PLANET EARTH: FRAGILE AND EVER-CHANGING Ashok Sahni INSA
description
Transcript of PLANET EARTH: FRAGILE AND EVER-CHANGING Ashok Sahni INSA
PLANET EARTH:
FRAGILE
AND
EVER-CHANGING
Ashok Sahni
INSA
Senior Scientist
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!!