OLLI WEST: EARTH CLIMATE – WEEK 3

Paul E. Belanger, Ph.D.

FIELD TRIP: NATIONAL ICE CORE LAB

Tuesday September 30, 2014

SPECIAL THANKS TO OUR HOST(s):

•Richard Nunn and other personnel in the Ice Core Lab

FIELD TRIP: NATIONAL ICE CORE LAB

Tuesday September 30, 2014

OLLI WEST: EARTH CLIMATE – WEEK 3

DATA

Western Interior Paleontological Society

EMPIRICAL DATAACTUAL MEASUREMENTS:

ATMOSPHERIC COMPOSITION,

STABLE ISOTOPES, % CO3,

ASSEMBLAGE INFORMATION,

ETC.

EMPIRICAL DATA

•SOME OF THIS DATA YOU CAN’T DO MUCH WITH

•ONE NEEDS TO INTERPRET WHAT IT MEANS

THAT THEN MAKES IT “PROXY” DATA

“PROXY” DATADATA BY WHICH WE MAKE INTERPRETATIONS

EARLY PROXY DATA:

TREE RINGS

Interpretation: dry or wet periods of time

PROXY DATA: LEAVES

Interpretation: Climatic regime: tropical, boreal, etc.

Deep Sea Coring

Ruddiman, 2008

PROXY DATA:

CORE DATA

PROXY DATA:

BENTHIC

FORAMS

PROXY DATA:

PLANKTONIC

FORAMS

STABLE ISOTOPES OF OXYGEN

OXYGEN: 8 protons/8 neutrons At. Mass = 16

• Isotopes: variants in nature that have more or less neutrons than the norm (dominant)

• In the natural world the Standard Mean Ocean Water (SMOW) today contains 2 atoms of Oxygen that have 8 protons and 10 neutrons = mass 18 for every 1000 atoms of “normal” oxygen – mass 16.

• This is measured as the del (delta = difference) of that isotope to the norm: i.e. δO18 = 2 o/oo and measurements are in reference to SMOW

STABLE ISOTOPES OF OXYGEN

IN SEA WATER H2O

OXYGEN in sea water: in reference to SMOW

= positive in glacials (more ice)

= negative farther back in time (less ice)

PROBLEM: no fossil sea water; therefore we rely on measurements from CaCO3 from foram shells, etc. that are in equilibrium with sea water (i.e. proxy data)

ISOTOPIC FRACTIONATIONISOTOPIC FRACTIONATION

WHAT CAN INFLUENCE OXYGEN ISOTOPIC RATIOS IN CaCO3

11o: Ice Volume (salinity) – up to 2 : Ice Volume (salinity) – up to 2 oo//oo oo SMOW:SMOW:

- a result of preferentially evaporating H- a result of preferentially evaporating H221616O O

from the ocean and accumulating it as ice from the ocean and accumulating it as ice on land (up to 100m worth of the ocean on land (up to 100m worth of the ocean

water) – thus enriching the oceans in Hwater) – thus enriching the oceans in H221818OO

11o: Temperature = ~+0.25 : Temperature = ~+0.25 oo//oo oo per drop of a per drop of a ooCC

OXYGEN ISOTOPIC RATIO INFLUENCES IN CaCO3

Local Salinity: ocean / fresh water / Local Salinity: ocean / fresh water /

proximity to rivers, etc.proximity to rivers, etc.

Species habitat: where in the water Species habitat: where in the water column do they live (temp/salinity)column do they live (temp/salinity)

22o INFLUENCES: INFLUENCES:

Species fractionation: a poorly Species fractionation: a poorly understood processunderstood process

ICE CORE DATA

EMPIRICAL DATA: Gas bubbles = % CO2, % O2, %N2, etc.

• Compare: actual measurements you can compare to values today

PROXY DATA: δO18, δC13 , δH2 ,(deuterium), etc. from H2O and correlate it to CaCO3 from Ocean samples

• Interpret: e.g. δO18: ice volume, temperature, salinity

EMPIRICAL AND PROXY DATA

ICE CORES

Brook, 2008 Nature

Empirical

Interpreted

Wikipedia

Proxy data: stable isotopes

- SO – WHAT CONTROLS

CLIMATE

Gerhard et al., 2001

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

Milankovitchcycles

(forcing factors)

But it’s also CO2 and here’s the geologic proof:

CASE STUDIES:

1.The Paleocene-Eocene Thermal Maximum (PETM) whereby CO2 increased dramatically and climate warmed dramatically as well

2.The Azolla event whereby CO2 dimished dramatically – yet temperature didn’t at much – it’s still being studied

The PETM

PETM - THE LAND RECORD

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

Paleosol DensityPaleosol Density

Pre-PETM

PETM

Bighorn Basin Climate

Plant fossils and isotopes show Mean Annual Temperature of 20o

to 25o C or 68 to 77o F

Similar to Gulf Coast region today

The Azolla event

the massive decrease in

atmospheric CO2?

Bujak, pers. Comm.

UNPRECEDENTED DROP IN CO2

• Eocene: 800,000 years of sequestration of Azolla organic matter

• Slower rates of plate tectonics = lower recycling of carbonate = reduction of CO2 in atmosphere

So what caused the drop in

CO2 in the Eocene and since?

P/E World

No Polar Ice Caps

From Blakey (2007)

ARCTIC EVENTS PROXY DATA

Brinkhuis et al,, 2006

Moran et al., 2006

ACEX Azolla core

• >8 metre ACEX core with 90% Azolla

• Azolla occurs as laminated layers

• indicates Azolla deposited in situ

• bottom-water anoxia at ACEX site

Bujak, pers. Comm.

the massive decrease in

atmospheric CO2?

Bujak, pers. Comm.

UNPRECEDENTED DROP IN CO2

The longer record

THE PRESENT

So what’s going on today?

What’s going to happen in the short-term?

Today’s Unique Event: Anthropogenic Global Warming

Today

CO2 for thepast 400 ky

Pliocene levelsof 400ppm

1946 – 1950

svs.gsfc.nasa.gov

2002 - 2006Temperature

svs.gsfc.nasa.gov

Arctic Sea Ice Extent

If sea-ice continues to contract rapidly over the next several years, Arctic land warming and permafrost thaw are likely to accelerate.David Lawrence, NCAR

Satellite imagery of sea ice extent in September1979, and at a record low in September 2007. Source: NASA

WikipediaSolar irradiance: 342 W/m2

Expected levels of CO2 around 2100 for business as usual

I refer you to Jeff Masters PowerPoint or PDF entitled: Earth's Climate: Where are we at, and where are we headed (click here: PowerPoint-11Mb or PDF-4Mb)

6 slides follow

Correcting for El NiCorrecting for El Niñño and La Nio and La Niñña Influences a Influences

Shows the Global Warming Trend More Clearly Shows the Global Warming Trend More Clearly

How to Abuse Statistics: Choose a Short Time How to Abuse Statistics: Choose a Short Time

Interval and Ignore the Long-Term Trend Interval and Ignore the Long-Term Trend