PLANET EARTH:

FRAGILE

AND

EVER-CHANGING

Ashok Sahni

INSA

Senior Scientist

ashok.sahni@gmail.com

Earth is 4650000000 yrs old;

Life 3500000000 yrs,

Industrialization 300 yrs

Thermal Thermal Regime for a Regime for a Living PlanetLiving Planet

121C to-167C

Int. Space Stn.

VENUS

MARS

Fate of Earth?

Present Day Species Diversity

Snowball Earth Cryogenian ca. 650 ma

Icehouse earth 250 ma+Icehouse earth-present

Greenhouse earthGreenhouse earth

Disasters: Common, Disasters: Common, happening or yet to happen!happening or yet to happen! FREQUENCIES: ANNUAL TO KILO YEARS-SURFACE AND INTERNAL FREQUENCIES: ANNUAL TO KILO YEARS-SURFACE AND INTERNAL

(PLANETARY) STRESSES:-(PLANETARY) STRESSES:-

droughts, floods, landslides, earthquakes/tsunamis, volcanic droughts, floods, landslides, earthquakes/tsunamis, volcanic eruptions (within record of human civilization) eruptions (within record of human civilization)

FREQUENCIES: KILO YEARS OR MORE-SOLAR OR COSMIC FREQUENCIES: KILO YEARS OR MORE-SOLAR OR COSMIC FORCING:-FORCING:-

Climate Change-Solar radiations and water budget Climate Change-Solar radiations and water budget CO2/O2 /O3 enhancement and depletion.CO2/O2 /O3 enhancement and depletion. Cometary Impacts: ( note Tunguska 1908, Lonar, India Cometary Impacts: ( note Tunguska 1908, Lonar, India

(10kyr), Shoemaker –Levy on Jupiter 1994.(10kyr), Shoemaker –Levy on Jupiter 1994. Anoxia-relatively sudden decrease in atmospheric Anoxia-relatively sudden decrease in atmospheric O2O2

Ecosystem collapse-corals, tropical rainforests, large Ecosystem collapse-corals, tropical rainforests, large mammal niche etcmammal niche etc

Global Mean Annual Temperature Distributions at 0 & 100 myGlobal Mean Annual Temperature Distributions at 0 & 100 my

Long term Long term climate climate change change

perspective perspective ( myrs)( myrs)

Sun unusually active during last 50 yearsSun unusually active during last 50 years

Monthly

Sunspot no

Sea level riseSea level rise

Atmospheric O2 & C02 and evolution of life ( greening of the earth)Atmospheric O2 & C02 and evolution of life ( greening of the earth)

20.9%PAL

O26-8% PAL

CO2

Emiliania Emiliania huxleyihuxleyi

Cyclic Solar Energy input drives Cyclic Solar Energy input drives Earth’s Climate and Weather. Earth’s Climate and Weather. Greenhouse Gases . Greenhouse Gases .

Phyto (nanno)plankton are a Phyto (nanno)plankton are a powerful Biologic Pump to powerful Biologic Pump to drastically reduce Greenhouse Gas drastically reduce Greenhouse Gas CO2CO2

NASA’s Sea-viewing Wide Field-of-NASA’s Sea-viewing Wide Field-of-view Sensor (SeaWiFS) can view Sensor (SeaWiFS) can accurately measure Climate Change accurately measure Climate Change reflected by Phytoplanktonreflected by Phytoplankton

Climate change: ocean current gyreClimate change: ocean current gyre

Primrose: Decoration for man: landing pad for an insect!!Primrose: Decoration for man: landing pad for an insect!!

Adjusted for UV light as seen by insects

Dawkins: Greatest Show on Earth: 2009

ICEBERGS WILL

MELT!

BUT…

IF YOU WANT TO LIVE IN HARMONY WITH THE EARTH, TRY TO UNDERSTAND IT. NO NEED TO PANIC!!