Climate Change: What Do the Data Suggest?

Deborah Hughes HallettDepartment of Mathematics, University of Arizona

Harvard Kennedy School

Minneapolis Metrodome on December 12, 2010, after a 17 inch snowfall (luckily at 5 am)

http://sports.yahoo.com/nfl/blog/shutdown_corner/post/Amazing-before-and-after-pictures-of-the-Metrodo?urn=nfl-295249 and http://www.eurweb.com/wp-content/uploads/2010/12/metrodome_roof_collapse2010-med-wide.jpg

In 2009

At least 350,000 people stranded in Europe

London Dec 21, 2010

http://www.thedailybeast.com/blogs-and-stories/2010-12-21/heathrow-airport-shutdown-whats-the-real-cause/http://www.spiegel.de/fotostrecke/fotostrecke-62886-12.html

Europe’s airports, December 2010

London, UK, Dec 17

Frankfurt, Germany, Dec 21http://www.spiegel.de/fotostrecke/fotostrecke-62886-12.html http://www.bbc.co.uk/news/world-europe-12042213

Helsinki, Finland“The last time [the airport] was forced to close because of the weather was in 2003. That closure lasted for half an hour.” Dec 20, BBC

Boston, Winter 2011

Jan 21, 2011

Jan 27, 2011

http://www.boston.com/news/local/massachusetts/gallery/2010_2011_snowstormshttp://boston.cbslocal.com/2011/02/01/bostons-top-ten-snow-storms-of-all-time/

Snow Measurements at Logan Airport:1. February 17-18, 2003 27.5”2. February 6-7, 1978 27.1”3. February 24-27, 1969 26.3”4. March 31-April 1, 1997 25.4”5. January 22-23, 2005 22.5”6. January 20-21, 1978 21.4”7. March 3-5, 1960 19.8”8. February 16-17, 1958 19.4”9. February 8-10, 1994 18.7”10. January 7-8, 1996 18.2”10. December 20-22, 1975 18.2”10. December 26-27, 2010 18.2”

“Bundle Up, It’s Global Warming”Judah Cohen, December 25, 2010, NY Times

http://www.nytimes.com/2010/12/26/opinion/26cohen.html?_r=1

“All of this cold was met with perfect comic timing by the release of a World Meteorological Organization report showing that 2010 will probably be among the three warmest years on record, and 2001 through 2010 the warmest decade on record.”

On Dec 29, 2010: Climate Change Dispatch writes:“George Ifft, the American consul at Bergen, Norway, reported in 1922 the disappearance of icebergs….”

http://climatechangedispatch.com/home/8388-snow-blind

What Has Happened to Date:

• Temperatures rose 1-2 F during 1906-2005

• Sea level rise:

• In UK, increases of 2-4 inches since 1920

• In India, about 0.12 inches a year until 2000, since then, about 0.2 inches annually

• Carbon dioxide, CO2, in atmosphere increased from 316 ppm in 1959 to 386 ppm in 2008. (CO2 is believed by many to warm the planet.) From Tom Pfaff and http://www.epa.gov/climatechange/science/stateofknowledge.html and http://www.esrl.noaa.gov/gmd/ccgg/trends/index.html#mlo and http://www.cbsnews.com/stories/2010/03/24/world/main6329339.shtml and http://www.decc.gov.uk/en/content/cms/statistics/climate_change/data/data.aspx

Average Global Temperature

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Average Global Temperature over Time

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rage

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bal T

empe

ratu

re in

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gree

s C

elsi

us

http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt

Hockey Stick Graphintroduced in 1998 by Michael Mann

Intergovernmental Panel on Climate Change

A nearly yearlong effort by Attorney General Kenneth T. Cuccinelli II of Virginia to force the University of Virginia to turn over the documents of a prominent climatologist is headed to the state’s Supreme Court.John Collins Rudolf, New York Times March 12, 2011http://green.blogs.nytimes.com/2011/03/12/hearing-is-set-in-climate-fraud-case/

Sea Level Rise in UK Aberdeen in northeast and Newlyn in southwest

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Newlyn: Change in sea level(1916-2008)

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http://www.decc.gov.uk/en/content/cms/statistics/climate_change/data/data.aspx

100 mm is about 4 inches

Alaska“Future sea-level rise is an important issue related to the continuing buildup of atmospheric greenhouse gas concentrations.”

Alley, Richard B., Peter U. Clark, Philippe Huybrechts, and Ian Joughin (2005). "Ice-Sheet and Sea-Level Changes". Science 310

Pictures from www.globalwarmingart.com

Pictures from www.globalwarmingart.com

http://drake.marin.k12.ca.us/academics/rock/bears_files/polar-ice-caps-melting.jpghttp://www.dailymail.co.uk/news/worldnews/article-1213025/Melting-ice-cap-opens-Northeast-Passage-British-ships.html#ixzz1BS647LMq http://euobserver.com/9/26723

The Arctic

Sept 12, 2009“two merchant ships completed an historic shortcut over the once ice-bound top of the world.”

Carbon Dioxide Levels

http://cdiac.ornl.gov/new/keel_page.html

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Average Carbon Dioxide, Mauna Loa, Hawaii

Year

CO

2, p

arts

per

mill

ion

(ppm

)

Modeling Carbon Dioxide Levels

http://cdiac.ornl.gov/new/keel_page.html1940 1950 1960 1970 1980 1990 2000 2010 2020

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f(x) = 0.168371333645751 exp( 0.0038458538542033 x )R² = 0.9816011858082

Average Carbon Dioxide, Mauna Loa, Hawaii

YearCO

2, p

arts

per

mill

ion

(ppm

)

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f(x) = 1.32527414949762 x − 2281.78676409218R² = 0.974048486246997

Average Carbon Dioxide, Mauna Loa, Hawaii

Year

CO

2, p

arts

per

mill

ion

(ppm

)

Montreal Treaty and CFCs: Signed September 16, 1987; went into force January 1,

1989

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Chlorofluorocarbon (CFC) usage since Montreal Protocol

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CFC

s in

thou

sand

s of

tons

http://www.theozonehole.com/cfc.htm

Montreal Treaty and CFCs: Signed September 16, 1987; went into force January 1,

1989

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f(x) = 1156.58458391815 exp( − 0.187203344944523 x )R² = 0.961262167163412

Chlorofluorocarbon (CFC) usage since Montreal Protocol

Years since 1988

CFC

s in

thou

sand

s of

tons

http://www.theozonehole.com/cfc.htm

What are the Projected Growth Patterns?

• The carbon dioxide level increased by 1.3 ppm per year:Linear (if continued)

• The carbon dioxide level increased at a continuous rate of 0.4% per year (an annual increase of 0.4%):Exponential (if continued)

• The CFC usage decreased at a continuous rate of 18.7% per year (an annual decrease of 18.3%):Exponential (if continued)

Teaching Opportunities: Rates of Change and Projections

• Slope• Linear and exponential growth • Change and percent change• Rate of change and percent rate of change• The number e• Continuous and annual rate of change• Extrapolation and interpolation

Question: Are the changes significant?

NOVEMBER 30, 2009“The Climate Science Isn't Settled: Confident predictions of catastrophe are unwarranted .”

http://online.wsj.com/article/SB10001424052748703939404574567423917025400.html

"I think it's [concern about global warming] mainly just like little kids locking themselves in dark closets to see how much they can scare each other and themselves." http://www.sourcewatch.org/index.php?title=Richard_S._Lindzen

Richard Lindzen, Meteorologist, MITdoesn’t believe warming will be substantialhttp://www.sourcewatch.org/index.php?title=Richard_S._Lindzen http://www.heartland.org/events/NewYork09/

What is Predicted for the Future?

• Temperatures will rise about 3˚C (so 5-6˚F) over the next century, perhaps accelerating

• Polar ice caps and Greenland’s ice sheet will melt further

• Sea levels will rise about 1 meter over the next century, leading to flooding

• Carbon dioxide in atmosphere will increase, perhaps accelerating

From Intergovernmental Panel on Climate Change (IPCC) and http://www.esrl.noaa.gov/gmd/ccgg/trends/ and http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt

Why Are Ice Caps and Glaciers Melting?

• Average global temperature is rising – Past decade was warmest on record

• Why is the temperature rising?– Due to increase in greenhouse gasses in

atmosphere, especially carbon dioxide (CO2)• What causes the increase in CO2?

– This is where the controversy lies: • Man-made or natural?• Systematic trend or random fluctuations?• How much change will there be in the future?

What is the Evidence that CO2 Causes Temperature to Increase?

• Two types of evidence:– Data shows an association– A scientific mechanism

• Historical data shows temperature and CO2 tend to fluctuate together—but the relationship might not be causal

• There is a scientific mechanism explaining how an increase in CO2 causes temperature increases

• But some still doubt that the changes are large enough to be a problem

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Carbon Dioxide and Temperature

CO2

Temp

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bon

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xide

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rage

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pera

ture

, Cel

sius

What is the Effect of Increasing Carbon Dioxide in the Atmosphere?

Data http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt and http://cdiac.ornl.gov/new/keel_page.html

Other Ways of Looking at the Same Data

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CO2Temp

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xide

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rage

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ture

, Cel

sius

13.60 13.80 14.00 14.20 14.40 14.60 14.80 15.00300.00310.00320.00330.00340.00350.00360.00370.00380.00390.00

R² = 0.796178099274774

Carbon Dioxide and Temperature

Average temperature, Celsius

CO

2, p

pm

Data http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt and http://cdiac.ornl.gov/new/keel_page.html

Evidence of AssociationGraph of carbon dioxide (CO2) (green), temperature (blue), and dust concentration (red) measured from the Vostok, Antarctica, ice core …(Petit et al. 1999). The close correspondence between carbon dioxide changes and temperature changes is a characteristic feature of the recent ice ages …… the greenhouse gas feedbacks indicated here are believed to be responsible for most of the ice age climate change …… (Weaver et al. 1998). Higher dust levels are characteristic of cold, dry periods.

Teaching Opportunities: Carbon Dioxide and Average Temperature

• Graphs– Axes and scales

• Correlation– Range of values– Interpretation– Relation to causation

• Establishing causation– Scientific mechanism

Is the Temperature Rise Significant?

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f(x) = 0.00629365291197352 x + 1.78243287247104

Global Temperature since 1880

Year

Ave

rage

tem

pera

ture

in C⁰

Practical versus Statistical Significance

http://www.epa.gov/climatechange/effects/coastal/slrmaps_ne_mass.html

http://www.brophygen.com/

Sea levels will rise about 1 meter over the next century

Maps all from Sea Level Explorer, www.globalwarmingart.com

At Risk of Flooding from Sea Level Rise

Maldives Cabinet Meeting: President NasheedOct 17, 2009

Nepal Cabinet Meeting: Everest Base CampDec 4, 2009

http://www.npr.org/templates/story/story.php?storyId=121079253http://news.xinhuanet.com/english/2009-12/04/content_12588821.htmhttp://www.telegraph.co.uk/news/newstopics/howaboutthat/6356036/Maldives-government-holds-underwater-cabinet-meeting.html

Island sinks below waves

Wed 24 March 2010

http://www.guardian.co.uk/world/cif-green/2010/mar/24/india-bangladesh-sea-levelshttp://www.independent.co.uk/news/world/asia/rising-seas-claim-island-at-centre-of-30year-dispute-1927002.htmlhttp://www.cbsnews.com/stories/2010/03/24/world/main6329339.shtml

“For nearly 30 years, India and Bangladesh have argued over control of a tiny rock island in the Bay of Bengal. Now rising sea levels have resolved the dispute for them: the island's gone.”

Is the Temperature Rise Significant?

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f(x) = 0.00629365291197352 x + 1.78243287247104

Global Temperature since 1880

Year

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rage

tem

pera

ture

in C⁰

  CoefficientsStandard

Error t Stat P-valueLower 95%

Upper 95%

Intercept 1.7824 0.75215 2.37 0.019 0.2943 3.2706

Year 0.0063 0.00039 16.28 4.53E-33 0.0055 0.0071

Practical versus

Statistical Significance

Nenana Ice Classic, AlaskaPutting up tripod; March 6, 2011

April 23, 2010

http://www.nenanaakiceclassic.com/

Is the Ice Breaking Significantly Earlier?

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10

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f(x) = − 0.0741321388577828 x + 160.84568868981R² = 0.116266123606171

Nanana Ice Classic, AK

Year

Day

s si

nce

Apr

il 20

  CoefficientsStandard

Error t Stat P-value Lower 95% Upper 95%

Intercept 160.85 41.84 3.844 0.00022 77.74 243.95

Year -0.0741 0.0213 -3.479 0.00077 -0.116 -0.032

Teaching Opportunities: Temperature and Nenana Ice Classic

• Linear Regression• Interpolation and extrapolation• Interpretation of Slope• Confidence Intervals• P-value• Practical versus Statistical significance

“Warming increases the risk of civil war in Africa” M. Burke at al, Proceedings of the National Academy of Sciences, Dec 8, 2009

Panel regression of civil war incidence suggests that increases in temperature are more strongly related to an increase in civil wars than are changes in precipitation. (Previous studies suggested precipitation was important because if its role in agriculture.) The next slide shows the predicted change in civil wars till 2030.

Analysis in “Warming increases the risk of civil war in Africa” predicts a roughly 54% increase in civil war conflicts by 2030

Civil War: Somali Piracy 17 January 2011“Maritime piracy costs the global economy between $7 billion and $12 billion a year” http://af.reuters.com/article/topNews/idAFJOE70G09720110117

From NATO March 17. 2011At 0612 UTC / 17 MAR / a merchant vessel was reported under attack by 1 skiff from nearby suspected pirate mothership SINAR KUDUS.http://www.shipping.nato.int/CounterPir/copy_of_copy_of_SOMALIAPIR

http://news.blogs.cnn.com/2011/01/18/report-2010-was-worst-year-yet-for-piracy-on-high-seas/

Why Somalia? For 20 years, there’s been no governmenthttp://news.bbc.co.uk/2/hi/africa/8010061.stm

Teaching Opportunities: Climate Data and Civil Wars

• Descriptive statistics– Percentage vs. percentage point– Median, interquartile range– Box plots, error bars

• Regression tables– Linear functions of several variables

• Significance levels• Parameter estimates

– Standard errors• Bootstrap simulations

How Good Is the Data We Are Using?

• How can we check?• What biases might it have?

– Who collected it?– Why was it collected?– Compare with other data sets

http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif

TemperatureGlobal mean land-ocean temperature index, 1880 to present. The dotted black line is the annual mean and the solid red line is the five-year mean. Green bars show uncertainty estimates.

http://cait.wri.org/figures.php?page=/USToIntlGHGMap-Regions

US Greenhouse Gas Emissions Compared Internationally

Atmospheric Carbon Dioxide Carbon dioxide data from Mauna Loa started by David Keeling in March of 1958. The red line is the monthly mean values. The black line represents the same, after correction for the average seasonal cycle.

Dr. Pieter Tans, NOAA/ESRL (www.esrl.noaa.gov/gmd/ccgg/trends/)

Charles David Keeling,

Scripps Institution of Oceanography, San

Diego

At Mauna Loa, Hawaii, data on carbon dioxide has been collected since the 1950s with Dave Keeling’s “legendary exactitude”http://www.nytimes.com/2010/12/22/science/earth/22carbon.htmlhttp://green.blogs.nytimes.com/2010/12/21/does-the-keeling-curve-still-need-a-keeling/ http:// e-education.psu.edu

Ralph Keeling has produced a record of atmospheric levels of oxygen. … that is helping scientists understand what to expect from climate in the future.http://scrippsco2.ucsd.edu/home/index.php

In his colleagues’ view, he has established a record of painstaking measurement that nearly matches his father’s legendary exactitude.http://green.blogs.nytimes.com/2010/12/21/does-the-keeling-curve-still-need-a-keeling/#more-85421

Keeling Oxygen Curve

Teaching Opportunities: Carbon Dioxide Levels

• Curve fitting and prediction:– Linear, exponential, periodic– Long-term behavior of functions – Averages and smoothing

• Calculus:– Optimization– Least squares

Issues for Discussion

• How should we balance context and quantitative methods?

• How do we teach students to transfer a quantitative technique from one context to another?

• What is the best way to get students up to speed if they know little about the context?

• How can we include students with different political perspectives?