Climate Change, Fuels, and Wildfire

Transcription

1 Climate Change, Fuels, and Wildfire November 29, 211 Partners in Environmental Technology Technical Symposium & Workshop SERDP ESTCP Anthony Westerling Sierra Nevada Research Institute University of California, Merced Joint Fire Sciences California Energy Commission NOAA OGP USDA Forest Service

2 Report Documentation Page Form Approved OMB No Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 124, Arlington VA Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 29 NOV TITLE AND SUBTITLE Climate Change, Fuels, and Wildfire 2. REPORT TYPE 3. DATES COVERED to a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University of California, Merced,Sierra Nevada Research Institute,52 N. Lake Road,Merced,CA, PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 1. SPONSOR/MONITOR S ACRONYM(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited 11. SPONSOR/MONITOR S REPORT NUMBER(S) 13. SUPPLEMENTARY NOTES Presented at the Partners in Environmental Technology Technical Symposium & Workshop, 29 Nov? 1 Dec 211, Washington, DC. Sponsored by SERDP and ESTCP. U.S. Government or Federal Rights License 14. ABSTRACT Climate affects both fuel availability and flammability on multiple time scales, and the relative importance of availability versus flammability as limiting drivers of wildfire activity varies across ecosystem types. Climatic controls on fuel flammability during the peak fire season dominate in dense forests with characteristically infrequent, high severity fire, while the effects of antecedent moisture on the availability of fine surface fuels may also play a role in forests with more frequent, lower severity fire regimes. Changes in future temperatures and in precipitation amounts, form (rain versus snow) and timing can all potentially alter fuels, fire regimes, and emissions. We will describe the primary drivers of fire activity in very diverse ecosystems in California and the Northern Rockies, and summarize how climate change may affect these. In order to assess changes in wildfire and emissions, it is particularly important to use modeling methods that demonstrably capture extreme events, as well as to model at spatial resolutions that can capture topographic influences on temperature and precipitation. We demonstrate probabilistic statistical models that are designed to meet these requirements in California and Northern Rockies. We demonstrate methods that allow the estimate of fuels management on vulnerability to climate change in diverse ecosystems. Altered climate may drive changes in burned area and fire severity may in turn profoundly impact emissions from wildfire in some areas of the western US. We demonstrate the production of emissions scenarios for approximately 2 future climate and development scenarios in California, and discuss the important drivers of differences in emissions across a wide range of scenarios. 15. SUBJECT TERMS

3 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Same as Report (SAR) 18. NUMBER OF PAGES 28 19a. NAME OF RESPONSIBLE PERSON Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18

4 Role of Fire in the Carbon Cycle under Climate Change Technical Session No. 1A C CLIMATE CHANGE, FUELS, AND WILDFIRE PROFESSOR ANTHONY LEROY WESTERLING University of California, Merced 52 N. Lake Road Merced, CA (29) awesterling@ucmerced.edu limate affects both fuel availability and flammability on multiple time scales, and the relative importance of availability versus flammability as limiting drivers of wildfire activity varies across ecosystem types. Climatic controls on fuel flammability during the peak fire season dominate in dense forests with characteristically infrequent, high severity fire, while the effects of antecedent moisture on the availability of fine surface fuels may also play a role in forests with more frequent, lower severity fire regimes. Changes in future temperatures and in precipitation amounts, form (rain versus snow) and timing can all potentially alter fuels, fire regimes, and emissions. We will describe the primary drivers of fire activity in very diverse ecosystems in California and the Northern Rockies, and summarize how climate change may affect these. In order to assess changes in wildfire and emissions, it is particularly important to use modeling methods that demonstrably capture extreme events, as well as to model at spatial resolutions that can capture topographic influences on temperature and precipitation. We demonstrate probabilistic statistical models that are designed to meet these requirements in California and Northern Rockies. We demonstrate methods that allow the estimate of fuels management on vulnerability to climate change in diverse ecosystems. Altered climate may drive changes in burned area and fire severity may in turn profoundly impact emissions from wildfire in some areas of the western US. We demonstrate the production of emissions scenarios for approximately 2 future climate and development scenarios in California, and discuss the important drivers of differences in emissions across a wide range of scenarios. C-6

5 Since the mid-198s Large Forest Wildfires Have Increased ~3%

6 Since the mid-198s Large Forest Wildfires Have Increased ~3% Other Large Wildfires Have Not Changed Substantially

7 Grass/Shrub fires follow WET years Forests burn when they are DRY Preceding years Year of Fire

8 Grass/Shrub Fires and Temperature 1.{)- C") o- C") L{) - C\1 U) (].)... o- i.i C\1 1.{)- T""" - T""" I I I I I I I Correlation:.8

9 Forest Fires & Temperature Correlation:.7

10 Forest Fires & Timing of Spring Correlation:.56

11 Western US Forest Wildfires and Spring-Summer Temperature "<:ti- T""" Timing of Spring Snowmelt l{) l{)...--t""" >. ~ /J~ ~ - Late.~~ ~.. ~ El{) l{)e I\. \. c.,/. \ c ~l{) ". /~ -I /. 1 T"""...-- l{)~ - CJ) CJ) >.l{) l{)>. ~T""" Early T"""~ "1 1" >.

12 Western US Forest Wildfires and Spring-Summer Temperature ""<:tl-., l{),..._.,... >. ~ El{) c ~l{) -I CJ) >.l{) ~... "Oi Timing of Spring Snowmelt >.o ~ ".,... Fire Season Length 3 2 o~ C'?~ (]) >. - 1 >. ~.,..." 1: First Discovery 2: Last Discovery 3: Last Control ~~----~------~------~------~------~------~----~

13 Late Snowmelt Years Early Snowmelt Years , NPS, USFS & BIA Fires over 1 acres

14 1867 American River Understory Fire Regimes Fire suppression has increased amount and connectivity of fuels Unnatural increase in tree density Fire regime has changed Fires are less frequent and more severe Increased risk of severe fire 1993 American River Veblen and Lorenz 1991

15 Stand replacement Fire Regime 1916 Fire suppression has had little effect Tree densities changed little over last century 1986 Fire regime has not changed Infrequent, severe crown fires are natural and still dominate Veblen and Lorenz 1991

16 Study Area Fire Ignitions /" GYE 1/ - Water - Snow/Ice Englemann Spruce-Subalpine Fir D Whitebark Pine - Interior Douglas Fir D Aspen - Lodgepole Pine

17 I --' spring and summer temperature anomaly ( C) spring and summer temperature anomaly ( C)

18 ..., c u a C\J - - ' , a> ro -o :; ~ Q) ro-o,... - Q)-o 1 ro ~-o 2co - ro ro ogo ~~ ooo oo 3:U) cs:> ([]).,... ce, oo I - I I I I I summer precipitation (standard deviation)

19 Fire Modeling Fire Presence/Absence Conditional Fire Number Conditional Burned Area Logit Model Poisson Lognormal Generalized Pareto Temperature Precipitation Moisture Deficit Topography Location & Month Temperature Precipitation Moisture Deficit Topography Location & Month Moisture Deficit Grid/Month Grid/Month/Presence Grid/Month/Fire

20 Combined models: Burned Area ~.,... I,., ~C\1 cu.,.....c L()., co ro,., Q) ro "'C~ Q) c,., ::::J..Co I! year 1995

21 observed NCAR CCSM 3. CNRM CM 3. GFDLCM 2.1 N I c year 25 21

22 Northern Rockies mamjja T anomaly (Celsius) co.r::. C\J 1\ en ~ C\J u::: t5 ~ (!) ll c ~ '<t ~ ".2 C\J co z

23 A: NCAR CCSM 3. SRES A2 _!otai_g.y~ v~u_etet~d_a~'! :-,-.'\...-, _ J 9_81! QY!O QU!n d_a[e~ ~. : ,, '! ] : ~.... l,..' - 'i ~..... l l ~ -\t -. L i J\ f. A~Vb _.. ~ j '.. ~ ]l u &._ t'.--~. 1. ~.J,,,. 1 : '. r. '.. ~ r..... ' ' >.! -= :..._::. :... i _ ' ' 21 B: CNRM CM 3. SRES A2 _!otai_g,y~ v~u_etet~d_a!:_e'! _ J 9Jll! QY!O QU!n d_a[e~ _ j M 1 :'o, f.u \: l I ] i 1] '!, \ ' I ~ flj r. J ~ t... I.:.., '....,.. : z. ~... I.... I!:.:.. r r. - ;; :- (-"'"/\ -;\,/~;: - 1 i" h---f J/.: 'y'\ f':ai{~ ~ : :::: Observed Burned Area. ~. Simulated: Median,. Simulated: lnterquartile Range Simulated: Ran e C: GFDL CM 2.1 SRES A2 _!otai_g.y~ v~u.etet~d_a!:_e<! J 9_81! QY!O QU!n d_a[e~ - i1 ~ -~ - ~ /!_ (. :, - H r :-~ f.!.. L ~. ~ i, dr j' 1 '; ' 1, ; \I \! \ 1, ~, 11 J... r 1., \ " \, ' ' I ' ~ ' '! ~ l l... I..... I... I ~ I ',..!.. t. ~.. T '' ~. 1 " year

24 I I I I

25 simulation time period C ~ (/) a: <x: z Q) "' E Q) +-' ct:s E () ct:s. ) C ~ ~ a: z..;- "' U')..;- Q) "' ::::l +-' v -~..;- ct:s (')..;-..;- "' T""" C\1 ~...J LL CD U')..;-..;-..;- (')..; longitude <1 <2 <3 <6 <9 <12 >12 fire rotation (yr)

26 Figure 4-2. Change in California Annual Average Daily Mean Temperature Relative to A 1 HaOCM3 12 A 1 PCM - A2 HaOCM3 ~ 1 A2 G FDL2.1 Cl) C) c::: 8 A2 PCM cu ~ 8 1 HaOCM3 8 1 GFDL2.1 Cl) 6... :::::s -~ 4 8. E 2 Cl) I- 81 PCM ~ ~ Cl) C) 4.4 fij ~ 3.3 Cl)... :::::s f! Cl) a. E 1.1 Cl) I- Higher Warming Medium Warming Range Lower Warming Range ~------~------~------~------~------~--L Change in California annual mean temperature ( F and oc) by year from 1961 to 21 relative to average-? year running mean. HadCM3 = Hadley Climate Model version 3 PCM = Parallel Climate Model GFDL2. 1 = Geophysical Fluid Dynamics Laboratory model 2.1 A 1, A2, and 81 refer to global emission scenarios explained in Section 4. They are higher (A 1 ), medium-high (A2), and lower (B 1) emission scenarios.

27 NCAR PCM1 SRES A2 MIDMID thresh=1 285 CNRM CM3 SRES A2 MIDMID thresh=1 285 GFDL CM21 SRES A2 MIDMID thresh=1 285

28 Change in M e~n Expected B by Emissions S urned Area cenario ----r r , r-- D ----r-- g~ ~D I I ----1, , ,... Q ----1,.... L() I'- ) T""" T""" C\J T""" C\J T""" c::o <( c::o <( c::o L() C\J C\J L() L() CX) C\J C\J C\J C\J C\J C\J <( L() CX) C\J

29 25 TPM Wildfire Emissions Scenarios for California T T 2,..._ > T --.- C) T... I T ~ --.- T... T I- I T I T I I J.._...J.._...J.._ I I I I I I J. I I I J. I J J.._ I J z (f) z (f) z f-- (f) z f-- (f) f-- (f) f-- (f) ~ ::::) ~ ::::) ~ (f) ::::) ~ (f) ::::) (f) ::::) (f) ::::) _j _j _j _j _j z _j _j z _j z _j z _j ()_ ()_ ()_ ::::) ::::) ::::) ()_ ::::) SRES B1 SRES A2 SRES 81 SRES A2 SRES B1 SRES A2 N =

30 Average annual wildfire CO2 Emissions Historic Low Warming Moderate Warming