Earths Climate: Past, Present and Future Fall Term - OLLI West: week - - PowerPoint PPT Presentation

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Earths Climate: Past, Present and Future Fall Term - OLLI West: week - - PowerPoint PPT Presentation

Mar 04, 2024 397 likes •1.04k views

Earths Climate: Past, Present and Future Fall Term - OLLI West: week 2, 9/23/2014 Paul Belanger Earth's past climate history 1. Earths deep past before the Cambrian (600 MaBP): hot and cold 2. Earths past: Cambrian onward: mostly

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Earth’s Climate: Past, Present and Future Fall Term - OLLI West: week 2, 9/23/2014 Paul Belanger Earth's past climate history

  • 1. Earth’s deep past before the Cambrian (600 MaBP): hot and cold
  • 2. Earth’s past: Cambrian onward: mostly hot-house Earth; 100s

parts per million (ppm)

  • 3. Climate trend in the Cenozoic – the last 65 million years; proxy

data from 3600ppm to <200 ppm.

  • 4. More recent past: 180-280 part per million; how do we know –

empirical data. Preview of next week’s field trip

  • 5. Today: 400 ppm and growing 2-3ppm/year
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REVIEW OF WEEK 1 ITEM

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  • Video I showed at end of week 1 class – what is climate:

– You tube link: https://www.youtube.com/watch?v=bjwmrg__ZVw

  • Video I didn’t show – /don’t have time – see syllabus:

– The climate system, feedbacks, cycles and self-regulation 1.6 – https://www.futurelearn.com/courses/climate-change-challenges- and-solutions/steps/3294/progress (7 mins) – an alternate: https://www.youtube.com/watch?v=lrPS2HiYVp8

– What factors determine Earth’s climate: – See IPCC-AR5 (2013-2014) tab on my web page: – And this link from AR4 (2007) http://denverclimatestudygroup.com/?page_id=63 – http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-1-1.html

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climate system - the inter-relationship and feedback of:

  • Atmosphere
  • Hydrosphere
  • Biosphere
  • Cryosphere
  • Lithosphere (weathering reduces CO2; volcanism increases it)
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10oC = (50oF) 7.8 cc 20oC = (68oF) 15 cc 30oC = (86oF) 27.7 cc 40oC = (104oF) 49.8 cc @ 30oC +1oC = 8% increase in vapor

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The CO2 greenhouse gas effect is concentrated in the polar regions ! ! !

The large H2O greenhouse effect is controlled by temperature – H2O saturation doubles with every 10°C Increase As a result It is concentrated in the lower atmosphere

  • f the tropics

CO2 is evenly distributed throughout the atmosphere

Particularly in the Arctic !

The Earth and its atmosphere

The most potent greenhouse gas is H2O - vapor

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WEEK 2

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  • 1. Earth’s deep past before the Cambrian (600 MaBP): hot

and cold

  • 2. Earth’s past: Cambrian onward: mostly hot-house

Earth; 100s parts per million (ppm)

  • 3. Climate trend in the Cenozoic – the last 65 million years;

proxy data from 3600ppm to <200 ppm.

  • 4. More recent past: 180-280 part per million; how do we

know – empirical data. Preview of next week’s field trip

  • 5. Today: 400 ppm and growing

Earth’s past climate

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Earth’s deep past and early atmosphere before the Cambrian (600 MaBP): hot and cold

  • Earth self regulates 2.1 -2.3 Tim Lenton video – 9 minute
  • verview
  • Article Link: BBC Nature

http://www.bbc.co.uk/nature/ancient_earth/Snowball_Eart h

  • You Tube – leaving for you to watch on your own:

https://www.youtube.com/results?search_query=snow+bal l+earth – various links

Earth’s past climate

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  • 1. Earth’s deep past before the Cambrian (600 MaBP): hot

and cold

  • 2. Earth’s past: Cambrian onward: mostly hot-house

Earth; 100s parts per million (ppm)

  • 3. Climate trend in the Cenozoic – the last 65 million years;

proxy data from 3600ppm to <200 ppm.

  • 4. More recent past: 180-280 part per million; how do we

know – empirical data. Preview of next week’s field trip

  • 5. Today: 400 ppm and growing

Earth’s past climate

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Climate Changes from Ocean Sediment Cores, since 5

  • Ma. Milankovitch Cycles

41K 100 K 3.0Ma 4.0Ma 2.0Ma 1.0Ma 5.0Ma When CO2 levels get below ~400-600 ppm Orbital parameters become more important than CO2

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  • 1. Earth’s deep past before the Cambrian (600 MaBP): hot

and cold

  • 2. Earth’s past: Cambrian onward: mostly hot-house

Earth; 100s parts per million (ppm)

  • 3. Climate trend in the Cenozoic – the last 65 million years;

proxy data from 3600ppm to <200 ppm.

  • 4. More recent past: 180-280 part per million; how do we

know – empirical data. Preview of next week’s field trip

  • 5. Today: 400 ppm and growing

Earth’s past climate

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Scientific History of Climate change – PROXY DATA

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Royer et al., 2003

Geologic cycles: Climate through the Phanerozoic: Carbon is the culprit

Alternating Greenhouse Earth / Ice-house Earth

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Cenozoic Deep Sea Climate Record

Zachos et al. 2008

hyperthermals

Opening of the Drake passage isolating Antarctica and further drop in CO2

Closing of Isthmus

  • f Panama

41k-100k & amplitude change: Increase in Antarctic ice

Azolla sequestering event

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Correlation of CO2 and temperature

  • ver last 65

million years

Beerling and Royer, Nature 2011

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Photosynthesis/Respiration CO2 + H20 ↔ CH2O + O2 Weathering/Precipitation CO2 + CaSiO3 ↔ CaCO3 + SiO2 Long-term Carbon Cycle: rocks

Two generalized reactions…

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Berner, 2001

Long-term carbon cycle: rocks

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50 million years ago (50 MYA) Earth was ice-free. Atmospheric CO2 amount was of the order of 1000 ppm 50 MYA. Atmospheric CO2 imbalance due to plate tectonics ~ 10-4 ppm per year.

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  • 1. Earth’s deep past before the Cambrian (600 MaBP): hot

and cold

  • 2. Earth’s past: Cambrian onward: mostly hot-house

Earth; 100s parts per million (ppm)

  • 3. Climate trend in the Cenozoic – the last 65 million years;

proxy data from 3600ppm to <200 ppm.

  • 4. More recent past: 180-280 part per million; how do we

know – empirical data. Preview of next week’s field trip

  • 5. Today: 400 ppm and growing

Earth’s past climate

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SLIDE 24

Climate Changes from Ocean Sediment Cores, since 5

  • Ma. Milankovitch Cycles

41K 100 K 3.0Ma 4.0Ma 2.0Ma 1.0Ma 5.0Ma When CO2 levels get below ~400-600 ppm Orbital parameters become more important than CO2

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SLIDE 25
  • 1. Earth’s deep past before the Cambrian (600 MaBP): hot

and cold

  • 2. Earth’s past: Cambrian onward: mostly hot-house

Earth; 100s parts per million (ppm)

  • 3. Climate trend in the Cenozoic – the last 65 million years;

proxy data from 3600ppm to <200 ppm.

  • 4. More recent past: 180-280 part per million; how do we

know – empirical data. Preview of next week’s field trip

  • 5. Today: 400 ppm and growing

Earth’s past climate

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  • SO –

WHAT CONTROLS CLIMATE

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SLIDE 27

Gerhard et al., 2001

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Rohling, et al., (PALAESENS Project mbrs), 2012 1o Forcings Solar Luminosity

  • Atm. Comp.

2o Forcings Continents (latitudes & elevations) Ocean circulation weathering CO2 3o Forcings Obliquity Precession Eccentricity CO2 /CH4

FEEDBACKS

4o Forcings Volcanic eruptions Sunspots Cycles El Nino/ La Nina Cloud Solar storms

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End of week 2 EXTRAS FOLLOW

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Paleocene/Eocene Thermal Maximum PETM

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Wikipedia

Proxy data: stable isotopes

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PETM - THE LAND RECORD

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Bighorn Basin

PETM interval in fluvial deposits with excellent alluvial paleosols - seen as color bands, which are soil horizons Found in Willwood Fm Reds, purples due to iron oxides in B horizons

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Paleosol Density

Pre-PETM PETM

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Bighorn Basin Climate

Plant fossils and isotopes show Mean Annual Temperature

  • f 20o to 25o C or 68

to 77o F Similar to Gulf Coast region today

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PROXY DATA-EXTRAS

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FROM CSI TO GSI: GEOLOGICAL SAMPLE INVESTIGATION

LET THE EVIDENCE SPEAK FOR ITSELF

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WE CALL THIS EVIDENCE “PROXY” DATA

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  • Strandlines/shorelines
  • Moraines
  • Till
  • Kettle lakes, etc.

SOME OF THE EARLIEST PROXY DATA WAS FROM TERRESTRIAL DEPOSITS

We may know what caused these today, but imagine back then?

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IT’S THE INTERPRETATION THAT’S NOT ALWAYS CORRECT Darwin observed ancient Alpine shorelines: interpreted as ocean shoreline Agassiz – later correctly interpreted as ice- dammed lake-shore strandlines/shoreline

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  • Jean Louis R.

Agassiz

  • “Father” of

Glaciology

  • 1807-1873
  • Paleontologist
  • Glaciologist
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Photographic proxy data/evidence

Ruddiman, 2008

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EARLY PROXY DATA: TREE RINGS

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Pollen & Lake core data

Ruddiman, 2008

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PROXY DATA: POLLEN DATA

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PROXY DATA: LEAVES

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Tree rings, corals, ice cores

Ruddiman, 2008

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PROXY DATA: ICE CORES

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TERRESTRIAL DATA North American: Wisconsin Illinoian Kansan Nebraskan European: Wurm Riss Mindel Gunz

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LATER EVIDENCE CAME FROM THE MARINE RECORD

NOT WITHOUT IT’S PROBLEMS, BUT MORE COMPLETE

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Cesare Emilani: Paleontologist, Chemist Father of Paleoceanography

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Other Paleoceanographers

Wally Broecker Thermal-haline “conveyor” belt of circulation

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Bill Ruddiman Nick Shackleton

Other Paleoceanographers

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Other Paleoceanographers

John Imbrie: CLIMAP

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PROXY DATA: CORE DATA

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PROXY DATA: BENTHIC FORAMS

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PROXY DATA: PLANKTONIC FORAMS

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Deep Sea Coring

Ruddiman, 2008