Earth System ScienceEarth System Science

Dan Lunt, Dan Lunt,

Prof. Paul Valdes, Prof. Tony PayneProf. Paul Valdes, Prof. Tony Payne

Big PictureBig Picture

How do these systems How do these systems work?work?

What are the key drivers?What are the key drivers?How do the different parts How do the different parts

interact?interact?How do we measure and How do we measure and

predict climate?predict climate?What will happen in the What will happen in the

near future?near future?What has happened in the What has happened in the

past?past?

Course aims and Course aims and objectivesobjectives

• Introduce the study of the “Earth System”

• Understand the processes important in influencing the Earth System

• Understand the inter-connectivity of the major components of the Earth system

• Develop an appreciation of the methods used for studying climate

• Understand how and why we use climate models to inform our understanding of the climate system

Lecture seriesLecture series

Lecture 1: Introduction. Lecture 1: Introduction. Lecture 2: Future modelling and the IPCC.Lecture 2: Future modelling and the IPCC. Lecture 3: Past Climate ChangesLecture 3: Past Climate Changes Lecture 4: GeoengineeringLecture 4: Geoengineering Lecture 5: AtmospheresLecture 5: Atmospheres Lecture 6: Energy balance modellingLecture 6: Energy balance modelling Lecture 7: Basics of General Circulation ModellingLecture 7: Basics of General Circulation Modelling Lecture 8: OceansLecture 8: Oceans Lecture 9: Ice sheet dynamics (1)Lecture 9: Ice sheet dynamics (1) Lecture 10: Ice sheet dynamics (2)Lecture 10: Ice sheet dynamics (2)

+ practical sessions+ practical sessions

AssessmentAssessment

Based on practicalsBased on practicals

Write a brief report (in the Write a brief report (in the style of a Nature paper) on style of a Nature paper) on your investigations with the your investigations with the climate model (e.g. a past or climate model (e.g. a past or future simulation).future simulation).

Text booksText books To help see the “overall” picture, you may wish to To help see the “overall” picture, you may wish to

look at:look at: IPCC Working Group 1: Summary for Policymakers IPCC Working Group 1: Summary for Policymakers IPCC Working Group 1: Technical SummaryIPCC Working Group 1: Technical Summary IPCC Working Group 1: Individual chaptersIPCC Working Group 1: Individual chapters

(All available at http://ipcc-wg1.ucar.edu/wg1/wg1-report.html)(All available at http://ipcc-wg1.ucar.edu/wg1/wg1-report.html) Plus: Plus:

McGuffie K. and Henderson-Sellers A., 2005. McGuffie K. and Henderson-Sellers A., 2005. A Climate Modelling Primer.A Climate Modelling Primer. 3rd Ed. 3rd Ed. Wiley.Wiley.

Barry R.G. and Chorley R.J , 2003. Barry R.G. and Chorley R.J , 2003. Atmosphere, weather and climate.Atmosphere, weather and climate. 8th 8th Ed. Routledge.Ed. Routledge.

Bigg G.R. , 1996.Bigg G.R. , 1996.The oceans and climate. The oceans and climate. 2nd Ed. Cambridge University 2nd Ed. Cambridge University Press.Press.

Benn D.I. and Evans D.J.A., 1998. Benn D.I. and Evans D.J.A., 1998. Glaciers and glaciation.Glaciers and glaciation. Hodder Arnold. Hodder Arnold. Kump L.R., Kasting J.F., Crane R.G., 2004. Kump L.R., Kasting J.F., Crane R.G., 2004. The Earth system: an The Earth system: an

introduction to Earth systems scienceintroduction to Earth systems science. 2nd Ed.Prentice Hall.. 2nd Ed.Prentice Hall. Ruddiman W.F., 2001. Ruddiman W.F., 2001. Earth’s climate : past and futureEarth’s climate : past and future. W.H. Freeman . W.H. Freeman

and Company.and Company. Holton, J.R.: An Introduction to Dynamic Meteorology. Academic Press. Holton, J.R.: An Introduction to Dynamic Meteorology. Academic Press.

44thth Ed. Ed. Peixoto & Oort “Peixoto & Oort “Physics of ClimatePhysics of Climate””

Media

Government

“Urgent action is needed to combat climate change”

“Above all, climate change is the greatest challenge facing this generation.”

“Internationally, we will work for an ambitious, fair and legally binding climate change agreement”

Atmospheric CO2

Oceans absorb approx. 25% of emissions, and land (plants) absorb a further 25%

Leaving 50% of emissions to increase atmosphere concentration

CO2 emissions

The Greenhouse Effect

Oldfield, p4

The Earth System

General Circulation Models (GCMs)

2001 2007

2007

2001

1995

1995

1990

1990

History of GCMs

Surface Temperature: observations

Surface Temperature: HadCM3

How good are GCMs?(1) temperature

Precipitation: observations

Precipitation: HadCM3

Seaice: observations vs models

How good are GCMs?(2) Precip and seaice

How good are GCMs?(3) El Nino

Radiative Forcing – anthropogenic component

Historical Forcing and response (century)

Historical Forcing and response (millenium)

Attribution (global)

Attribution (regional)

The future – climate sensitivity

"Prediction is very difficult, especially if it's about the future." --Nils Bohr, Nobel laureate in Physics

"Those who have knowledge, don't predict. Those who predict, don't have knowledge. " --Lao Tzu, 6th Century BC Chinese Poet

"This is the first age that's ever paid much attention to the future, which is a little ironic since we may not have one. " --Arthur C. Clarke

http://www.met.rdg.ac.uk/cag/forecasting/quotes.html

Predicting the Future

SRES (SRES (special report on emissions scenarios) storylines

SRES storylines

Economic growth rapid

Population peak 2050

Technological growth rapid

Capacity building

A1F1: fossil intensive

A1T: non-fossil energy

A1B: Balance

Economic shift - services/information

Population peak 2050

Technology -clean/efficient

Global solutions to sustainability/equity

Economic development regional - disparity

Population continues rising

Technological growth - slow, fragmented

Self reliance, heterogeneity

Economic development intermediate

Population continues rising slowly

Technological growth - diverse

Local and regional solutions to environment/equity

No Additional climate initiatives

SRES storylines summary

A1F1 BAD

B1 GOOD

From Jo House

SRES storylines summary

IPCC SRES

Radiance calibrated lights obtained from night satellite imagery. Situation in 1995/1996 (bottom panel) and illustrative simulation for the SRES A1 scenario's implied GDP growth for 2070 (top panel).

SRES storylines in more detail

IPCC TAR

SRES: Emissions

IPCC TAR synthesis report 2001

Also include emissions scenarios for other greenhouse gases and aerosols.

How to go from emissions to concentrations?

IPCC TAR

Need to consider the components of the carbon cycle important on these timescales – ocean, land, and human pertubations.

Petit et al, Nature, 399, 429-436, 1999.

How to go from emissions to concentrations?

However, we still don’t fully understand the Vostok CO2 curve!!

From Andy Ridgwell

CO2 concentration projections

IPCC TAR

IPCC use relatively simple models to give CO2 concentration scenarios…..

The IPCC Process - summary

Future Climate Predictions - global

Future Climate Predictions – regional(1) temperature

Future Climate Predictions – regional(2) Precipitation and cloud cover

[stippling – at least 80% agree on sign of change]

Future Climate Predictions – regional(3) Ocean circulation

Summary Summary Summary Summary The atmospheric composition has changed

over the last century.

The climatic consequences of these variations can be represented using numerical models.

These models do a relatively good job of the last century (millenium) compared to observations.

Climatic change over the last century is predominantly anthropogenic.

Future scenarios of atmospheric composition have been developed.

Some modelled consequences of these future changes are robust, others less so.