Venus – the Queen of Greenhouse

Dmitriy Titov Max-Planck Institute for Solar System Research

ESAC, Spain27 April 2010

Temperatures on Mars, Earth and VenusTemperatures on Mars, Earth and Venus

I___ I___ T ~ 500 KT ~ 500 K __I __I

Solar Solar radiationradiation

ThermalThermal

emissionemission

Basics of the greenhouse effectBasics of the greenhouse effect

Wavelength, microns

10 µm0.5 µm 1 µm 5 µm

Absorption bands of the atmospheric gasesAbsorption bands of the atmospheric gases

Greenhouse effect on Greenhouse effect on terrestrial planetsterrestrial planets

Venus – Venus – 500K500K

Mars – Mars – 5K5K

Earth – Earth – 40K40K

Contribution of the atmospheric components to Contribution of the atmospheric components to the greenhouse effect on Venusthe greenhouse effect on Venus

Temperature, K

COCO2 2 – 460K– 460K

HH22O – O – 220K220KClouds – Clouds – 100K100K

H2SO4 Clouds

CO2

H2O

TTeffeff ~250 K ~250 K Ts ~ 750 KTs ~ 750 K

Bullock, 2007

Venus climate perturbations: greenhouse effect and Venus climate perturbations: greenhouse effect and sensitivity to Hsensitivity to H22O and SOO and SO22 variations variations

FFH2OH2O ~ 30 ppm: non-equilibrium wrt escape t ~ few 100 MY ~ 30 ppm: non-equilibrium wrt escape t ~ few 100 MY

FFSO2 SO2 ~ 150 ppm: non-equilibrium wrt surface buffer t ~ 30 My ~ 150 ppm: non-equilibrium wrt surface buffer t ~ 30 My

Both HBoth H22O and SOO and SO22 are cloud forming gases are cloud forming gases

Bullock & Grinspoon, 2001

Water on Earth and VenusWater on Earth and Venus

Similar volatile inventories at originSimilar volatile inventories at origin

Present water amount: HPresent water amount: H22OOVENUSVENUS ~ 10 ~ 10-5-5 H H22OOEARTHEARTH

Deuterium enrichment: (D/H)Deuterium enrichment: (D/H)VENUSVENUS ~ 150 (D/H) ~ 150 (D/H)EARTHEARTH

Water: its properties and role in climate evolution Water: its properties and role in climate evolution

ThermodynamicsThermodynamics

high condensation temperature

existence of all 3 phases at “normal” temperatures

Large reservoirs in the inner Solar SystemLarge reservoirs in the inner Solar System

Strong greenhouse agent in vapour phase Strong greenhouse agent in vapour phase

When liquid – ability to dissolve COWhen liquid – ability to dissolve CO22 followed by its followed by its

convertion to carbonatesconvertion to carbonates

Easy escape to space from the top of the atmosphereEasy escape to space from the top of the atmosphere

Earth-like planet: greenhouse effect and water loss (2)Earth-like planet: greenhouse effect and water loss (2)

Solar flux, Solar flux, W/mW/m22

Ts < 100 C Ts < 100 C Ts ~ 100 C Ts >> 100 C

400400300300 625625

Venus now

Venus now

Runaway Runaway greenhousegreenhouse

Moist Moist greenhousegreenhouse

Ingersoll

Ingers

oll

limit

limit

Earth now

Earth now

Kasting, 1988

Habitability zone in the Solar SystemHabitability zone in the Solar System

MARS EARTH VENUS MERCURY

Distance, AUDistance, AU

1.0 0.72 0.391.52

Runaway greenhouseRunaway greenhouseParadiseParadise

Global Global fridgefridge Greenhouse Greenhouse

bathbath

Plasma environment and Plasma environment and escape processesescape processes

H+, O+, He+

Venus

Earth