American Association of Petroleum Geologists
San Antonio, TX April 23, 20071
Modern Observations:Temperature Data and their Interpretation
Thomas C. PetersonNOAA’s National Climatic Data Center
Asheville, North Carolina
American Association of Petroleum Geologists
San Antonio, TX April 23, 20072
Outline
• How the climate is changing according to the data
• Efforts to insure the data base is robust• Post production quality assurance• Climate change attribution• Final comment
– Each of the above topics could be a full presentation on their own
American Association of Petroleum Geologists
San Antonio, TX April 23, 20073
How the climate is changing according to the data
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San Antonio, TX April 23, 20074
Global temperatures are rising
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San Antonio, TX April 23, 20075
US temperatures are generally similar
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San Antonio, TX April 23, 20076
Global warming is not uniform around the globe, e.g., the SE US
cooled
From IPCC 2007From IPCC, 2007
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San Antonio, TX April 23, 20077
More warming in the last few decades
From IPCC, 2007
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San Antonio, TX April 23, 20078
The recent observed climate change is beyond the bounds of
natural variability
From IPCC 2007
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San Antonio, TX April 23, 20079
The hottest summertime temperatures are increasing
From Peterson et al., 2008
North American average
American Association of Petroleum Geologists
San Antonio, TX April 23, 200710
Coldest winter temperatures are warming faster
From Peterson et al., 2008
North American average
American Association of Petroleum Geologists
San Antonio, TX April 23, 200711
Efforts to insure the data base is robust
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San Antonio, TX April 23, 200712
International data exchange
Source: Scott Woodruff
Note drop in dataduring WWII
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San Antonio, TX April 23, 200713
Quality control
• A wide variety of checks have been developed to identify erroneous data points.
From Peterson et al., 1998.
Bilma Niger
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San Antonio, TX April 23, 200714
Homogeneity adjustments – Sea Surface Temperature
example • Adjust historical data to make them equivalent to being observed by modern instruments at current station locations
SST measured before ~ 1941 are significantly coolerthan later SST, owing to change from using uninsulated buckets to a mixture of insulated buckets and engine coolant water intakes.
From UK Met Office Hadley Centre
From Smith and Reynolds, 2002
American Association of Petroleum Geologists
San Antonio, TX April 23, 200715
Homogeneity adjustments – Land air temperature station
example • Red is fully adjusted
• Black is only time of observation adjusted
• Top: temperatures
• Bottom: difference between Reno and mean of 10 nearest neighbors
Reno Nevada annual minimum temperature
From Menne et al., 2008
American Association of Petroleum Geologists
San Antonio, TX April 23, 200716
Spatial interpolation to fill in data sparse areas
• Prevents bias towards areas with good international data exchange
• NCDC’s approach uses Empirical Orthogonal Teleconnection Functions
American Association of Petroleum Geologists
San Antonio, TX April 23, 200717
Post production quality assurance
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San Antonio, TX April 23, 200718
Comparison with other data sets: They show the same thing
From Menne and Peterson, 2007, updated from IPCC 2007
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San Antonio, TX April 23, 200719
Comparison of land and oceans:
They show the same thing
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San Antonio, TX April 23, 200720
Comparison of urban and rural stations:
They show the same thing
From Peterson and Owen (2005) and IPCC 2007
American Association of Petroleum Geologists
San Antonio, TX April 23, 200721
Some stations have poor siting
Photographs from Daveyand Pielke, Sr. (2005)
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San Antonio, TX April 23, 200722
Comparison of stations with poor and good siting: They show the
same thing
From Peterson 2006Poorly cited stations in this example show less warming
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San Antonio, TX April 23, 200723
Doesn’t a station over concrete have a warm bias compared to a station over
grass?• For climate change purposes the relevant
questions are:– Does the bias change over time?– Can the changing bias be accounted for?
Photographs from Daveyand Pielke, Sr. (2005)
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San Antonio, TX April 23, 200724
A poorly sited station compared to its neighbors
• The station is 2º C warmer than neighbors
• But adjusted data’s trend agrees with its neighbors
Raw dataHomogeneity adjusted data
Marysville, CA, USHCN v2
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San Antonio, TX April 23, 200725
Comparison of homogeneous and homogeniety adjusted stations: They show
the same thing
From Peterson 2006
The stations with good siting onlyneeded two minor and offsettingtime of observation adjustments
American Association of Petroleum Geologists
San Antonio, TX April 23, 200726
Comparison of surface and upper air: Satellites and balloon data also show
warming.
From IPCC,2007
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San Antonio, TX April 23, 200727
Comparison with non-thermometer data
• Data from sources other than surface thermometers indicate that the world is warming
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San Antonio, TX April 23, 200728
Arctic sea-ice is shrinking
http://nsdl.org/resource/2200/20061002125757277T
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San Antonio, TX April 23, 200729
Antarctic sea ice is increasing
• So increases in Antarctic sea ice supports the data
• The data indicate cooling in the far southern oceans
American Association of Petroleum Geologists
San Antonio, TX April 23, 200730
Lakes and rivers are freezing later and thawing earlier
Figure 4.5
From IPCC,2007
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San Antonio, TX April 23, 200731
Glaciers are melting
From IPCC, 2007
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San Antonio, TX April 23, 200732
Sea level is rising
From IPCC, 2007
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San Antonio, TX April 23, 200733
Plants and animals are acting as if it is warming
• Plants are blooming 1-3 days/decade earlier– “Altered timing of spring events has been
reported for a broad multitude of species and locations” (IPCC 2007).
• Animals species are moving poleward– “Many studies of species abundances and
distributions corroborate predicted systematic shifts related to changes in climatic regimes” (IPCC 2007)
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San Antonio, TX April 23, 200734
Climate change attribution
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San Antonio, TX April 23, 200735
Detection and attribution
• The climate has warmed– Statistically significant change– Climate change has been detected
• But what has caused the detected change?– Climate change attribution
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San Antonio, TX April 23, 200736
• Each climate forcing has its own fingerprint of change in the climate.
From CCSP 1.1
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San Antonio, TX April 23, 200737
Models with and without human produced climate forcings reveal:
• “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations” (IPCC 2007).
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San Antonio, TX April 23, 200738
Final comment
• Stepping out into record hot weather, a friend who is an expert on climate change detection and attribution was asked if the high temperatures they were experiencing were due to global warming
• He responded:– You can’t attribute any one day’s
temperature to global warming– But unusually warm weather like that does
give us the privilege of experiencing the weather we are bequeathing our children and grandchildren
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San Antonio, TX April 23, 200739
The End
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San Antonio, TX April 23, 200740
But didn’t all the scientists predict global cooling back in
the 1970s?
7 cooling articles20 neutral articles
44 warming articles
Global cooling articles only 10% total climate change articles
From Peterson et al., 2008.
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San Antonio, TX April 23, 200741
Aren’t all the solutions painful?
• Efficiency can work wonders– Electricity use
per refrigerator has decreased to <30% of 1972 value
– Meanwhile, refrigerator size has increased
– And refrigerator price has decreased (in constant dollars).From:
Brown et al., 2005
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San Antonio, TX April 23, 200742
Selected References• Brown, M.A., F. Southworth, T. K. Stovall, 2005: Towards a Climate-Friendly Built
Environment. Pew Center on Global Climate Change, 91 pp.• Menne, M.J. and T.C. Peterson, 2007: Surface Temperature, in State of the Climate
in 2006. Arguez, A. ed., Bull. Amer. Meteor. Soc., 88, S11–S12.• Menne, M.J., C.N. Williams, Jr., and R.S. Vose, 2008: The United States Historical
Climatology Network serial monthly temperature data - Version 2. BAMS, submitted.
• Peterson, Thomas C., Russell S. Vose, Richard Schmoyer, and Vyachevslav Razuvaëv, 1998: GHCN quality control of monthly temperature data. International Journal of Climatology, 18, 1169-1179.
• Peterson, Thomas C. and Timothy W. Owen, 2005: Urban Heat Island Assessment: Metadata are Important. Journal of Climate, 18, 2637-2646.
• Peterson, Thomas C., 2006: Examination of Potential Biases in Air Temperature Caused by Poor Station Locations. Bulletin of the American Meteorological Society, 87, 1073-1080.
• Peterson, Thomas C., Xuebin Zhang, Manola Brunet India, Jorge Luis Vázquez Aguirre, 2008: Changes in North American extremes derived from daily weather data. Journal of Geophysical Research, in press.
• Peterson, Thomas C., Marjorie McGuirk, Tamara G. Houston, Andrew H. Horvitz and Michael F. Wehner, 2008: Climate Variability and Change with Implications for Transportation, National Research Council, in press.
• Peterson, Thomas C.,William M. Connolley and John Fleck, 2008: The myth of the 1970s global cooling scientific consensus. Bulletin of the American Meteorological Society, in press.
• Smith, T.M. and R.W. Reynolds, 2002: Bias corrections for historical sea surface temperatures based on marine air temperatures. J. Climate, 15 73-87.