Presented at the Global Warming Study Group January 13, 2009 By Dag Nummedal Colorado Energy Research Institute Colorado School of Mines, Golden, CO 80401.

Presented at the

Global Warming Study Group

January 13, 2009

By

Dag NummedalColorado Energy Research Institute

Colorado School of Mines, Golden, CO 80401

Geological and Man-Made Climate and Sea Level Changes

CERI

• Geologists: we understand a bit about the climate in the past• Climate scientists: understand something about earth-ocean- atmosphere interactions• Physicists: understand something about the interaction of molecules and radiation• Chemists: understand something about the fate of CO2, in oceans and on land

Of all disciplines, geologists should appreciate the causes, magnitudes, and effects of climate change the most and play a leadership role in making the lay public understand what is at stake in global warming. Yet, we are perceived by our science colleagues as “climate challenged”. Why?

Global Warming – the Ultimate(?) – Major – Multidisciplinary Challenge of Our Time

Jean Baptiste Joseph Fourier (mathematician) in 1827 recognized that gases in the atmosphere that absorb IR radiation could warm up the earth’s surface

Recognition of the Greenhouse Effect

Earth without atmosphere: 3 oF or -16 oCEarth with atmosphere (which absorbs and reemits IR): 15 °C (59 °F, 288 °K).

Svante Arrhenius (chemist) defined and estimated “Climate Sensitivity”, T2x.Data from S.P. Langley, who wanted to know the temperature of the moon.Arrhenius use Langley’s data to see how the intensity of the IR light from the moonvaried by the angle of moon (length of path through earth’s atmosphere) and humidity.Concluded that doubling the CO2 concentration lead to 4 to 6 oC warming. Today, the best estimate is about 2.5 to 4 oC warming.

In the 1860's, John Tyndall (scientist) noted: “Waves of heat speed from our earth through our atmosphere towards space. These waves dash in their passage against the atoms of oxygen and nitrogen, and against molecules of aqueous vapour. Thinly scattered as these latter are, we might naturally think of them mainly as barriers to the waves of heat”.

WikikpediaSolar irradiance: 680 W/m2

See site: earth’s energy budget: http://en.wikipedia.org/wiki/Earth's_energy_budget

Long wave radiation from earth

Conclusions - 1 Greenhouse effect – physics simple and well-understood. The greenhouse works. A good thing!

The Many Time Scales of Climate Change• Daily to several years: Weather – not Climate

• Century: the climate change the IPCC and people everywhere are worried about, because it affects the economy of society, and tracks man’s direct impact

• Centuries to millennia – Dansgaard-Oeschger cycles; Heinrich events

• 20 to 400 thousand years (perhaps more) – Milankovitch cycles in insolation due to earth’s orbital changes

• 100s of millions years – Pennsylvanian ‘ice house’ and Cretaceous ‘greenhouse’ due to plate tectonic cycles of continental assembly and break-up and vertical movements. Cycling of CO2 into and out of earth

Unique events: “Snowball earth” in late Proterozoic (and more?)Large volcanic eruptions (OAE-2 at C/T boundary)PETM – major heat spike due to?

Message: Don’t confuse the causes of climate change at one time scale with the drivers of change at another. Example: CO2 vs. temperature “leads and lags”.

Relative changes in oxygen isotope ratios can be interpreted as rough changes in climate. Quantitative conversion between this data and direct temperature changes is a complicated process subject to many systematic uncertainties, however it is estimated that each 1 part per thousand change in δ18O represents roughly a 1.5-2 °C change in tropical sea surface temperatures (Veizer et al. 2000).

Phanerozoic Climate Patterns

Conclusions - 2Greenhouse effect – physics simple and well-understood. The greenhouse works. A good thing!

Long-term (100 ma scale) climate change are due to CO2 imbalance between emissions rates and geological storage (weathering, ocean carbonates).

Cretaceous and Cenozoic Sea Level Histories

Authors:

Pitman, 1976Watts and Steckler, 1979Watts and Thorne, 1984Kominz, 1984Haq et al., 1986Gordon and Jurdy, 1986Miller et al., 2005Haq and Al-Qahtani, 2006Xu et al., 2006

Compiled by Muller et al., 2008

R. D. Muller et al., 2008

Age-Area Distribution of the Ocean Floor

140 Ma 100 Ma

50 Ma 0 Ma

70

60

50

40

30

4400

4600

4800

5000

140 120 100 80 60 40 20 0

All oceans

All oceans

Reconstruction age (Ma)(from Mller, et al., 2008)

Changes in Ocean Depth

From Muller et al., 2008

Wikipedia

Cenozoic Climate Record

Milankovitch Cycles

Wikipedia

Climate Changes from Ocean Sediment Cores, since 5 Ma. Milankovitch Cycles

Abreu and Nummedal, 2007

Seismically Defined Sequences – in Depth

Late Miocene Sequences in Kirmaky Valley,Baku, Azerbaijan

Outcrop Gamma Log at Kirmaky Valley

Insolation Index from 6 to 4 Ma

Berger and Loutre, 1992

Cycle Tuning, Kirmaky Suite

Conclusions - 3 Greenhouse effect – physics simple and well-understood. The greenhouse works. A good thing!

Long-term (100 ma scale) climate change are due to CO2 imbalance between emissions rates and geological storage (weathering, ocean carbonates).

Climate changes in the Milankovitch frequency band (20 ka to ~ 400,000 ka (or more?) are expressed in nearly all sedimentary systems on Earth. The 400,000 year cycles are particularly ‘robust’.

Milankovitch Cycles the Past 1 Million Years

Berger and Loutre, 1992

400,000 Year Climate Records

NOAA data base archives

Mann et al., 1999 – ‘hockey stick’ diagram for past 1000-yr temperature. Temperature and CO2 ‘correlative’ trends. Correlation does not prove causation – correct. CO2 should ‘lead’ temperature changes. In many cycles is does, but not always because of feed-back mechanisms due to role of vegetation.

Other papers revealed that a rapid rise in sea level, caused by the melting of land-based ice that began approximately 19,000 years ago, preceded the post-glacial rise in atmospheric CO2 concentration by about 3,000 years.  Then, when the CO2 finally began to rise, it had to race to make up the difference; but it still took it a couple more thousand years to catch up with the sea level rise.Explanation: emerging from the Ice age is a function of increasing solar insolation -an expression of the precessional (20-ky) Milankovitch cycle. This will cause temperature increase, more growth of plants, decay, methane production, oxidation to CO2, increased atmospheric CO2 and an amplification of temperature increase.

There are other data that show that during glacial inceptions of the past half million years, temperature always dropped before the air's CO2 concentration declined. “Clearly, therefore, changes in the air's CO2 content cannot be responsible for these major climate changes, for it would be a strange cause indeed that followed its effect!” CORRECT: nobody has argued that ice ages were driven by CO2 – they were driven by changes in solar insolation.

CO2 vs. Temperature Leads and Lags

Conclusions - 4 Greenhouse effect – physics simple and well-understood. The greenhouse works. A good thing!

Long-term (100 ma scale) climate change are due to CO2 imbalance between emissions rates and geological storage (weathering, ocean carbonates).

Climate changes in the Milankovitch frequency band (20 ka to ~ 400,000 ka (or more?) are expressed in nearly all sedimentary systems on Earth.

Both Milankovitch insolation cycles and feed-back mechanisms with vegetation drove Pleistocene-Holocene temperature patterns. Leads and lags are consistent with the physical causes.

Combination of causes – a series of catastrophes, one worse than the previous: Major volcanic induced global warming• The Siberian Traps eruptions were bad enough in their own right (huge CO2 burp)

• They occurred near coal beds and the continental shelf, they also triggered very large releases of carbon dioxide and methane (perhaps from hydrates)

•Most likely driven by massive degassing of methane hydrates to CH4, oxidized to CO2

• The oceans may have became so anoxic that anaerobic sulfur-reducing organisms dominated the chemistry of the oceans and caused massive emissions of toxic hydrogen sulfide

Unique Events 1 – Permian-Triassic

Extinction at251.4 Ma

% genera extinction

J. C. Zachos et al., Science 302, 1551 -1554 (2003)

Unique Events – Example 2:The PETM Climate Event

Plants preferentially ‘eat’ 12C. So, when 13C/12C goes down, there is a ‘burst’ ofCO2 much more than plants can absorb.The more ocean water is stored as ice on land, the heavier the remaining water.So, when 18O goes down, it is high sea level, little global ice, warm climate.Conclusion: 13C concentrations decay over a few 100,000s years. What about the present CO2 burst?

• Organic rich sedimentary rock formed in lake or marine environments• Commonly carbonate rich; most not true shale• Kerogen-rich, primarily algal and bacterial• Immature precursor to oil & gas• Produces oil upon heating

Colorado’sOil Shale a Productof the PETM?

Boak

Pica

Age (Ma)

48

49

50

51

52

53

54

14

13

12

11

10

9

8

7

6

5

4

3

2

1

Piceance Creek Seqs. (400k)

Greater Green River

48.8

49.6 Sixth Lane

y

Wilkins P

eak

TiptonGarden Gulch

Para

chut

e Cr

eek

Douglas Creek

51.3 Rife

51.8 Scheggs

Wasatch

49.8 Layered50 Main

50.4 Grey50.6 Boar

50.8 Firehole

Mbr.AgesGGRPC

Lake Type

Under Filled

Balanced Fill

Overfilled

HH T

TN

H – haliteN - nahcoliteT - trona

A

F or D

I

N

N

Luman

PETM event

13 Green River Sequences Represent

400 ka Milankovitch CyclesS N

Upper salt

Lower salt

Mahogany Zone

R-0

Sandstone

Sandstones

Oil Shale

R-2

R-1

R-3R-4

R-5R-6

R-7

Carbonates

Colors represent a total of 13 sequences

Bartov et al.

Conclusions - 5

Greenhouse effect – physics simple and well-understood. The greenhouse works. A good thing!

Long-term (100 ma scale) climate change are due to CO2 imbalance between emissions rates and geological storage (weathering, ocean carbonates).

Climate changes in the Milankovitch frequency band (20 ka to ~ 400,000 ka (or more?) are expressed in nearly all sedimentary systems on Earth.

Both Milankovitch insolation and feed-back mechanisms with vegetation drove Pleistocene Holocene temperature patterns. Leads and lags are consistent with the physical causes.

Unique events have long-lived consequences (‘forever’ in the case of the P/T extinction event, 100,000 s of years recovery from massive CO2 spike at the PETM. Natural events can be bad for life (including man).

Today’s Unique Event: Anthropogenic Global Warming

Today

CO2 for thepast 400 ky

NOAA web site archives & Peter Tans

The State of Affairs

Wikipedia

Distribution of Warming: Polar/Cold Regions

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

ice-shelf break up is not controlled simply by climate. A number of other atmospheric, oceanic and glaciological factors are involved. For example, the location and spacing of fractures on the ice shelf such as crevasses and rifts are very important too because they determine how strong or weak the ice shelf is”.

The study is important because ice shelf collapse contributes to global sea level rise, albeit indirectly.  “Ice shelves themselves do not contribute directly to sea level rise because they are floating on the ocean and they already displace the same volume of water. But when the ice shelves collapse the glaciers that feed them speed up and get thinner, so they supply more ice to the oceans,” Prof. Glasser explained.

Professor Glasser acknowledges that global warming had a major part to play in the collapse, but emphasises

that it is only one in a number of contributory factors, and despite the dramatic nature of the break-up in 2002, both observations by glaciologists and numerical modeling by other scientists at NASA and CPOM (Centre of Polar Observation and Modeling) had pointed to an ice shelf in distress for decades previously. “It's likely that melting from higher ocean temperatures, or even a gradual decline in the ice mass of the Peninsula over the centuries, was pushing the Larsen to the brink”,.

Neil Glasser, Aberystwyth UniversityTed Scambos, University of Colorado's National Snow and Ice Data Centre

Larsen Ice Shelf Collapse 2002

Regional heating of the Arctic following rapid sea ice loss events. Following such events, heating extends up to 1500km inland from the sea

Source: Steve Deyo, ©University Corporation of Atmospheric Research

An early arctic melt will cause additional heating, additional greenhouse gas emissions and additional sea level rise, over and above those foreseen by existing climate models

Future Arctic Temperature Trends

Permafrost extent in the northern hemisphere

Climate Safety, 2008 from UNEP

Carbon Content by SourceVolumes of total carbon content estimated in billion tonnes

Climatesafety.orgFirst Published in the United Kingdom 2008 by the Public Interest Research Centre. Sources: Schuur et al., UNEP, CDIAC

U.S. Energy Policy

• “We have only two modes—complacency and panic.”

• —James R. Schlesinger, the first energy secretary, in 1977, on the country's approach to energy

What to Do About It?

Reduce emissions and increase sinks for GHGs – fast, very fast!

Conclusions

• Greenhouse effect – physics simple and well-understood. The greenhouse works. A good thing!

• Long-term (100 ma scale) climate change are due to CO2 imbalance between emissions rates and geological storage (weathering, ocean carbonates).

• Climate changes in the Milankovitch frequency band (20 ka to ~ 400,000 ka (or more?) are expressed in nearly all sedimentary systems on Earth.

• Both Milankovitch insolation and feed-back mechanisms with vegetation drove Pleistocene Holocene temperature patterns. Leads and lags are consistent with the physical causes.

• Unique events have long-lived consequences (‘forever’ in the case of the P/T extinction event, 100,000 years recovery from massive CO2 spike at the PETM

• Decrease emissions, increase storage of CO2 - NOW