The Clean Air Act, 42 U.S.C. § 7401 et seq was adopted in the early 1960s to insure that business and industry does not spew pollutants into the air, causing harm to humans, plants and animals. Congress found that “the growth in the amount and complexity of air pollution brought about by urbanization, industrial development, and the increasing use of motor vehicles, has resulted in mounting dangers to the public health and welfare, including injury to agricultural crops and livestock, damage to and the deterioration of property, and hazards to air and ground transportation.” 42 U.S.C. § 7401(1)(2). Most of the permitting for new sources of pollution has been delegated to the states, subject to federal supervision. But in the end, it is EPA’s responsibility to implement the Clean Air Act.

When the Clean Air Act was adopted the primary focus was on toxins and particulate matter that was polluting the nation’s air. But for the last two decades or more, public policy makers have been concerned about not the “increasingly complex” air pollutants, but rather with the oldest and simplest – carbon dioxide as a “greenhouse” gas. Carbon dioxide is emitted by all animals and by dead plants as they decompose. It is sequestered by living plants as well as by dead plants that for some reason have not been allowed to decay. Because emission of carbon dioxide is ubiquitous, EPA for decades did not attempt to regulate it, even though there is an argument that any harm from other air pollutants may eventually pale by comparison to the harm from excessive emissions of carbon dioxide. In Massachusetts v. EPA, however, the U.S. Supreme Court held that if the EPA finds that there is a risk that carbon dioxide emissions endanger the health and welfare of current and future generations, it is required to regulate carbon dioxide emissions under the Clean Air Act.

The EPA finding of “endangerment” happened in December 7, 2009, setting up a requirement that EPA regulate greenhouse gas emissions. That has led to EPA attempting to issue a rule to do that – and assorted litigation and attempts by Congress to prevent EPA from acting. The tailoring rule for greenhouse gas emission is expected to be issued in July – and the fur that flies as a result will be the subject of future blogs. But the interesting thing to us at the moment is EPA’s decision to defer for three years any tailoring rule regarding CO2 emissions from bioenergy and other biogenic sources.  At the behest of the National Alliance of Forest Owners (NAFO) EPA agreed to the deferral so that it could study the science behind biomass energy production.

Why is this so much of an issue? The answer in part is because there are polar disagreements about it.

Carbon “cycles” occur on very different scales – ranging from geologic time, which is hundreds of millions of years, to the cycle of plant growth, death and decay of annual plants. Plants consume carbon dioxide and “sequester” it. The most extreme sequestration of carbon dioxide occurred with fossil fuels – which are the remains of plants that lived hundreds of millions of years ago. It is largely the release of a significant percentage of the carbon sequestered over those millennia in the century and a half since the first oil well was drilled in Pennsylvania that has given rise to the current concern about greenhouse gases and global warming. But, when a forest fire burns, or a farmer burns a grass field to rid it of weed seed and prepare it for replanting, or for that matter when annual crops are consumed by people or animals, that also releases carbon dioxide that was sequestered by plants. Combustion remains one of the central ways in which we release stored energy to turn it into forms of energy we can utilize – such as electricity. As a result, there are many people who believe that combustion (or digestion) of plants, either existing forest biomass or biomass coming from crops grown for the purpose, must be an important part of “sustainable” energy of the future.

The difficulty is that it turns out that most forests and most crops can become politicized, because both forests and crops have other “values” to a range of people. Annual crops can be grown that would take carbon dioxide out of the air in one growing season and put it back in the air through combustion to create electricity. Those crops can be replanted and use the sun’s energy to sequester the carbon again, year after year. Does that make combustion of annual crops “sustainable” and not a new source of air pollution? Well probably – but what if the land that is used to grow the annual crop is taken out of food production, leaving food shortages? Should that be encouraged? Obviously there are two sides to that question.

If a tree is grown on a 60-year rotation and then harvested, and those portions not used for solid wood products is burned to create electricity, is that sustainable? Arguably. But someone will argue that the tree was sequestering carbon for the previous 60 years, and the release of its carbon through combustion is a new source of carbon dioxide. But what if the land that the tree is grown on is promptly replanted, so that a new tree grows in its place – perhaps a faster growing tree that will sequester carbon more quickly?

Across the American West there are hundreds of thousands of acres of dead and dying trees as a result, among other things, of the suppression of forest fire through much of the 20th Century, and the unwillingness or inability to harvest trees in those forests when the forests became over-stocked. The over-stocking led to nature implementing its plans for natural succession of over-stocked forests, which was to allow the western pine beetle, an endemic insect in healthy forests, to become epidemic and kill the forest, after which nature will in due course allow lightening strikes to set the dead forests on fire, and a new forest to replace the existing dead forest. The dead trees are sequestering carbon – and in many cases have been sequestering carbon for a few hundred years. There is little doubt but that the sequestered carbon will ultimately be suddenly released in a forest fire, but for any particular part of the forest it is impossible to know whether the fire will be this summer or some decades from now. If instead of waiting for that inevitable sudden release, the dead trees are brought to a generating facility and burned now, is that a new source of carbon emissions? The answer any particular group gives to that question may have more to do with their concerns about harvesting of timber in general than it does with sustainable energy sources.

In the end, EPA will have to account for the fact that there are no perfectly sustainable sources of renewable energy. Wind power works when the wind is blowing – but we don’t have adequate ways to store it for when the wind isn’t blowing. It also results in some amount of harm to migratory birds, which did not evolve to expect large blades to be swinging in the pathways of their migration. Solar power also works when the sun is shining – but we don’t have adequate ways to store it and huge fields of solar collectors occupy land on which they displace ecosystems. Energy created by biomass or biogenic sources releases CO2 into the atmosphere. On the other hand, by any measure that CO2 can be sequestered again much faster than the CO2 that has been stored for hundreds of millions of years and is released when fossil fuels are burned. Because each of the sources of renewable energy has consequences that are capable of being politicized, EPA needs to expect that it won’t satisfy everyone, it will probably get sued regardless of what it does, and its job is to study all the issues and then make a decision in a timely manner.