(pixabay) irrigation vs. global warming · 2020. 6. 29. · irrigation vs. global warming wim...
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||Department of hydrology and hydraulic engineering
Wim Thiery, Auke Visser, Erich Fischer, Annette Hirsch, Matthias Hauser, Edouard Davin, Quentin
Lejeune, Dave Lawrence & Sonia Seneviratne
20/05/2020 1
Irrigation vs. global warming
Wim Thiery
(Pixabay)
||Department of hydrology and hydraulic engineering Wim Thiery 20/05/2020
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 3
Present-day irrigation extent
(Adapted from Siebert et al., 2005 HESS)
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 4
T2m
(K)
(Thiery et al., 2017 JGR)
TXx
(K)
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 5
(Thiery et al., 2017 JGR)
(flickr.com)
Relation to global
warming?
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 7
20thC change in daytime temperature during hottest month (CRU)
(See also: van Oldenborgh et al., 2018
HESS for India + recent period)
||Department of hydrology and hydraulic engineering
Simulation set-up
▪ 4 x 5 member ensemble
▪ 1901-1930: CTL & IRR
▪ 1981-2010: CTL & IRR
▪ CESM1.2.2 - CLM4.0 (SP)
▪ HadIO SST & Sea ice fraction
▪ 0.9° x 1.25°
▪ Parameterized irrigation
20/05/2020Wim Thiery 8(adapted from Siebert et al., 2015 HESS)
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 9
Irrigation-induced cooling?
(Thiery et al., 2020 Nat. Comm.)
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 10
Correlation
vs.
causality
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 11
(Adapted from
Kumar et al., 2013 JGR;
Lejeune et al., 2018 Nature CC)
Present-dayEarly 20th Century
T + δTGHGT𝛿𝑇𝑡𝑜𝑡 = 𝛽0 + 𝛽1 × 𝛿𝑓𝑖𝑟𝑟 + 𝛽2 × 𝑙𝑎𝑡 + 𝛽3 × 𝑙𝑜𝑛 + 𝛽4 × 𝑒𝑙𝑒𝑣Big box:
𝛿𝑇𝑖𝑟𝑟 = 𝛽1 × 𝛿𝑓𝑖𝑟𝑟Center pixel:
T1,2 + δTGHGT1,2
T2,2 + δTGHG + δTirr
T2,2
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 12
Irrigation-induced cooling!
CRU TS v3.22
(Thiery et al., 2020 Nat. Comm.)
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 13
Irrigation-induced cooling!
CRU TS v4.02
(Thiery et al., 2020 Nat. Comm.)
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 14
Probability ratio (PR)
𝑃𝑅 =𝑃𝑛𝑒𝑤𝑃𝑟𝑒𝑓
Pnew: event probability in the new situation
Pref : event probability in the reference situation
(Fischer and Knutti, 2015 Nature CC)
=0.5
0.1= 5
||Department of hydrology and hydraulic engineering
PR
20/05/2020Wim Thiery 15
Hot extremes become
less likely
Hot extremes become
more likely
All forcings except irrigation Irrigation expansion
PR
All forcings
PR
(Thiery et al., 2020 Nat. Comm.)
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 16
Change in probability
Hot extremes
less likely
Hot extremes
more likely
TX percentiles
PR
(Thiery et al., 2020 Nat. Comm.)
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 17
~5 % of all land ~3 % of all land
TX percentiles
PR
TX percentiles
PR
TX percentiles
PR
(Thiery et al., 2020 Nat. Comm.)
||Department of hydrology and hydraulic engineering 20/05/2020Wim Thiery 18
0.79 – 1.29 Billion people less exposed to hot extremes (≠ heat stress)
Thanks! Questions?
20.04.2016Wim Thiery19(Pixabay)
@WimThiery