climate change what do the data suggest n.
Skip this Video
Loading SlideShow in 5 Seconds..
Climate Change: What Do the Data Suggest? PowerPoint Presentation
Download Presentation
Climate Change: What Do the Data Suggest?

Loading in 2 Seconds...

play fullscreen
1 / 48

Climate Change: What Do the Data Suggest? - PowerPoint PPT Presentation

  • Uploaded on

Climate Change: What Do the Data Suggest?. Deborah Hughes Hallett Department of Mathematics, University of Arizona Harvard Kennedy School. Minneapolis Metrodome on December 12, 2010, after a 17 inch snowfall (luckily at 5 am). In 2009.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

Climate Change: What Do the Data Suggest?

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
climate change what do the data suggest

Climate Change: What Do the Data Suggest?

Deborah Hughes Hallett

Department of Mathematics, University of Arizona

Harvard Kennedy School

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

In 2009 and

at least 350 000 people stranded in europe
At least 350,000 people stranded in Europe

London Dec 21, 2010

europe s airports december 2010
Europe’s airports, December 2010

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

London, UK, Dec 17

Frankfurt, Germany, Dec 21

boston winter 2011

Boston, Winter 2011

Jan 21, 2011

Jan 27, 2011

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

“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….”

what has happened to date
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 and and and

average global temperature
Average Global Temperature

hockey stick graph introduced in 1998 by michael mann
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, 2011

sea level rise in uk aberdeen in northeast and newlyn in southwest
Sea Level Rise in UK Aberdeen in northeast and Newlyn in southwest

100 mm is about 4 inches



“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


The Arctic

Sept 12, 2009

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

carbon dioxide levels
Carbon Dioxide Levels

modeling carbon dioxide levels
Modeling Carbon Dioxide Levels

what are the projected growth patterns
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
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?


Richard Lindzen, Meteorologist, MITdoesn’t believe warming will be substantial

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

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 and

why are ice caps and glaciers melting
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 co 2 causes temperature to increase
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
what is the effect of increasing carbon dioxide in the atmosphere
What is the Effect of Increasing Carbon Dioxide in the Atmosphere?

Data and

other ways of looking at the same data
Other Ways of Looking at the Same Data

Data and


Evidence of Association

Graph 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
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
Is the Temperature Rise Significant?

Practical versus Statistical Significance


Sea levels will rise about 1 meter over the next century


At Risk of Flooding from Sea Level Rise

Maps all from Sea Level Explorer,



Cabinet Meeting:

Everest Base Camp

Dec 4, 2009


Cabinet Meeting: President Nasheed

Oct 17, 2009


Island sinks below waves

  • Wed 24 March 2010

“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 significant1
Is the Temperature Rise Significant?

Practical versus Statistical Significance

nenana ice classic alaska

Nenana Ice Classic, Alaska

Putting up tripod; March 6, 2011

April 23, 2010

teaching opportunities temperature and nenana ice classic
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”


March 17. 2011

At 0612 UTC / 17 MAR / a merchant vessel was reported under attack by 1 skiff from nearby suspected pirate mothership SINAR KUDUS.

Why Somalia?

For 20 years, there’s been no government

teaching opportunities climate data and civil wars
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 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


Global 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.


US Greenhouse Gas Emissions Compared Internationally


Dr. Pieter Tans, NOAA/ESRL (

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.

charles david keeling scripps institution of oceanography san diego
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”



Keeling Oxygen Curve

Ralph Keeling has produced a record of atmospheric levels of oxygen. … that is helping scientists understand what to expect from climate in the future.

In his colleagues’ view, he has established a record of painstaking measurement that nearly matches his father’s legendary exactitude.

teaching opportunities carbon dioxide levels
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
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 weinclude students with different political perspectives?