climate history of the earth

Climate history of the Earth

ProgrammeClimate Archives

Icecores

Climate Proxies

Oxygen isotopes

Deuterium

…

Milankovitch

Tectonics and Ocean Current

Climate Archives

Holds information of climate changes through earth’s history.

General idea: layering of matter

Types: SedimentsOcean coresLake coresIce coresCoralsTree RingsPollenHistorical

Climate Archives: Dating

Radiometric dating

Counting annual layers

Climate Archives: ResolutionDepends onSediment influx rateDepth and rate of mixing

Ice cores

Lake and Ocean cores

Climate Archives: ResolutionIce cores

Climate Archives: ResolutionLake and Ocean cores

Proxy

In statistics, a proxy variable is something that is probably not in itself of any great interest, but from which a variable of interest can be obtained. In order for this to be the case, the proxy variable must have a close correlation, not necessarily linear or positive, with the inferred value.

Climate proxies are devices that suggest the climate patterns of the past, even before those patterns were archived by humans. To produce the most precise results, systematic cross-verification between proxy indicators is necessary for accuracy in readings and record-keeping.

Ocean Sediments

Fossil remains of plants and animals.

Plankton. Four major groups:Foraminifera, sand-sized, CaCO3 (ul)Coccoliths , clay-sized, CaCO3 (ll)Diatoms, silt-sized, SiO2 (ur)Radiolaria, sand, sized, SiO2 (lr)

Ocean Sediments

Fossil remains of plants and animals.

Plankton. Four major groups:Foraminifera, CaCO3 (ul)Coccoliths , CaCO3 (ll)Diatoms, SiO2 (ur)Radiolaria, SiO2 (lr)

Ice Core Drilling

Location of Ice Cores

http://www.nicl-smo.sr.unh.edu/maps/world/world.html

Counting annual layering

Air trapped in glacial ice: sintering

Detection of annual layers

Blog

http://adventures-in-climate-change.com/drillingintothepast/

Maria Banks, Ph.D in geology and planetary science.

Ice core drilling in the Antarctica.

Blog: The WAIS Divide field site

Our field site is located on the West Antarctic Ice Sheet (WAIS). At this site, the ice thickness is 11,365 feet. The snow accumulation is estimated at 17 inches/year. This is considered high accumulation for Antarctica. The average temperature at the site is -24 degrees F. This site is a good area to study ice cores because the relatively high accumulation creates thicker layers. Although the depth of the ice and the layers at this location span only the past 100,000 years, their thickness provides high resolution data in comparison to areas with lower accumulation/thinner layers. Also, this field site is located near an ice divide. A divide is a high point on the ice sheet that marks a division where the ice begins to flow in two different directions. The ice near a divide experiences less movement than ice in other parts of the ice sheet and thus the layers are less distorted and easier to analyze.

Blog: Why do we Study Ice Cores?

The goals of the WAIS Divide Ice Core Project are to develop a highly accurate climate record extending back 100,000 years (climatology), to study the stability of the West Antarctic Ice Sheet (glaciology), and investigate bacteria contained in ice cores (cryobiology).Isotopes in the water can be used as a thermometer to measure the temperature when the snow fell. Also, analyzing the chemicals captured by the snow helps determine the age of each layer and gives insight into the amount of winter sea ice surrounding Antarctica. Trapped air bubbles contain greenhouse gases (carbon dioxide, methane) which tell us concentrations of these gases in the air during the past. The electrical conductivity of the ice reveals how much acid is in the snow. Examining the physical properties of the ice yields information about the ice sheet both past and present. Scientists analyze the ice grain orientation which can tell them about changes in the flow of the ice or any unexpected changes in ice movement. This in turn may reveal information about the topography beneath the ice. Bacteria, carried to Antarctica by winds, provide an understanding of whether the Earth’s climate was wet or dry during different periods in the past.

Blog: How much is an ice core worth?

If you average the overall cost of running the project over the amount of core we expect to drill, it is roughly estimated that an ice core 1 meter (~3 feet) in length is worth approximately $20,000 (and possibly much more). This does not including the costs of supporting the lab work and research that produces the science from this ice core. Lets think about the ice that we have been working with at WAIS Divide this season. We pack 4 meters of ice into each core box. There are 8 boxes loaded onto each skid and 4 skids fit on one air force pallet. Using our estimated value for an ice core and completing the math, each air force pallets contains about $2,560,000 worth of ice. So far a total of 12 air force pallets of ice have been packed and sent out this season (ice drilled last season and ice acquired this season) and several more skids are packed and ready to go!Going into the estimate of the worth of each ice core are the costs of drill operation, personnel, core transportation, the costs of running a remote field camp, plus many, many other related expenses. For example, it costs ~$5,000 per hour to fly a Hercules military cargo plane (the planes we use to transport the ice out of the field and to McMurdo Station). This comes to roughly $30,000 per round trip … and that’s just to get the ice to McMurdo Station, not even off the continent! One must also take into account the costs of running and supporting a remote field camp with food and supplies. I have heard that overall there are roughly 5 support staff for each scientist in the field. The ice we handle everyday is literally worth millions of dollars and required years of hard work from many different people in different roles to acquire. Unfortunately, one can’t just hand over $20,000 dollars and get themselves another duplicate ice core. For example, it took almost 5 seasons or 5 years to acquire an ice core from a depth of 2,000m (3 years to set up camp, the arch, and the drill and core processing equipment, and about 2 years of full time (24 hours a day) production drilling)!

Blog: The Daily life

The staff are limited to one 2-minute shower a week!

Blog: The Daily Life

And before they can take a shower, they have to shovel snow to the heater.

Blog: But they also have fun

Antarctic gear twister

Blog: But they also have fun

And mini-golf

Pictures!

http://www.travelblog.org/Antarctica/blog-35013.htm

Lou, Bella and Jay from the University of Wisconsin-Madison are ice core drilling on the Antarctica (in jan 2006).

Core handlingWAIS: Core is removed from drill by a machine

Core handling

Cooled to about -27C

Never warmer than -20C (this is where certain gasses start to leak)

Core handlers take over

http://blogs.nature.com/news/blog/2010/01/antarctica_2010_ice_core_drill.html

Core handling

Depth: 1586 m. Approximate age: 8200 years.

Ash layer from the eruption of a volcano (Mt. Takahe)

Sources of uncertainties

Timescale: +/- 1-2 years

Diffusion

Spatial

Proxies

How to:

Proxies

No direct measurements Indirect measurements by proxies Sensibilities to different variables Separation of variables

Using more proxies then variables Linear dependence (?) Linear combination

Proxies

Oxygen Isotopes Deuterium Carbon Isotopes

Terrigenous components Foram size Lysocline ...

Oxygen Isotopes

O-16 O-17 O-18

99,759% 0,037% 0,204%

Oxygen Isotopes

Oxygen Isotopes

18O= 18O16O

Sample

18O16O

Reference

−1×1000

Reference=SMOW

Oxygen Isotopes - Mechanisms

Evaporation of (light) water Precipitation of (heavier) water

However Snow is lighter

Sea currents and winds Biological activity

Is temperature dependent...

Oxygen Isotopes - SPECMAP

Oxygen Isotopes-Universality

Oxygen Isotopes - Atmosphere

δ18O is +2,35% in atmosphere compared to SMOW Due to Dole effect – Biology

Planktic more subject to temperature

Deuterium

H D H-3

99.985% 0.015% ≳ 0%

Mass (compared to H2O) HDO: +5,5% H2(18-O) +11%

Reduced mass (H-O bond) H – (18-O): x1.06 D – O: x2

Deuterium – A temperature proxy

Carbon Isotopes

C-12 C-13 C-14

98,9% 1,1% ≳ 0%

13C=

13C12C

Sample

13C12C

Reference

−1×1000

Reference=Pedee Belemnite PDB

Carbon Isotopes - Mechanisms

Primary biological proxy More life in warmer areas => Natural gradiant of δ13-C =>

Proxy of Currents

Carbon Isotopes

Other

Measure of atmosphere in Icecores CO2 – H2O – Methane …

Pollen Terrigenous Component Foram size Lysocline ...

Phase-problems

Results

Results

100.000 year cycle 41.000 year cycle 23.000 year cycle Narrow spectral peaks Sudden terminations ”Sawtooth” shape

BREAK!

Croll/Milankovitc Cycles

Insolation is the main reason for long-term climatic changes

Shift of eccentricity Shift of axial tilt Axial precession Apsidial precession

Eccentricity (95 – 125 – 400 ky)

Axial tilt (41 ky)

Axial precession (26 ky)

Apsidal precession (21 ky)

Problems with Milankovitch

100 ky problem 400 ky problem Stage 1 and 11 problems Unsplit peak problem Causality problem ...

Stage 1 and 11 problems

Causality problem

Devils Hole, Nevada Timing determined by U → Th decay

”Solutions”

Statistical fluctuations Resonance …

Orbital inclination

Orbital inclination

Shifts in orbital inclination

Shifts from ecliptica in 70ky

Shifts from invariable plane in 100ky

Interplanetary dust

Scattering of Sunlight Formation of clouds Destruction of Ozone

Catlayst Bromine

Formation of Noctilucent Clouds

Noctilucent Clouds

Orbital inclination

Solves some problems: Stage 1 and 11 100 ky Causality

However We need insolation to account for 41 ky and 23 ky No explanation to sudden terminations Uncertanty to how noctilucent clouds behave

Litterature

Wikipedia Ice Ages and Astronomical Causes, Data, Spectral

Analysis and Mechanisms

Richard A. Muller and Gordon J. MacDonald

Ice ages

No ice on earth

PermianOrdocianvi/SilurianLate-Precambrian Qvarternary

Marshak 2001

Climate though 3.900 million years

Glacial striationsFrom the Permian inSouth Africa

Marshak 2001

Permian glacier in Africa

Methods for mapping tectonic movements

• Paleomagnetic compasses in continental basalt ~ 500 million years.

• Paleomagnetic compasses in basaltic oceanic crust ~175 million years.

L.A. Lawver, I.W.D. Dalziel, L.M. Gahagan, K.M. Martin, and D. Campbell.PLATES 2002 Atlas of Plate Reconstructions (750 Ma to Present Day).2002, University of Texas Institute for Geophysics, August 19, 2002

Ruddiman 2001, table 05-01

Ruddiman 2001, fig 05-19, p.118

Spreading rate of oceanic crust

Collision of continents formation of mountain ranges upliftweathering use of CO2 through weathering of silicates

CaSiO3 + CO2 CaCO3 + SiO2

Continent-continent collision

kontinent-kontinent kollision

Uplift Weatering Hypothesis– Tectonic Control of Co2 removal

Ruddiman 2001, fig 05-23 top, p. 122

Ruddiman 2001, fig 05-26, p. 124

Ruddiman 2001, fig 04-07

Ruddiman 2001, table 05-03

Recent Climate

• Ocean Circulation

• Last deglaciation

Warm summer’s day in Tromsø, Norway – 70°N

Warm summer’s day in East Greenland – 70°N

Global Ocean Conveyor (Broecker 1992)

Marshak 2001Circulation ~1600 years

Marshak 2001

Ocean Surface Circulation

Ruddiman, fig 14-02

Melting of N American ice sheet

Ruddiman, fig 14-08

Direction of melt-water outflow

Ruddiman, fig 14-05

Fresh-water pulse

Geographical extend and timing

Ruddiman, fig 14-06

Marine and terrestrial evidence

Litterature

• L.A. Lawver, I.W.D. Dalziel, L.M. Gahagan, K.M. Martin, and D. Campbell.PLATES 2002 Atlas of Plate Reconstructions (750 Ma to Present Day).2002, University of Texas Institute for Geophysics, August 19, 2002

• Marshak, Stephen. (2001) Earth Portrait of a Planet. New York, NY: Norton & Company, Inc

• Ruddiman, W.F. 2007. Earth’s Climate. Past and Future (2nd edition). New York, NY: W.H. Freeman and Company, Inc.

• Ruddiman, W.F. 2001. Earth’s Climate. Past and Future (1st edition). New York, NY: W.H. Freeman and Company, Inc

climate history of the earth

Education

resolution ice cores

climate history

location of ice cores

ice divide

climate patterns

information of climate

rate of mixing ice cores

ice thickness