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Earth is more than one Planet: Lessons from Earth history Giada Arney NASA Goddard Space Flight Center
Earth is more than one Planet:Lessons from Earth history
Giada ArneyNASA Goddard Space Flight Center
Image by Maggie Turnbull
4
vegetation
carbon dioxide
methane
oxygen and ozone water
vapor
optical nearinfrared
wavelength
NASA EPIC/DSCOVR
Earth is more than one planet
6(now)
13%
39%
48%
A couple examples…
7(now)
13%
39%
48%
PhanerozoicPrecambrian
EonsEarth’s history
Hadean Archean Proterozoic
4500
3500
2500
1500
500 0
4000
3000
2000
1000
toda
y
history of oxygen
Reinhard et al. (2017)
O2 virtually absent (e.g. Farquhar et al. 2001)
PhanerozoicPrecambrian
EonsEarth’s history
Hadean Archean Proterozoic
4500
3500
2500
1500
500 0
4000
3000
2000
1000
toda
y
no O2 but…
likelyabundant CH4
(e.g. Ueno et al. 2006; Kharecha et al. 2005)
methanogenesiscarbon dioxide + dihydrogen → methane + water CO2 + 4 H2 CH4 + 2 H2O 13
http://metanogen.biotech.uni.wroc.pl/
serpentinizationOlivine + water + carbonic acid → serpentine + magnetite + methane(Fe,Mg)2SiO4 + n·H2O + CO2 → Mg3Si2O5(OH)4 + Fe3O4 + CH4 14
http://www.whoi.edu/
I have abundant methane
methane produced serpentinization
(non-life)
High CH4 production rates life?
(Krissansen-Totton et al 2018)
Abundant CH4, but low
production rate
Less CH4, but high production rate
I have a haze!
PhanerozoicPrecambrian
EonsEarth’s history
Hadean Archean Proterozoic
4500
3500
2500
1500
500 0
4000
3000
2000
1000
toda
y
late Archean intermittent
hazy periods?e.g. Trainer et al. (2006)Haqq-Misra et al. (2008)
Domagal-Goldman et al. (2008)Wolf & Toon (2010)Zerkle et al. (2012)
Arney et al (2016, 2017, 2018)Izon et al. (2015, 2017)
Climate:Haze cools surface by 20-30 K
Habitability can be maintained in the presence of other greenhouse gases (e.g. 2% CO2)
UV shielding:Haze is a good
UV shield
blocks 97% of UVC radiation
reflection spectra
thin haze
thick haze
Haze extinction
CH4
H2O
CH4
CH4
H2O H2O
CH4
H2OCH4
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Earth with pCO2 = 0.018 bar, 1 bar total pressure
Arney et al. (2016)
PhanerozoicPrecambrian
EonsEarth’s history
Hadean Archean Proterozoic
4500
3500
2500
1500
500 0
4000
3000
2000
1000
toda
y
history of oxygen
Reinhard et al. (2017)
O2 level possibly as low as 0.1% of the present day level (Planavsky et al. 2014)
PhanerozoicPrecambrian
EonsEarth’s history
Hadean Archean Proterozoic
4500
3500
2500
1500
500 0
4000
3000
2000
1000
toda
y
low O2 but…
likely still able to detect ozone
e.g. Reinhard et al. (2017), Olson et al. (2018), Schwieterman et al. (2019)
25Olson et al. 2018
biological seasonal ozone variations
Olson et al 2018
