Environmental Impact of Volcanism Caspar Ammann, NCAR

1
Climate System Response to the Toba Mega Eruption

• Caspar Ammann, NCAR
• Alan Robock, Rutgers
• Sam Levis, NCAR

2
Toba Mega Eruption, 74ka
Oppenheimer, 2002

• 2800 km3 DRE (Pinatubo 9)
• 100-10,000 Mt Sulfate Aerosol (Pinatubo 30 Mt)
• Erupted in 14 days (Rose and Chesner 1990)
• Sulfur deposit in Greenland over 6-7 years

3

• 1000-yr Stadial, with Toba signal close to the
  transition
• Low-res records Gradual decline underway
• Climate signal in low lat oceans 1K
• (Huang et al. 2002)

4
change
5
(No Transcript)
6
Surface Temperature Response (Years 1, 5, 15, 38)
7
Snow Cover Year 1
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
Toba Results

• Zielinski

• Given coupled GCM
• Initiation of Glacial Period?
• No
• Complete loss of vegetation?
• No, coastal areas!- strong regional
  differences- C3 grass fingerprint
• Global Cooling
• - Up to 10 degrees- but quick recovery High
  res. Records required

15
Outlook

• Importance for coupled earth system model
• Importance for interactive chemistry
• Stratospheric aerosol formationboth formation
  speed and removal
• Size distribution of particles
• Oxidation state of atmosphere SO2 lifetime
  andreduction of peak forcing, but possible
  temporal extension
• Test climate effect on deposition

16
Sulfate Deposition Sensitivity to Climate?
Oman / Gao et al. (in review)