Overview of New Extreme Heat Projections for California
Guido Franco*, Susan Wilhelm**
* Team Lead, Environmental Area (EA) Energy Generation Research Office
Research Division California Energy Commission [email protected]
** Project Manager for the Energy Part of the Fourth Assessment [email protected]
Outline
• Probabilistic Projections for California Climate Zones: Regional variations and commonalities in temperature and precipitation
• Next-Generation Model Results (pending): What’s coming?
• Projected Regional High- and Low- Temperature Extremes
• Timing, Frequency, and Intensity of Heat Waves: Regionally Downscaled Projections as Represented by Cal-Adapt’s Extreme Heat Tool
2
- 4 0 2 4 - 4 0 2 4 - 6 - 2 2 6
~:~[]~'"0 ::[]~-•@ l[]SlerraNe@~•
- 0.5 ~ - 0.5 ~ -1 -1.0 - 1.0 -2
- 3 - 4 024 - 4 024 - 4 0 4
::[]San Joaq.@)•:"•• JI '"~'@ - 0.5 -0.4
-0.6 .__._ __ ___, -4 0 2 4 -4 0 4
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SoCal coast 1.5[j]soCal mlns 0 3~Anza-Borrego 1.0 1.0 0:2 0.5 0.5 0.1
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-1 .0 - 1.5 -0.3
-4 0 2 4 -4 0 2 4 -4 0 4
Probabilistic Projections for California Climate Zones
• “Probabilistic” climate projections for CA have been created using multiple global climate models and downscaling techniques
• Models predict warming throughout the state (rightward shift for all regions)
• Very wide range of uncertainty with regard to whether precipitation will increase or decrease (not certain what will happen) PRIOR GENERATION OF GLOBAL
and precipitation (mm/day, y axis) in DJF. Outer ellipse CLIMATE MODELS encloses 95% of the data; inner encloses 50%.
Joint distributions of change in temperature (deg C, x axis)
Pierce, D
.W., et al. , 2
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RCP 8.5 - ''Bus·ness as Usuall" RCP 4.5 - Climate polic scenario Black Li ne - Historica l
40 -t------r---r-----r--r---~------.-----,-------.---r-----r----,,-------r--------.-----,-----,'
1950 1975 2000 2025 2050 2075
Next-Generation Model Results Using LOCA
• Increased spatial Annual average temperature for grid cell near SMF resolution (important for resolving community-level impacts)
• After year 2005, the green and red areas show projections.
• Very little difference in envelopes of variability associated with mid- and high-emissions trajectories before 2050.
Source: Franco and Oliver using data provided by David Pierce (Scripps)
4
NorCal coast
24 26 28 30 32 deg- C
Central coasl
0 .9 9 ~ Oal:j 0 .75
0.5
0.25 ( o'bs 0,01 ~-- - --~
26 30 34 311 dsg-C
Historical Future
SoCal coast
0 .99
Otr.~ 0 .75
0.5 0 2 5
o~M 0.01
0.99
Orr.~ 0.75
0 .5 0 .25
0~5 0.01
0 .01
NorCal central
~ -----~ 32 36 40
deg-C
Sac/Cent va lley
~ - ~ ---~ 3 6 38 40 42 44
deg- C
San Joaq. valley
~ 36 38 40 42
deg- C
SoCal mtns
~;;~ gJ;~ 0.75 0.75 0~ Q 5
0.25 0 .25
o'bs o~5 0.01 ~-----~ 0.01 ~---,----~
32 34 36 311 4 0 dsg-C
32 36 40 deg- C
Northeast Cal
28 32 36 40 deg- C
Sierra Nevada ~;;J;V 0.75 0.5
0.25
o!M o.oi ~ -----~
28 30 32 34 36 dsg-C
Inland empire
34 38 42 46 deg- C
Anza-Borrego ~i;f 0.75 0.5
0.25
o!M 0.01 ~-----~
38 42 46 5 0 dsg-C
Heat Waves: Expect them to be Worse
For highest three-day average temperature:
• Temperatures get higher (illustrated as rightward shift of projected (blue) distribution relative to historical (red))
• Extreme high temperatures show disproportionate shift for inland areas, including Sierra Nevada, Inland Empire (shown as increasing distance between historical and projected
temperature for highs)
Pierce, D.W., et al. , 2013. Climate Dynamics, 40, 839-856. doi:10.1007/s00382-012-1337-9.
Figure: Cumulative distribution functions of the highest 3-day average temperature in the year. 5
♦---♦------------- ♦ ♦----- ...
----~~~~;;--
Historical Future
0.999 0.99
~~! 0.5
0.25 0~5 0.01
0.001
0.999 0.99
~~! 0.5
0.25 0~5 0.01
0.001
Sac/Cent valley
---t-
r -5 0 5 10
Tmin(C)
San Joaq. valley
- 5 0 5 10 Tmin (C)
Cold Snaps Persist
• Heating Degree Days* decreasing in the Central Valley, according to NOAA
• Recent research finds a trend of decreasing winter fog in the Central Valley (Baldocci and Waller 2014, Geophys Res. Letters)
– Clear nights can result in very low temperatures
• Even with warming trends, cold snaps would not disappear (2050 projections)
* Heating Degree Days are a measure of the degree and duration of cool weather
0
200
400
600
800
1000
1200
1400
1600
1950 1960 1970 1980 1990 2000 2010 2020
He
atin
g D
egr
ee
s D
ays
(oC
)
Year
Sacramento ValleyWinter MonthsSan Joaquin ValleyWinter Months
Data Source: NOAA
“ Winter fog is decreasing in the fruit growing region of the Central Valley of California “
2050
NASA
Figure: Cumulative Distribution Functions of January Daily Minimum Temperatures (Tmin) in Sacramento & San Joaquin Valleys. Note that low-end extremes are expected to persist in the face of climate change.
6
AVS
Gardenland, Sacramento, CA, USA
DAYS A BOVE 104.5°F
5 12 19 1961-19')0 2016-2046° 2046· 2076·
This chart displays a count of the number of days (along they
axis) that the selected area on map is projected to exceed the area's calculated Extreme Heat Threshold for each year under the
RCP 4.5 scenario.
RCP4.5 Etn1s.sions peak around 2040,
then dec:lme
RCPB 5
An eX1 -emc heat l::i def ned as day April 1hrough October w11e1e the max mum temper an.-. exceeds the 98th historic.a perceolIle of max mum
terr.pera1ures b1m!d on ob!IC'\'l!d daily temperatwe data between 1 96 1 1990
• N of extreme h t ya aYefaged over -Jl'.ren llme pe1i across all
higt,'9tted mod
Le.aHBI I Data: OSM. Map Tiles: Car1o0B, Georoding::
1900 1980 2000 2040 2060 2080
ss I 50 50
45 45
40 40
35 35
30 30
25 25
20 20
15 15
10 10
1960 1980 2000 2020 2040 2060 2080 21(0
11iifi1i'i llfitfl Wif11'■ lifi'fl=iflt liMili'ti liliiP:Hf:fl l~IMII■ 1ck emodel 1ghl ll Shaw a ll mode I
Projected Extreme Heat in Sacramento: LOCA Results for RCP 4.5 (mid-policy scenario, peak emissions ca. 2040)
Historical data Projected data Scale: up to 55 days/year
AV
Gardenland, Sacramento, CA, USA
DAYS ABOVE 104.5°F
5 14 28 1961 · 1990 2016 4 2046" 2046 · 2076·
This chart displays a count of the number of days (along they axis) that the selected area on map is projected to exceed the area's calculated Extreme Heat Threshold for each year under the
RCP 8.5 scenario.
RCP4.5 RCP 8.5 EmisS10ns continue to rise
strongly through 2050 and
plateau a-cuid 2100
An eKtreme ;ea1 day rs def oed as a day Apnl througt October where tne max Tlllm temperatwe en:ee1s the 8th historic.a per< l!l'1 c,f maxmum tel'!'4)eta"Mes based observ da temperature data betwffn 196 1990
•N..nbef fel('!reme'u>atdaysaveragedO'l'er ventimeperiodl'Cr01aall high ted model!!
LeaHe1 I Data: OSM., Map Ti les: Cal1008, Geo coding: Aapzen
1080 2040 2060 20B0 70 I 70
60 .. 50
I £
60
50
40 40
30 - Ob.served Data
30
20 20
10 10
t 1960 1980 2000 2020 2040 2060 2080 21
lliifiil·I llfV.fl Miii'IW lifiMI Jdl IMiili'~I liUil'li:+I IIIIHHlil ■~IMli■ ICk amodel i:iht 1t. Show aa models
Projected Extreme Heat in Sacramento: LOCA Results for RCP 8.5 (continued “BAU” growth at 2%/yr)
Historical data Projected data Scale: up to 70 days/year
TEMPERATURE: EXTREME HEAT TOOL
11516 9th street sacramento ABOUT THE TOOL DI SCLAIMER & UNCERTAINTY
Timin g of Extreme Heat Days by Year OPTIONS
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p
Rosevi lle 0
oFo
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Davis Elk Grove
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Stockton 0
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October
Sept
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\ . . July .. .
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June
I. lay • 11 6 - 12 1•F
• 111 · ll 6' F
106 · 11 l' F t:,prll
10 I · 106' F
1950 1960 1970 1980
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1990 1000 20 10 2010 2030 20 -10 2050 2060 2070
A.nnua l t1111e step from 1950 to 2099
• •1 .: •I •. . • I'. I i, I
: I I o • I
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2080 2090
Projected Extreme Heat in Sacramento: W i d e r season, higher extremes
Toward latter part of century, unprecedented extremes as high as 116 to 121 degrees F projected
Dramatically longer extreme heat season by century’s end.
Thank You! Extreme heat tool for LOCA results will be available soon on the beta-site of Cal-Adapt 2.0:
http://beta.cal-adapt.org/
Please send your comments, questions, and tell us how you are using the data:
DISCLAIMER A staff member of the California Energy Commission prepared this presentation. As such, it does not necessarily represent the views of the Energy Commission, its employees, or the State of California. The
Energy Commission, the State of California, its employees, contractors and subcontractors make no warrant, express or implied, and assume no legal liability for the information in this presentation; nor
does any party represent that the uses of this information will not infringe upon privately owned rights. This presentation has not been approved or disapproved by the Energy Commission nor has the
Commission passed upon the accuracy or adequacy of the information in this presentation.