Is Global Warming for Real?

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# Is Global Warming for Real? - PowerPoint PPT Presentation

Is Global Warming for Real?. J. C. Sprott Department of Physics University of Wisconsin - Madison Presented at the Chaos and Complex Systems Seminar In Madison, Wisconsin On January 17, 2006. Some Evidence. From Recent Seminars. Greenland Ice-core Data (C. S. Clay). 782,000 years.

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## Is Global Warming for Real?

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### Is Global Warming for Real?

J. C. Sprott

Department of Physics

Presented at the

Chaos and Complex Systems Seminar

On January 17, 2006

From Recent Seminars

Greenland Ice-core Data (C. S. Clay)

782,000 years

Lake Mendota Ice Cover (John Magnuson)

150 years

Prediction Methods
• Extrapolation methods
• Simple extrapolation
• Moving average
• Trends
• Linear methods
• Simple regression
• Autoregression
• All poles method
• Nonlinear methods
• Method of analogs
• Artificial neural network
Simple Extrapolation

3

2

1

Order = 0

Fit the last few points to a polynomial

Moving Average

Lags = 0

1

2

3

Average some number of previous points

Trends

2

1

Lags = 0

Follow the trend of some number of previous points

Linear Regression

2

3

Order = 0

1

Fit a polynomial to the entire data set

Autoregression

4

2

Order = 0

xt = a0 + a1xt-1 + a2xt-2 + …

All Poles Method

Poles = 0

2

4

1

Assume a sum of poles in the complex plane

Method of Analogs

Lags = 0

2

1

Find the closest similar previous sequence

Artificial Neural Network

D aij N bi

6 neurons

Lags = 3

tanh x

x

xt = xt-1 + Sbitanh[ai0 + ai1xt-1 + ai2xt-2 + ai3xt-3]

Artificial Neural Network

6 neurons

Lags = 3

xt = xt-1 + Sbitanh[ai0 + ai1xt-1 + ai2xt-2 + ai3xt-3]

Artificial Neural Network

6 neurons

Lags = 4

xt = xt-1 + Sbitanh[ai0 + ai1xt-1 + … + ai4xt-4]

Artificial Neural Network

6 neurons

Lags = 9

This year: 26 days

xt = xt-1 + Sbitanh[ai0 + ai1xt-1 + … + ai9xt-9]

Artificial Neural Network

6 neurons

Lags = 9

Chaotic?

450-year prediction

~30-70 days frozen

xt = xt-1 + Sbitanh[ai0 + ai1xt-1 + … + ai9xt-9]

Conclusion
• Eight predictors with ten or more values for the parameter give 80 very different predictions
• We could take an average of all the predictions
• Better yet, take the median of the predictions (half higher, half lower)
Median of 80 Predictions

Prediction for this season: 91 days (March 19th thaw)

Ice Core DataNeural Network Predictor

6 neurons

Lags = 9

782,000 years

xt = xt-1 + Sbitanh[ai0 + ai1xt-1 + … + ai9xt-9]

Closing Thoughts
• The Earth is getting warmer
• Human activity may not be the main cause
• Global warming may not be a bad thing
• Technological solutions may be available and relatively simple

sprott@physics.wisc.edu (contact me)

References