climate change workshop – baesi – 5 th nov. 2011 © chevron 2011 the climate system – the...
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Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
The Climate System –The Attempt of an Overview
Miriam S. Andres
Carbonate Research & Development TeamETC-Chevron, San Ramon5th November 2011
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
The Geologic Record – A Matter of Time Scales
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The very Big and Long Picture
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
The Geologic Record –
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The Cool and Hot Stuff in-between
Observations • Major warm and cold periods, alternating• No run-away climate (yet).• The younger the more squiggles
Questions• Who are the climate players?• Climate change causes?• Are they always the same?• Why is there no run-away scenario?• What will happen in the future?
Example Time Intervals
Cretaceaus – super GreenhousePETM – rapid mega warmingYounger Dryas – back into the ice age
Holocene, the Anthropocene and the Future – Humans and Climate (this afternoon)
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011 4Courtesy of Richard Sedlock, San Jose State Univ.
The Players
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
The Climate System - Causes
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Ruddiman « Earth’s climate : past and future »
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
The Climate System – Causes-Players-Response
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William F. Ruddiman« Earth’s climate : past and future »W.H. Freeman and company, New York, 2002http://www.whfreeman.com/ruddiman/
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
The Climate System – Causes-Players-Response
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No human influence nor control
Ruddiman « Earth’s climate : past and future »
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
Earth’s Orbital Parameters
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1. Distance to the sun (=Eccentricity)2. Tilt of the Earth’s axis (=Obliquity)3. Wobbling of the tilt (=Precession)
Gravitational Interactions: Control amount and locus of incoming solar radiation!
closer
farther
1. Distance to the sun ≈ Eccentricity (deviation of ellipse from circularity)
Varies between 0 and 0.05; today at 0.0167 (quasi circular)Frequency: every 100’00 and 400’00 years
Effect: amount of radiation, locus of radiation
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3.
Tilt of Earth’s axis ≈ Obliquity : today at 23 degrees
Frequency: quite regular every 41’000 years
Effect: no tilt -> no seasonsSmall tilt -> mild summers, mild wintersToday: significant seasons, esp. at mid- to high latitudes
Wobble of the tilt caused by tidal forces exerted by moon-sun system onto solid EarthFrequency: ~ every 26’000 years
Effect: axis pointing towards sun -> one hemisphere with great seasonal difference, the other with milder seasons. At present: southern hemisphere seasons somewhat more extreme than ours.
Ruddiman « Earth’s climate : past and future »
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011 9
‘Natural’ Greenhouse Gases and Greenhouse Effect
• Sunlight brings energy into the climate system; most of it is absorbed by the oceans and land.
• Heat (infrared energy) radiates outward from the warmed surface of the Earth. Some of the infrared energy is absorbed by greenhouse gases in the atmosphere, which re-emit the energy in all directions. Some of the infrared energy further warms the Earth. Some of the infrared energy is emitted into space.
• Higher concentrations of CO2 and other "greenhouse" gases trap more infrared energy in the atmosphere than occurs naturally. The additional heat further warms the atmosphere and Earth’s surface. Water vapor = earth’s biggest GHG
• Albedo: White (ice/snow-covered surfaces reflect, black (ocean/land) surfaces absorb radiation
H2OCO2
CH4
OzoneN2O
Ruddiman « Earth’s climate : past and future »
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011 10
Plate Tectonics – Volcanoes – Mt. Building
Paleomap Project, Scotese, www.scotese.com
Plate tectonics- Distribution of
continents and oceans, esp. shallow seas
- Plate collisions cause mountain building and volcanism
www.nps.gov/yose/
USGS, R. Kimmel
Mountain Building- Immediate weathering of rocks- Transport in rivers to oceans- Deposition of Silica and Carbonates in
the ocean
Yose
mit
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PM
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Hele
ns,
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80
Volcanic Eruptions- emitting of ash, aerosols (SO2), water
vapor, CO2, HCl, HF into stratosphere (16-32 km)
-> heating of the stratosphere but cooling of the troposphere-> SO2 turns into Sulfuric acid which condenses to sulfate aerosol, which increase the earths albedo, thus cooling the troposphere. www.wikipedia.org
www.wikipedia.org
Ruddiman « Earth’s climate : past and future »
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
The Climate System – Causes-Players-Response
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No human influence nor control
Ruddiman « Earth’s climate : past and future »
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
The Geologic Record –
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The Cool and Hot Stuff in-between
Observations • Major warm and cold periods, alternating• No run-away climate (yet).• The younger the more squiggles
Questions Who are the climate players? Climate change causes? Are they always the same?• Why is there no run-away scenario?• What will happen in the future?
Example Time Intervals
Cretaceaus – super GreenhousePETM – rapid mega warmingYounger Dryas – back into the ice age
Holocene, the Anthropocene and the Future – Humans and Climate (this afternoon)
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
The Climate System– No runaway? Why
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Venus
‘Snowball Earth’
Ruddiman « Earth’s climate : past and future »
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011 14
Geologic Evidence in The Cretaceous Super Greenhouse
2009 (385 pp)
2000-1000 ppm; 8x pre-industrial levels
High sea level; abundant inundated shallow shelf areas. one-third of Earth's present land area was submerged
Ruddiman « Earth’s climate : past and future »
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011 15
The Cretaceous – Super Greenhouse ClimateWhy did it not get warmer and warmer?Earth’s Self-regulation
Ruddiman « Earth’s climate : past and future »
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
The Geologic Record –
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The Cool and Hot Stuff in-between
Observations • Major warm and cold periods, alternating• No run-away climate (yet).• The younger the more squiggles
Questions Who are the climate players? Climate change causes? Are they always the same?• Why is there no run-away scenario?• What will happen in the future?
Example Time Intervals
Cretaceaus – super GreenhousePETM – rapid mega warmingYounger Dryas – back into the ice age
Holocene, the Anthropocene and the Future – Humans and Climate (this afternoon)
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
Earth’s long-term climate future
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Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
Key Points on the Climate System● Earth’s climate: nothing as constant as change; on all time scales and in
all areas
● The Major Players: The Major External Causes:
● ‘Natural’ Greenhouse: critical to life on Earth
● Greenhouse:
amount of incoming solar radiation
albedo effect: fraction of solar radiation that is reflected
amount of IR radiation that escapes to space
● No run-away scenario because of positive and negative feedback loops evidenced multiple times in the geologic record
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Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
The Climate System – Causes-Players-Response
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William F. Ruddiman« Earth’s climate : past and future »W.H. Freeman and company, New York, 2002http://www.whfreeman.com/ruddiman/
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
Ocean Response
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Earth’s Oceans- cover 75% of the globe- absorb most of the rheat- adsorb most of the CO2
- precipitation of weathered ions, critical to climatic self-regulation
- moisture balance- ….
Ocean Currents =Coriolis effect+ tides + shoreline+ depth contours+ wind + temperature+ salt
density-driventhermo-haline circulation
Wind-driven circulation affects surface (upper 100–400 m) currents only.Density-driven circulation affects the entire ocean, include deep water.
The world ocean is a vast heat reservoir, storing more heat in its upperfew meters than the entire atmosphere does. Thus, changes in oceancirculation have significant, complex effects on climate.
www.wikipedia.org
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
Thermohaline circulation – THC-> Great Ocean Conveyor Belt
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www.cleanet.org
www.wikipedia.org
• Thermohaline circulation driven by differences in density = fct (temp+salt)
• The THC is a concept and most images and idealized version
• Main driver is cooling of surface water at high latitudes
• The THC and wind-driven circulation mix the world ocean setting up ‘the great ocean conveyor belt’ or ‘Meridional Overturning Circulation’ (MOC).
• The MOC is complex, difficult to measure but widely accepted by scientists.
Climate Change Workshop – BAESI – 5th Nov. 2011© Chevron 2011
Make your own THC!
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www.cleanet.org
www.wikipedia.org
Photo: Miriam Andres