Photo above: Driving across the countryside of Kurdistan region in Northern Iraq, an abundance of oil production facilities and gas flaring sites are observed releasing carbon in the form of methane, carbon dioxide, and many times, black carbon soot into the atmosphere due to incomplete combustion. Captured 2021, All Rights Reserved – Chris Hammond.
Carbon, in its many forms, is a fundamental component of organic matter (Thorme, 2024). Its presence is ubiquitous; it is a building block for organic molecules, and provides a “backbone” allowing for bonding other elements to form complex structures of life (NOAA, 2019). It can be found almost everywhere, for example, within the air we exhale as carbon dioxide (CO2), in fossil fuels, within in the Earth’s biosphere, oceans, soils, rocks, and sediments. In the context of climate, carbon in the atmosphere also affects Earth’s ability to release heat (Thorme). In fact, the two strongest greenhouse gases in the atmosphere, carbon dioxide and methane (CH4) (both carbon-based), contribute to the warming of the planet.
Anthropogenic carbon dioxide and methane are emitted through processes such as burning of fossil fuels, deforestation, agricultural practices, and industrial activities like cement production, releasing carbon at a pace that exceeds the rate at which natural sinks can absorb it within the existing natural carbon lifecycle (EPA, 2025). Because greenhouse gases trap infrared radiation in the atmosphere, their thermal effect also increases in relation to their concentration in the atmosphere, thereby accelerating planetary warming. With increased planetary warming, as was discussed in section 1.5, Earth’s climate and weather patterns are altered, affecting and intensifying extreme weather events and their related, often cascading, socioeconomic consequences.
Problematically, carbon dioxide can remain in the atmosphere for years to centuries or longer (MIT Climate Portal, 2023) and can be described as having a long tail due to the slow process of removal from the atmosphere (Lord et al., 2016). Conversely, although methane’s atmospheric lifetime is not as long, it is no less of a problem, as it is 28 times more potent than carbon dioxide at trapping heat in the atmosphere (EPA 2023), thereby significantly contributing to planetary warming.
Considering this, briefly then, how is carbon removed from the atmosphere? And what can we do about it? In the natural carbon lifecycle, methane is primarily removed by chemical oxidation, while carbon dioxide is removed by way of carbon sinks (Moseman, 2022). While significant volume of CO2 is absorbed on a scale of ~350 billion tons per year, anthropogenic emissions have tipped the balance and contribute more than can naturally be absorbed (Moseman). Biological uptake assists in removal, where plants (i.e. trees) and algae may absorb it during photosynthesis, storing it as biomass (Riebeek, 2011); oceans, which act as sinks, dissolve CO2 into seawater, but problematically, as the ocean absorbs greater volumes, it also contributes to acidification due to the pH difference, affecting sea life and aquatic habitats (Riebeek). Further, as waters warm and acidify, they reduce its capacity to absorb CO2 while concurrently disrupting oceanic ecosystems. With that said, technological methods of dealing with CO2 in the atmosphere exist and are being advanced, including carbon capture and sequestration, as well as carbon dioxide removal (NOAA Science Council, 2024).
Below, I’ve put together a quick comparative table of the two top greenhouse gas properties in relation to the atmosphere and climate change. The data clearly indicate that the atmospheric concentration of these two gases are increasing at rates unprecedented in history.
| Carbon Dioxide (CO2) | Methane (CH4) | |
| Sources | • Burning of fossil fuels • Solid waste • Deforestation • Energy production • Cement production (EPA, 2025) | • Production/transport of coal • Natural gas, oil and fossil fuel extraction • Agriculture (ex, livestock enteric methane) • Landfill decomposition (EPA, 2025; NASA, n.d.) |
| Atmospheric concentration | • Oct 18th, 2025: 425.10ppm For context (1 month avg) • Oct 2024: 424.03ppm • Oct 2000: 369.44ppm • Oct 1960: 316.84 ppm (Lindsey, 2025) | • May 2025: 1933.54ppb (latest data from NOAA) • Oct 2024: 1941.02 ppb • Oct 2000: 1777.08 ppb • Oct 1983: 1644.79 ppb (Lan et al., 2025) |
| Warming Potential | Baseline | 28 x more than CO2 (EPA, 2025) |
| Atmospheric lifetime | Decades to centuries, in some estimates, 10,000+ year long tail (Moseman, 2022) | Approximately 12 years (Mitloehner, 2020) |
Reference List
EPA – Environmental Protection Agency. “Importance of Methane.” US EPA, 1 Nov. 2023, www.epa.gov/gmi/importance-methane. Accessed 18 Oct. 2025.
EPA – United States Environmental Protection Agency. “Overview of Greenhouse Gases.” US EPA, 16 Jan. 2025, www.epa.gov/ghgemissions/overview-greenhouse-gases. Accessed 18 Oct. 2025.
Lan, X, et al. “Trends in Globally-Averaged CH4, N2O, and SF6 Determined from NOAA Global Monitoring Laboratory Measurements.” Gml.noaa.gov, Sept. 2025, doi.org/10.15138/P8XG-AA10. Accessed 18 Oct. 2025.
Lindsey, Rebecca. “Climate Change: Atmospheric Carbon Dioxide.” Climate.gov, National Oceanic and Atmospheric Administration, 21 May 2025, www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide.
Lord, N. S., et al. “An Impulse Response Function for the “Long Tail” of Excess Atmospheric CO2 in an Earth System Model.” Global Biogeochemical Cycles, vol. 30, no. 1, Jan. 2016, pp. 2–17, agupubs.onlinelibrary.wiley.com/doi/10.1002/2014GB005074, https://doi.org/10.1002/2014gb005074. Accessed 18 Oct. 2025.
MIT Climate Portal. “How Do We Know How Long Carbon Dioxide Remains in the Atmosphere? | MIT Climate Portal.” Climate.mit.edu, 17 Jan. 2023, climate.mit.edu/ask-mit/how-do-we-know-how-long-carbon-dioxide-remains-atmosphere. Accessed 18 Oct. 2025.
Mitloehner, Frank. “Why Methane from Cattle Warms the Climate Differently than CO2 from Fossil Fuels.” CLEAR Center, 7 July 2020, clear.ucdavis.edu/explainers/why-methane-cattle-warms-climate-differently-co2-fossil-fuels. Accessed 18 Oct. 2025.
Moseman, Andrew. “How Much Carbon Dioxide Does the Earth Naturally Absorb?” MIT Climate Portal, 4 Jan. 2022, climate.mit.edu/ask-mit/how-much-carbon-dioxide-does-earth-naturally-absorb. Accessed 18 Oct. 2025.
NASA. “Which Is a Bigger Methane Source: Cow Belching or Cow Flatulence?” Science.nasa.gov, science.nasa.gov/climate-change/faq/which-is-a-bigger-methane-source-cow-belching-or-cow-flatulence/. Accessed 18 Oct. 2025.
NOAA – National Oceanic and Atmospheric Administration. “Carbon Cycle.” Carbon Cycle, National Oceanic and Atmospheric Administration, 1 Feb. 2019, www.noaa.gov/education/resource-collections/climate/carbon-cycle. Accessed 18 Oct. 2025.
NOAA Science Council. “Carbon Dioxide Removal: NOAA State of the Science Factsheet.” NOAA Climate.gov, 19 Sept. 2024, www.climate.gov/news-features/understanding-climate/carbon-dioxide-removal-noaa-state-science-factsheet. Accessed 18 Oct. 2025.
Riebeek, Holli. “The Carbon Cycle.” NASA Earth Observatory, NASA Earth Observatory, 16 June 2011, earthobservatory.nasa.gov/features/CarbonCycle.
Thome, Kurtis. “Carbon Cycle and Ecosystems | Terra.” Terra.nasa.gov, 2024, terra.nasa.gov/science/carbon-cycle-and-ecosystems. Accessed 18 Oct. 2025.