere and stores it instead of releasing it. A carbon sink causes a net decrease in atmospheric carbon. Old growth forests and especially tropical rain forests were once considered to be a carbon sink that continually absorb CO2 and release oxygen for us to breath. That’s how the tropical rain forests sometimes get called the lungs of the earth. Although we now now this is not the case and natural forests typically do not absorb any net amount of CO2 and do not provide us with oxygen.
Forest Harvesting and the Carbon Neutral Debate
We now know that old growth forests including the tropical rain forests are usually not carbon sinks but are instead carbon neutral. A growing forest is a carbon sink but once a forest reaches maturity it reaches an equilibrium where dead plant material accumulates and decays in a forest at a rate that is close to equal the growth of new plant material.
As the dead plant matter decays oxygen is absorbed from the atmosphere and CO2 is released by the organisms that consume the material. The amount of CO2 that an old growth forest produces and releases is usually close to equal. This makes old growth forests carbon neutral. Old growth forests including the tropical rain forests also do not supply us with oxygen like we once believed they did since the decaying plant matter consumes as much oxygen as the trees produce.
On the other hand forests used for timber production are a carbon sink. Forests used for timber are periodically harvested and renewed so they never reach that stagnant equilibrium. Instead of trees getting old and dying and decaying and releasing their CO2, the woody material is removed from the forest to be used for making products like lumber. New trees are planted in their place and will continue to vigorously absorb CO2 from the atmosphere. The carbon that the previous trees removed from the atmosphere then remains stored in the form of lumber in things like your home instead of being released into the atmosphere.
As a forest is harvested there is an initial release of carbon in the process as the limbs and other unused material called slash is burned or decays so the process is not perfect but the removal of permanent solid wood products equates to a net removal of carbon from the atmosphere.
A forest that is consumed by a catastrophic forest fire that kills the trees can also be carbon neutral or a carbon sink depending on whether the dead trees are salvaged or not. The fire releases some of the carbon from the forest CO2 as it burns the dead material, leaves, needles and small twigs. When a forest fire burns and kills the trees most of the woody material from the green trees will not burn and are left standing after the fire. These trees will decay over time releasing carbon into the atmosphere for decades and sometimes centuries. As new trees grow in their place they will eventually absorb that carbon so eventually the process becomes carbon neutral.
If the dead trees are harvested quick enough they can be cut into lumber that can be made into products like your home instead of being left to decay and release their carbon into the atmosphere. In this case the new forest that is replanted after harvest will absorb CO2 from the atmosphere as they grow. Since the dead trees are no longer there decaying and releasing CO2 the process becomes a carbon sink.
Or Maybe it is all Carbon Neutral After all
The problem with this whole debate is in reality we may think we understand how the carbon cycle and global warming work. In reality we probably don’t. For all we know the Earth may be naturally carbon neutral no matter what we do. There may be processes we don’t know about that keep CO2 in the atmosphere at safe levels and that’s why levels are in the ranges they are in. Or maybe not.
Either way I think it is time both sides of the debate stop pretending we know what’s going on. Global warming is a theory but one that may be worthy of debating and paying attention to. The opponents of the theory would probably take it more seriously if the global warming believers stop treating it like a religion.