Lake Kivu Overview

• Located between Democratic Republic of Congo and Rwanda
• 9th deepest lake in world
• Appears innocent in photos but extremely dangerous
• Home to 60% of world's lakes are in Canada, but none as dangerous as Lake Kivu

Historical Limnic Eruptions

• Lake Maloon (August 15, 1984)
  • First recorded limnic eruption in history
  • Local people heard loud noise, saw gas cloud from lake
  • 37 people died with skin discoloration
  • Initially thought to be terrorist attack
• Lake Nyos (1986)
  • Similar but more catastrophic event 2 years later
  • Occurred at night
  • 25 meter high tsunami hit opposite beach
  • Lake turned deep red
  • 1.2 cubic kilometer toxic CO2 gas cloud migrated to villages
  • Over 1,700 people died
  • People affected up to 25 kilometers away
  • Thousands of cattle and wild animals also died

Scientific Mechanism of Limnic Eruptions

• Lakes become saturated with gases (CO2, methane)
• CO2 sources: volcanic gas below lakes or organic material decomposition
• Behaves like unopened soft drink - CO2 dissolved in water
• Higher pressure at bottom allows more CO2 dissolution
• Cooler water at bottom also dissolves more CO2
• Lake becomes extremely unstable when saturated
• Trigger events: volcano, earthquake, explosion
• Process: saturated water pushed higher → low pressure can't contain CO2 → bubbles form → gas column erupts → suction pulls bottom water up → runaway CO2 loss → explosion
• CO2 denser than air, sticks to ground, pushes breathable air up

Lake Kivu Threat Assessment

• Has exact same symptoms as previous two lakes
• Much bigger than previous lakes
• Contains much more gas buildup:
  • 65 cubic kilometers of methane
  • 256 cubic kilometers of CO2
• 2 million people live around lake shores
• All lives would be in jeopardy if eruption occurred
• Geologists found evidence of local extinction events every 1000 years
• Pattern suggests lake explodes approximately once per millennium

Current Mitigation Efforts

• Rwandan government extracts methane for energy purposes
• Probably not enough extraction to prevent disaster
• Previous two lakes had pipe systems installed to release gas above surface
• Lake Kivu too big for same solution to be practical
• Releasing gas would equal 2% of annual human fossil fuel emissions
• Would cost millions of dollars
• Neighboring countries may not be willing to spend
• No clear solution currently exists
• May only be matter of time until another disaster

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