Iowa Climate Statement 2014
Christopher J. Anderson
Research Assistant Professor, Department of Agronomy
Assistant Director, Climate Science Program
Iowa State University
Ames, IA 50011
23 October 2014
Climate Change in Iowa is different from Climate Change on TV
The pattern of change in extreme rainfall is a fingerprint of human
influence on climate change.
Source: Min et al (2011, Nature). Human contribution to more-intense precipitation extremes.
Spring and Summer Rainfall In Iowa (1893-2014)
Rare Spring-Summer
rainfall combinations
are no longer rare.
20
1893-1980
1981-2014
1893-1980 Average
Jul-Aug Precipita on (inches)
1893-1980: 7
2008-2014: 5
1-in-20-yr return in 1893-1980 has 1-in-4-yr return in 1981-2014
15
1981-2014 Average
Dry Spring
Wet Summer
Wet Spring
Wet Summer
2010
2014
10
2008
5
2012
0
Dry Spring
0 Dry Summer 5
2013
Wet Spring
Wet Summer
10
15
May-Jun Precipita on (inches)
20
Two human climate change fingerprints on temperature:
(1) Land has warmed more than ocean
(2) Northern latitude has warmed more than middle latitude
Source: Bindoff, N.L., P.A. Stott, K.M. AchutaRao, M.R. Allen, N. Gillett, D. Gutzler, K. Hansingo, G. Hegerl, Y. Hu, S. Jain, I.I. Mokhov, J. Overland, J. Perlwitz, R. Sebbari and X. Zhang, 2013:
Detection and Attribution of Climate Change: from Global to Regional. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report
of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge
University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 867–952, doi:10.1017/CBO9781107415324.022.
Summer heat wave
trend is determined by
source of air.
Iowa’s hottest summers
are dry tropical, moist
tropical, and moist
tropical+.
Warming of northern
latitude has affected dry
polar, dry moderate,
moist polar, moist
moderate, but not Iowa’s
hottest air masses.
Source: Union of Concerned Scientists, Heat in the Heartland: 60 years of warming in the Midwest (2012)
Source: Union of Concerned Scientists, Heat in the Heartland: 60 years of warming in the Midwest (2012)
Humidity increase causes more hot nights during summer.
Iowa City June-July-August Minimum Temperature
55
53
51
49
47
45
43
41
39
37
35
1890
1905
1920
1935
1950
1965
1980
1995
2010
In Iowa City, high summer night time temperature is more frequent. Ten of the top 15 years
have occurred since 1990.
Humidity increases causes more hot nights
during summer heat waves.
1900
1920
1940
1960
1980
2000
−15
−5 0
5
Minimum of 3-day Minimum
−25
Minimum of 3−day Average Minimum Temperature
Maximum of 3-day Minimum
68 70 72 74 76 78
Maximum of 3−day Average Minimum Temperature
Iowa City 3-day Minimum Temperature
1900
1920
1940
1960
1980
2000
Length of Growing Season is 10 days longer across the Midwest
In Iowa, corn is planted one week earlier than in the 1950s.
As climate changes there will be more wet springs
Iowa May-June Rainfall
330
Climate Projection
of Iowa
Ensemble
MeanMay-June Rainfall
310
290
270
250
230
210
190
170
150
1960
1970
1980
1990
2000
2010
2020
2030
2040
2050
A one-in-ten year wet spring during 1960-1999 becomes a two-in-five year wet spring during
2020-2059.
Data Source: Climate projections from Stoner et al. (2013)
As climate changes there will more hot summer nights
Number of July Nights with Temperature > 70F
1960-1999
Data Source: Climate Projections from Stoner et al. (2013)
2020-2059
As climate changes there will be more hot summer days
Number of July Days with Temperature > 95F
1960-1999
2020-2059
2013: an example of things to come
27#
July%August*Temperature*(C)*
26#
25#
2013
24#
23#
22#
21#
1960+1999#
20#
150#
175#
Data Source: Stoner et al. (2013)
200#
2020+2059#
225#
250#
May%June*Rainfall*(mm)*
275#
300#
325#
What might Iowa Educators do Next?
• Identify additional climate-health connections
• Develop monitoring and decision tools
• Produce Information Sheets similar to Union of Concerned
Scientists “Confronting Climate Change” series
Iowa Climate Statement 2014
Christopher J. Anderson
Research Assistant Professor, Department of Agronomy
Assistant Director, Climate Science Program
Iowa State University
Ames, IA 50011
23 October 2014
2013: an example of things to come
Iowa Seasonality of Warm Season Rainfall
Ensemble Mean
July-August Rainfall(mm)
400
375
1960-1999
350
2020-2059
325
300
275
2013
250
225
200
175
150
125
100
150
175
200
225
250
275
May-June Rainfall (mm)
300
325
350
Temperature trend can not be explained without
Human emissions of greenhouse gases
The pattern of change in extreme rainfall is a fingerprint of human
influence on climate change.
Source: Bindoff, N.L., P.A. Stott, K.M. AchutaRao, M.R. Allen, N. Gillett, D. Gutzler, K. Hansingo, G. Hegerl, Y. Hu, S. Jain, I.I. Mokhov, J. Overland, J. Perlwitz, R. Sebbari and X. Zhang, 2013: Detection and Attribution of Climate Change: from Global to Regional.
In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A.
Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 867–952, doi:10.1017/CBO9781107415324.022.
Ocean Has Absorbed 64% of Energy
added by Greenhouse Gas Increase
More complete measurements,
such as satellites since 1980, has
reduced substantially the
uncertainty in energy storage
estimates.
Source: climatechange2013.org
Des Moines June-July-August Air Masses
Average Maximum Temperature
Upward change since 1945
Downward change since 1945
Dry Tropical: 95OF, -1.0OF
Moist Tropical+: 94OF, +2.0OF
Moist Tropical: 88.5OF, +0.5OF
Dry Moderate: 84.5OF, -0.25OF
Moist Moderate: 84OF, +4.0OF
Dry Polar: 77.5OF, +2.5OF
Moist Polar: 76OF, +6.0OF
Source: Union of Concerned Scientists, Heat in the Heartland: 60 years of warming in the Midwest (2012)
1900
1920
1940
1960
1980
2000
Dots: Values for each year
Red Line: 90%-tile
Blue Line: 10%-tile
Black Line: 1981-2010 average
105
100
95
90
Maximum of 3−day Average Maximum Temperature
90
86
82
78
Maximum of 3−day Average Temperature
Supporting Slides for Historical Narrative
Maximum of 3-day Average and Max Temp
1900
1920
1940
1960
1980
2000