WILLIAM F RUDDIMAN EARTHS CLIMATE PAST and FUTURE

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WILLIAM F. RUDDIMAN EARTH’S CLIMATE PAST and FUTURE SECOND EDITION CHAPTER 10 Orbital-Scale Changes

WILLIAM F. RUDDIMAN EARTH’S CLIMATE PAST and FUTURE SECOND EDITION CHAPTER 10 Orbital-Scale Changes in Carbon Dioxide and Methane © 2008 W. H. Freeman and Company

What was the main driver of tectonic timescale climate change? • Atmospheric CO 2

What was the main driver of tectonic timescale climate change? • Atmospheric CO 2 levels • Did atmospheric CO 2 levels change with the glacial/interglacial cycles? – YES! • How do we know they changed? – From measurements of air bubbles trapped in Antarctic ice • Record now goes back over 600, 000 years

Activity: What does this figure tell you? When ice volume is low, CO 2

Activity: What does this figure tell you? When ice volume is low, CO 2 levels are at their maximum (280 -300 ppmv) and visa versa (minimum 180 -190 ppmv) CO 2 seems to change roughly in tandem with changes in ice volume What doesn’t this figure tell you? How CO 2 levels are related to changes in ice volume

Last full cycle showing error bars on measurements

Last full cycle showing error bars on measurements

Atmospheric CO 2 and the Ice Ages • Activity: Why might these be linked?

Atmospheric CO 2 and the Ice Ages • Activity: Why might these be linked? – Hint: what parts of the carbon cycle are affected by the ice ages? • Many possibilities: – CO 2 more soluble in colder ocean – Oceanic biologic activity fertilized by glacial dust – Changes in ocean p. H • Potential for positive feedback between CO 2 and ice volume (p. 265 -266) • Problem not solved!

Tracer to look at changes in distribution of C in global carbon reservoirs =

Tracer to look at changes in distribution of C in global carbon reservoirs = carbon isotopes

Which reservoir of C has the largest capacity to absorb extra C?

Which reservoir of C has the largest capacity to absorb extra C?

Evidence that the strength of Thermohaline Circulation has changed with the glacial cycles is

Evidence that the strength of Thermohaline Circulation has changed with the glacial cycles is clear How exactly this affects the CO 2 concentration of the atmosphere is not clear

What is the main source of Methane in nature? Given the insolation the ice-core

What is the main source of Methane in nature? Given the insolation the ice-core methane record is compared to on the right, which orbital cycle is driving the change in methane? What climatic phenomenon is driving the change in methane?

What drives what? The Paleoclimatologist’s puzzle According to the graph on the right, which

What drives what? The Paleoclimatologist’s puzzle According to the graph on the right, which comes first, changes in methane or changes in ice volume? Which came first, changes in CO 2 or ice volume? Based on these relationships, Ruddiman argues that CO 2 and methane can play a role in forcing ice volume changes and as a feedback mechanism for ice volume changes

precession tilt

precession tilt

WILLIAM F RUDDIMAN EARTHS CLIMATE PAST and FUTUREWILLIAM F RUDDIMAN EARTHS CLIMATE PAST and FUTURE
WILLIAM F RUDDIMAN EARTHS CLIMATE PAST and FUTUREWILLIAM F RUDDIMAN EARTHS CLIMATE PAST and FUTURE
Climate Data and Paleoclimate Proxies Ruddiman p 17Climate Data and Paleoclimate Proxies Ruddiman p 17
Past Tenses Simple Past Past continuous and PastPast Tenses Simple Past Past continuous and Past
PAST SIMPLE AND PAST CONTINUOUS PAST SIMPLE PastPAST SIMPLE AND PAST CONTINUOUS PAST SIMPLE Past
PAST TENSES PAST SIMPLE PAST CONTINUOUS AND PASTPAST TENSES PAST SIMPLE PAST CONTINUOUS AND PAST
PAST CONTINUOUS Past Continuous Past Simple Past ContinuousPAST CONTINUOUS Past Continuous Past Simple Past Continuous
PAST SIMPLE PAST CONTINUOUS PAST PERFECT PAST SIMPLEPAST SIMPLE PAST CONTINUOUS PAST PERFECT PAST SIMPLE
Past Tenses Past Simple Past Perfect Past ContinuousPast Tenses Past Simple Past Perfect Past Continuous
PAST SIMPLE Vs PAST CONTINUOUS PAST SIMPLE PASTPAST SIMPLE Vs PAST CONTINUOUS PAST SIMPLE PAST
Earths Climate System Factors Affecting Climate Earths AtmosphereEarths Climate System Factors Affecting Climate Earths Atmosphere
THE EARTHS CLIMATE SYSTEM Earths Climate System isTHE EARTHS CLIMATE SYSTEM Earths Climate System is
Components of Earths Climate Earths Climate System 4Components of Earths Climate Earths Climate System 4
Earths Climate Past Present and Future Concerns andEarths Climate Past Present and Future Concerns and
Earths Climate Past Present and Future Concerns andEarths Climate Past Present and Future Concerns and
Earths Climate Past Present and Future concerns andEarths Climate Past Present and Future concerns and
Earths Climate Past Present and Future Concerns andEarths Climate Past Present and Future Concerns and