Eight centuries ago, the world witnessed dramatic changes not only in politics and power, but also in the environment itself. During the 13th and 14th centuries, a significant and somewhat mysterious drop in atmospheric carbon dioxide was recorded, an event linked to the sweeping conquests led by Genghis Khan and his formidable Mongol armies. The profound impact of these invasions extended far beyond the battlefield, altering landscapes and even global climate patterns as vast populations were displaced and lands were reclaimed by nature.

Genghis Khan’s rise from obscurity in the harsh Mongolian steppes to ruler of a vast empire is a story filled with hardship, resilience, and unparalleled leadership. Much of his early life remains uncertain due to the absence of contemporary records, yet his actions would set in motion a legacy that shaped both the social and ecological history of the world.

Key Takeaways

A major drop in atmospheric CO2 occurred during the time of Genghis Khan.
Genghis Khan’s early life and the formation of the Mongol Empire are shrouded in limited written history.
His conquests left a lasting imprint on global history and the environment.

The Mysterious Medieval CO2 Drop

Changing Patterns of Medieval Carbon in the Air

During the transition from the 13th to the 14th century, global atmospheric carbon dioxide levels fell by an estimated 700 million tons. This reduction equates to more than twice the annual carbon emissions produced by the UK today.

Scientists regard this event as significant due to both its scale and the speed at which the atmospheric CO2 drop occurred. Researchers searching for patterns in historic climate events note its timing and note the lack of known technological explanations for such a decrease during that period.

Key facts:

Factor Detail Time Period 13th–14th Century CO2 Removed ~700 million tons Present-Day Comparison Over 2x current UK's annual emissions

Genghis Khan's Unintended Climate Consequence

The Mongol conquests led by Genghis Khan radically altered Eurasia’s landscape and population. In their campaigns, roughly 40 million people—more than a tenth of the world’s population at the time—died, mostly across regions stretching from China to Eastern Europe.

This depopulation created opportunities for previously cleared farmland and settlements to revert to forest and vegetation. Natural plant regrowth across such large areas absorbed carbon dioxide from the atmosphere through photosynthesis.

Sequence of events:

Mass deaths triggered by Mongol invasions
Large fields and settlements abandoned
Forests and vegetation regrew
Newly grown plants absorbed significant amounts of atmospheric CO2

This chain of events created a measurable carbon sink, which contributed to the drop in global CO2 during the medieval era.

The Extent and Impact of Genghis Khan's Campaigns

Massive Loss of Life

During the 13th century, Genghis Khan's military campaigns resulted in approximately 40 million deaths. This accounted for over 10% of the global population at the time. The sweeping destruction altered the demographic landscape across Asia.

Key Numbers:

Population Impacted Approximate Percentage of World Population Lost 40 million Over 10%

The human toll of these conquests remains among the largest in history. The aftermath left entire regions depopulated, dramatically reshaping societies and populations.

Environmental Recovery and Carbon Storage

The vast depopulation allowed previously cleared lands to be reclaimed by forests. As vegetation regrew on these lands, it absorbed a significant volume of carbon dioxide from the atmosphere. An estimated 700 million tons of CO₂ were removed during this period.

Notable Details:

The amount of carbon sequestered exceeded twice the UK's annual emissions.
This large-scale regrowth contributed to a measurable drop in atmospheric CO₂.
Such a natural reforestation event, linked directly to the aftermath of conquest, had far-reaching ecological effects.

Summary Table:

Impact Details Land regrowth Vast areas reforested CO₂ reduction ~700 million tons removed Comparison Over double UK's yearly carbon emissions

While unintentional, the rewilding of lands after Genghis Khan's campaigns significantly affected the environment, locking away carbon and even influencing global climate conditions at the time.

Genghis Khan’s Youthful Years

Unclear Beginnings and the Enigmatic Mongol Record

Much about Genghis Khan’s early life remains uncertain due to the absence of written records among the Mongols during his time. Most of what is known comes from the “Secret History of the Mongols,” an anonymous source whose reliability is still debated. Even the year of his birth is unclear, with estimates including 1155, 1162, and 1167, but 1162 is often accepted as the likely date.

No contemporary written records
Main source: Secret History of the Mongols
Birth year options: 1155, 1162, 1167
Common consensus: 1162

Temüjin’s Family Roots

Before taking the name Genghis Khan, he was called Temüjin. His father, Yesugei, was the chief of a leading tribe, while his mother had been taken from the Merkit—a practice not unusual on the steppe at the time. Temüjin was the eldest son, born into a respected clan, and spent his early years learning essential skills such as riding and hunting.

Family Member Role Noteworthy Fact Yesugei Father, Tribal Chief Leader of the Borjigin clan Mother Taken from Merkit Married to Yesugei, prominent position Börte Betrothed partner Fiancée from rival clan

Adversity and Survival in Early Childhood

Temüjin’s life changed dramatically after the poisoning and death of his father, Yesugei. This tragedy led to his family being expelled from their tribe by rivals, forcing them to survive in the harsh conditions of the Mongolian steppe without help. Scarcity of food led to internal family conflicts, eventually resulting in Temüjin killing his half-brother Behter to secure his position as the family’s leader.

Key obstacles faced:

Loss of tribal protection
Reliance on foraged foods and hunted game
Internal conflict over leadership and scarce resources

Despite these severe hardships, Temüjin’s abilities stood out. He quickly earned respect for his determination and leadership, even though this attracted the attention—and hostility—of his father’s former tribe, leading to his capture by rivals. This period of struggle marked the beginning of Temüjin’s relentless pursuit of power.

Ascent Amidst Mongolian Rivalries

Internal Struggles and Claim to Leadership

After the death of his father, Temüjin’s family was forced out of the tribe, creating stark hardship. With rival clans assuming power, Temüjin, only a young teenager, faced fierce internal competition, particularly with his half-brother. The dispute over family leadership led to a violent confrontation; Temüjin and his younger brother killed Behter, solidifying Temüjin’s position as family leader.

Family expulsion due to rival clan takeover
Siblings’ rivalry culminating in fratricide
Temüjin’s leadership confirmed after decisive action

Years of Hardship and Survival

Exiled to the harsh steppe, Temüjin and his family relied on foraging and hunting, often facing near starvation. The relentless environment tested their endurance, shaping Temüjin’s resourcefulness. These early struggles instilled a powerful drive to regain status and survival skills that would later define his strategies.

Challenge Temüjin’s Response Loss of family clan Assumed family leadership Scarcity of food Foraged and hunted Hostile conditions Adapted and persevered

Early Signs of Command

Even in his youth, Temüjin’s presence inspired respect among his peers. His decisions and actions were noticed by others in the surrounding clans. By his early teens, he was already recognized for his determination and ability to lead in adversity, traits that foreshadowed his later rise on a much larger stage.

Notable leadership characteristics:

Quick to make hard decisions
Gained loyalty after taking command
Demonstrated resilience and influence at a young age

Establishing the Mongol Empire

Building Partnerships and Facing Early Rivals

Genghis Khan, originally named Temüjin, navigated a landscape of shifting alliances and frequent battles among the Mongol tribes. Early on, his father's death left Temüjin and his family isolated, forcing them to survive independently in the harsh Steppe environment. This period demanded not only physical endurance but also negotiation skills, as Temüjin looked for ways to secure his family's place among rival clans.

Key moments during this time included his arranged marriage to Börte, intended to unite two tribes. However, internal rivalries and betrayals—such as his father’s poisoning and the subsequent expulsion of his family—highlighted the fragility of political ties. These early experiences set a pattern of both forming strategic partnerships and dealing ruthlessly with opposition.
Notable dynamics included:

Tribal leadership struggles after Yesugei's death
Betrayal and expulsion by the Tayichiud elite
Fratricidal conflict, resulting in Temüjin asserting sole leadership of his family

Genghis Khan’s Approach to Governance

Genghis Khan demonstrated an aptitude for leadership that extended beyond warfare. Despite the lack of a written language among the Mongols at the time, his actions established him as a respected figure by his teenage years. He relied on a combination of charisma, decisiveness, and calculated strength to unite disparate groups under his command.

His emerging model of rule featured: *Promotion based on loyalty and merit instead of just noble lineage
*Reunification efforts focused on bringing former enemies into his fold
*An understanding of the value of discipline and the need for structure in a region known for its volatility

Temüjin's approach reflected both practical necessity and foresight, establishing the groundwork for an empire that, at its peak, encompassed nearly a fifth of the world’s landmass and a quarter of its population.

The Environmental Legacy of Genghis Khan: How Mongol Conquests Changed Earth's Climate