Energy 101: Carbon and Climate

Updated: October 11, 2023

By Drew Schiavone

The Earth’s atmosphere contains gases that help to warm the planet and support life by absorbing and emitting radiation (greenhouse effect). One of these gases is carbon dioxide (CO₂). In a completely natural world, CO₂ levels are balanced by natural processes. Plants absorb CO₂ and produce oxygen (O₂) – while animals use O₂ and produce CO₂. However, as fossil fuels are burned, additional CO₂ is released into the atmosphere. The amount released is more than what can be naturally balanced and the concentration of several important greenhouse gases (GHGs) have increased by about 40% since industrialization began. In addition to CO₂, other GHGs considered important are methane, nitrous oxide, hydroflorocarbons, perflurocarbons, and sulfur hexafluoride.

These higher concentrations of GHGs may enhance the greenhouse effect, contributing to increased temperatures and changed climates on Earth. While the topic of climate change and global warming remains controversial, it is clear that GHGs help to warm the planet while human activities, such as burning fossil fuels, create additional greenhouse gases. Therefore, many public policies have been enacted in an attempt to reduce the net amount of additional carbon released into the atmosphere.

Fossil fuels supply 84% of the primary energy sources consumed in the U.S. and they produce 99% of CO₂ emissions. If total GHGs are considered, about 87% of 2009 emissions in the U.S. came from energy-related sources. Electricity generation and transportation are the two largest sources of energy-related greenhouse gas emissions. According to EIA, the electrical power industry currently emits the most greenhouse gas. However, petroleum is the fossil fuel that emits the most CO₂.

Because energy is used in homes, vehicles, and manufacturing products, almost all U.S. consumers are associated with GHG emissions. Recently, many organizations have tried to help consumers understand the extent to which they contribute to the emission of GHGs (especially carbon) by estimating the “footprint,” or carbon impact, of each consumer. These calculations are often referred to as “carbon footprints.” An example of a residential calculator developed by the Environmental Protection Agency can be found at: EPA: Household Carbon Footprint Calculator.

Note: there are no defined standards for calculations. The differences between each calculator are usually attributed to the assumptions being made in the calculation. While the assumptions made in calculations remain a controversial topic, these tools can, however, help you to better understand your greatest impact on carbon emissions.

Carbon sequestration is the permanent storage of carbon in geologic (i.e. underground) or terrestrial (i.e. in soils and plants) systems. As such, terrestrial carbon sequestration is defined as either the net removal of CO₂ from the atmosphere or the prevention of CO₂ net emissions from the terrestrial ecosystems into the atmosphere. Enhancing the natural processes that remove CO₂ from the atmosphere is thought to be one of the most cost-effective means of reducing atmospheric levels of CO₂. Many ecosystems in Maryland represent viable options for terrestrial carbon sequestration such as forest lands which include below-ground carbon and long-term management and utilization of standing stocks, understory, ground cover, and litter. Agricultural lands may also improve terrestrial carbon sequestration through crop lands, grasslands, and range lands, with emphasis on increasing long-lived soil carbon. At this time, the U.S. does not actively regulate the GHG emissions, so the market for sequestered carbon is limited. Despite these issues, carbon sequestration is receiving significant attention in Maryland.