Pluvials, droughts, the Mongol Empire, and modern Mongolia

Area of Science:

• Paleoclimatology
• Environmental History

Background:

• The rise of complex societies is often linked to climate change, but the role of favorable conditions is less understood.
• The 13th-century Mongol Empire, the largest contiguous land empire, lacks high-resolution climate data for its formative period.

Observation:

• A 1,112-year tree-ring reconstruction of water balance from central Mongolia was developed using Siberian pine (Pinus sibirica).
• This reconstruction correlates significantly with regional steppe productivity.
• Combined with temperature data, it reveals past climate conditions during the Mongol Empire's expansion.

Findings:

• The 13th-century Mongol Empire's expansion coincided with 15 consecutive years of above-average moisture and warm temperatures in central Mongolia.
• This wet period, unprecedented in 1,112 years, promoted high grassland productivity.
• The early 21st-century drought in central Mongolia was the hottest in 1,112 years.

Implications:

• Favorable climate conditions, including high grassland productivity, likely facilitated the rise of the Mongol Empire.
• Future warming in Inner Asia may lead to severe heat droughts, impacting modern Mongolia.
• Understanding past climate-society interactions is crucial for predicting future societal responses to climate change.