# The Arctic's Yedoma: A Greenhouse Gas Powerhouse
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Chapter 1: Introduction to the Arctic Region
Traveling to the northernmost parts of our planet, one arrives in the Arctic—an area derived from the Greek term for bear. This unique geographical zone is predominantly composed of ocean, with around 60% of its territory covered by water, while the remaining 40% includes the northern fringes of various nations bordering the Arctic Ocean. Approximately four million individuals inhabit this region, with Murmansk in Russia being the largest city, home to around 300,000 people. A notable feature of the Arctic is Yedoma, a permafrost dating back to the Pleistocene era, characterized by its high organic content and ice composition ranging from 50% to 90%. The melting of Yedoma leads to the release of significant quantities of greenhouse gases into the atmosphere.
Large expanses of Yedoma are found in eastern Siberia and western Alaska, covering over a million square kilometers. What sets Yedoma apart from other types of permafrost is its elevated water content, extensive continuous area, and greater thickness, which collectively contribute to larger quantities of organic carbon. These traits render Yedoma particularly vulnerable to rapid melting and substantial greenhouse gas emissions.
As Yedoma degrades, it often gives rise to lake-filled thermokarst landscapes. The cyclical process of thawing and refreezing results in terrain marked by low hills and shallow depressions—known as ‘alas’—which become filled with meltwater. The melting of Yedoma transforms it into a crucial element of the Arctic carbon bomb.
Section 1.1: Understanding Permafrost
The term "solid ground" gains a new perspective when discussing permafrost. This mixture of ice and soil remains firm until temperatures rise above freezing, at which point it becomes a soupy, organic mass containing the decomposing remains of ancient flora and fauna. Permafrost is prevalent throughout much of the Arctic and constitutes about 24% of land in the northern hemisphere. Over time, it has transitioned from being primarily an engineering concern to a significant climate change issue.
Permafrost forms over centuries, during which living organisms become trapped in the frozen soil, halting the decomposition process. This interruption alters the natural carbon cycle, as plants and animals capture carbon during their lifetimes. Normally, when they die, bacteria break down their remains, releasing carbon back into the atmosphere as carbon dioxide and methane. However, permafrost acts as a time capsule, preserving carbon in the icy ground.
Currently, it is estimated that around 1,400 gigatons of carbon are locked away in Arctic permafrost, significantly more than the 850 gigatons present in the Earth's atmosphere. Among these, Yedoma deposits alone contain over 130 gigatons of carbon. As the Arctic approaches a critical tipping point, the carbon stored in Yedoma may be among the first to be unleashed into the atmosphere. While scientists have long been aware of the potential for carbon dioxide and methane emissions from melting Yedoma, recent studies indicate that these deposits are also significant sources of nitrous oxide (N2O), a potent greenhouse gas.
Section 1.2: The Role of Nitrous Oxide
Nitrous oxide ranks as the third most prevalent greenhouse gas contributing to global warming, with one ton of N2O possessing the same warming potential as approximately 300 tons of CO2. Unlike carbon dioxide, the primary source of N2O emissions is not fossil fuel combustion; rather, agriculture is responsible for about three-quarters of these emissions.
The significance of nitrous oxide cannot be overstated, yet it has often been overlooked in discussions surrounding climate change. Over the past four decades, N2O emissions have surged by 30%. The primary driver behind this increase is the widespread use of synthetic nitrogen fertilizers. Unfortunately, the narrative often places the blame on large oil companies, overshadowing the role of agricultural practices in this issue.
Given this context, the discovery that Yedoma serves as a substantial source of nitrous oxide is concerning. This issue arises from Yedoma's high ice content, which makes it susceptible to rapid thawing. In typical cold Arctic soils, the nitrogen cycle is slow, but when thawing occurs too quickly, the microbial populations responsible for producing N2O expand, while those that consume it diminish. This shift results in an excess of nitrous oxide being released into the atmosphere.
The Arctic is warming at a much quicker rate than the global average, raising the likelihood that it will reach a tipping point where natural processes—not human emissions—will trigger significant greenhouse gas releases, perpetuating permafrost melt. Once this tipping point is crossed, human intervention becomes ineffective, and the cycle continues until all 1,400 gigatons of Arctic carbon are converted into atmospheric carbon. In this scenario, the additional release of nitrous oxide from Yedoma will only accelerate the rate of permafrost melting.
Chapter 2: The Consequences of Yedoma Melting
The Arctic may emerge as one of the largest future contributors to greenhouse gas emissions and global warming.
Related Stories:
- Nitrous Oxide: The Overlooked Player in Greenhouse Gases
- Permafrost: A Ticking Carbon Time Bomb
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