Afghanistan: which indicators track drought impact?

afg-drought 2026-04-04 (endorsed): SEAS5 MAM + CDI (ASI, VHI, ERA5 snow/soil moisture) over 5 northern provinces. Main season used here: Mar–May (winter wheat, spring rains). Production target: Wheat (FAOSTAT, national, % from 2001–2024 trend).

Framework area

Indicator	r with production	R²	Leave-one-out R²	p	AUC, impact seasons	AUC, CERF-dated	AUC, EM-DAT
Temperature	-0.65	0.42	+0.30	0.001	0.72	0.70	0.72
Biomass (zFPARc)	+0.54	0.29	+0.17	0.006	0.62	0.75	0.59
FAO ASI	-0.78	0.60	+0.54	0.000	0.65	0.81	0.59
FAO mean VHI	+0.74	0.54	+0.46	0.000	0.64	0.80	0.60
Rainfall (CHIRPS/ASAP)	+0.65	0.42	+0.32	0.001	0.58	0.60	0.58
Rainfall (ERA5)	+0.72	0.52	+0.44	0.000	0.64	0.71	0.59
SPI-3	+0.73	0.53	+0.45	0.000	0.56	0.64	0.51
Water balance	+0.66	0.44	+0.33	0.000	0.60	0.78	0.52

Combination	R²	Leave-one-out R²	Coefficients (z per sd)
Temperature + Biomass (zFPARc)	0.54	+0.42	-11.37 (p 0.003), +7.93 (p 0.029)
Temperature + Rainfall (CHIRPS/ASAP)	0.51	+0.37	-8.56 (p 0.059), +8.48 (p 0.061)
Temperature + FAO ASI	0.64	+0.55	-5.47 (p 0.153), -13.28 (p 0.002)
Biomass (zFPARc) + Rainfall (CHIRPS/ASAP)	0.49	+0.35	+6.50 (p 0.105), +10.86 (p 0.010)
Temperature + Biomass (zFPARc) + Rainfall (CHIRPS/ASAP)	0.57	+0.41	-8.30 (p 0.056), +6.24 (p 0.098), +5.67 (p 0.213)
Temperature + FAO mean VHI	0.59	+0.47	-6.46 (p 0.113), +11.78 (p 0.007)

Hot vs cool, low vs high biomass (median splits)

Quadrant	Seasons	Mean production anomaly	Impact-season rate	Seasons
hot / low biomass	7	-23.5%	43%	2001, 2004, 2006, 2008, 2011, 2021, 2022
hot / high biomass	5	+3.3%	20%	2002, 2007, 2010, 2016, 2023
cool / low biomass	5	+6.1%	20%	2012, 2014, 2017, 2018, 2024
cool / high biomass	7	+16.1%	14%	2003, 2005, 2009, 2013, 2015, 2019, 2020

Impact seasons (6): 2006, 2008, 2010, 2018, 2020, 2021.

National mean of ASAP units

Indicator	r with production	R²	Leave-one-out R²	p	AUC, impact seasons	AUC, CERF-dated	AUC, EM-DAT
Temperature	-0.70	0.50	+0.38	0.000	0.72	0.75	0.73
Biomass (zFPARc)	+0.08	0.01	-0.17	0.709	0.34	0.43	0.32
FAO ASI	-0.78	0.61	+0.54	0.000	0.63	0.75	0.61
FAO mean VHI	+0.76	0.58	+0.51	0.000	0.60	0.75	0.59
Rainfall (CHIRPS/ASAP)	+0.62	0.38	+0.28	0.001	0.56	0.51	0.62
Rainfall (ERA5)	+0.67	0.45	+0.34	0.000	0.62	0.62	0.60
SPI-3	+0.73	0.53	+0.45	0.000	0.66	0.60	0.65
Water balance	+0.68	0.47	+0.38	0.000	0.61	0.68	0.55

Combination	R²	Leave-one-out R²	Coefficients (z per sd)
Temperature + Biomass (zFPARc)	0.63	+0.50	-18.28 (p 0.000), +8.39 (p 0.013)
Temperature + Rainfall (CHIRPS/ASAP)	0.54	+0.39	-11.40 (p 0.015), +5.73 (p 0.198)
Temperature + FAO ASI	0.68	+0.57	-7.27 (p 0.053), -12.13 (p 0.003)
Biomass (zFPARc) + Rainfall (CHIRPS/ASAP)	0.39	+0.20	+2.31 (p 0.537), +13.43 (p 0.001)
Temperature + Biomass (zFPARc) + Rainfall (CHIRPS/ASAP)	0.64	+0.44	-16.06 (p 0.002), +7.71 (p 0.028), +2.95 (p 0.478)
Temperature + FAO mean VHI	0.65	+0.52	-7.38 (p 0.070), +11.43 (p 0.007)

Hot vs cool, low vs high biomass (median splits)

Quadrant	Seasons	Mean production anomaly	Impact-season rate	Seasons
hot / low biomass	6	-22.2%	50%	2001, 2008, 2011, 2017, 2018, 2021
hot / high biomass	6	-5.2%	33%	2002, 2004, 2006, 2007, 2010, 2022
cool / low biomass	6	+15.1%	0%	2003, 2005, 2012, 2014, 2019, 2024
cool / high biomass	6	+11.5%	17%	2009, 2013, 2015, 2016, 2020, 2023

Impact seasons (6): 2006, 2008, 2010, 2018, 2020, 2021.

How impact records were dated to seasons

Record	Period	Season	Rule
CERF 2006 Rapid Response $19.5M	2005-11-01 → 2006-05-28	2006	overlap
CERF 2006 Rapid Response $12.8M	2005-11-01 → 2006-05-28	2006	overlap
CERF 2008 Underfunded Emergencies $4.6M (undated)	2008-01-01 →	2007	undated: last-season-before-impact
CERF 2008 Rapid Response $8.0M (undated)	2008-01-01 →	2007	undated: last-season-before-impact
CERF 2010 Underfunded Emergencies $11.0M (undated)	2010-01-01 →	2009	undated: last-season-before-impact
CERF 2018 Rapid Response $11.9M	2017-10-01 → 2018-05-28	2018	overlap
CERF 2021 Rapid Response $15.0M	2020-10-01 → 2021-05-28	2021	overlap
CERF 2025 Rapid Response $6.7M	2024-10-01 → 2025-05-28	2025	overlap
EM-DAT 2000-9186-AFG (2580000 affected)	2000-05-01 → 2002-12-28	2000	last-season-before-impact
EM-DAT 2006-9570-AFG (1900000 affected)	2006-07-01 → 2006-12-28	2006	last-season-before-impact
EM-DAT 2008-9475-AFG (280000 affected)	2008-10-01 → 2008-10-28	2008	last-season-before-impact
EM-DAT 2011-9312-AFG (1750000 affected)	2011-01-01 → 2011-08-28	2010	last-season-before-impact
EM-DAT 2018-9278-AFG (13500000 affected)	2018-04-01 → 2019-07-28	2018	last-season-before-impact
EM-DAT 2021-9116-AFG (11000000 affected)	2021-01-01 → 2023-05-28	2020	last-season-before-impact

Season table

	t_spring_aoi	t_dt_spring_aoi	rain_spring_aoi	wsi_spring_aoi	spi_spring_aoi	z_spring_aoi	z_dt_spring_aoi	t_spring_nat	t_dt_spring_nat	rain_spring_nat	wsi_spring_nat	spi_spring_nat	z_spring_nat	z_dt_spring_nat	era5_nat	era5_aoi	asi_nat	asi_aoi	mvhi_nat	mvhi_aoi	prod_anom	impact	impact_cerf	impact_emdat	impact_plus_undated
year
2001	17.11	3.11	6.04	57.16	-1.65	-1.07	-1.25	14.02	2.36	9.32	63.71	-1.14	-0.70	-0.34	0.80	0.71	80.59	92.54	0.26	0.22	-48.74	0	0	0	0
2002	14.91	0.81	17.51	82.30	0.33	0.71	0.55	13.27	1.51	15.07	74.85	0.15	-0.21	0.12	1.39	1.93	15.62	0.92	0.50	0.57	-16.06	0	0	0	0
2003	12.59	-1.61	20.56	85.57	1.10	0.52	0.37	11.36	-0.49	19.89	77.41	0.72	-0.32	-0.02	1.67	2.35	3.88	0.07	0.60	0.68	5.97	0	0	0	0
2004	14.94	0.64	8.82	65.74	-0.95	0.20	0.07	14.25	2.31	6.72	56.79	-1.67	-0.07	0.20	0.97	1.31	32.67	37.27	0.40	0.37	-29.05	0	0	0	0
2005	14.28	-0.12	14.48	71.93	0.08	0.21	0.09	11.05	-0.98	16.47	75.82	0.16	-0.58	-0.34	1.94	1.80	0.79	0.82	0.55	0.54	23.56	0	0	0	0
2006	15.98	1.48	9.37	71.32	-0.27	-0.09	-0.19	13.77	1.64	9.96	68.68	-0.38	0.07	0.28	0.99	1.15	38.79	31.89	0.37	0.37	-4.92	1	1	1	1
2007	15.24	0.64	17.69	77.24	0.78	0.36	0.27	12.80	0.58	19.61	71.78	0.86	-0.02	0.16	1.51	1.58	42.47	34.14	0.37	0.39	23.83	0	0	0	1
2008	17.19	2.49	6.61	57.61	-1.92	-1.30	-1.37	14.07	1.74	10.19	61.60	-1.26	-0.63	-0.48	0.95	0.89	82.18	96.23	0.22	0.16	-29.21	1	0	1	1
2009	14.27	-0.52	26.92	89.06	1.47	0.65	0.60	11.75	-0.67	21.24	82.30	0.76	-0.02	0.10	1.94	2.67	0.63	0.63	0.69	0.69	33.63	0	0	0	1
2010	16.04	1.15	13.93	78.63	0.56	0.88	0.84	14.06	1.55	13.41	69.16	0.06	0.62	0.71	1.39	1.78	5.06	0.63	0.57	0.57	16.99	1	0	1	1
2011	15.52	0.52	9.70	63.14	-0.34	-1.14	-1.17	13.12	0.51	10.40	66.41	-0.15	-0.56	-0.50	1.05	0.98	48.65	60.12	0.35	0.30	-14.41	0	0	0	0
2012	14.06	-1.03	14.95	75.56	0.02	-0.35	-0.37	11.14	-1.56	13.99	74.00	-0.20	-0.69	-0.66	1.45	1.84	9.86	7.59	0.51	0.50	24.92	0	0	0	0
2013	14.36	-0.83	13.26	71.50	0.03	0.56	0.56	12.00	-0.80	15.93	76.89	0.54	0.19	0.19	1.41	1.56	3.41	5.19	0.58	0.55	25.26	0	0	0	0
2014	14.26	-1.04	18.87	72.09	0.47	-0.57	-0.55	11.34	-1.55	23.99	80.03	0.68	-0.49	-0.52	2.18	2.32	8.31	14.99	0.54	0.46	27.53	0	0	0	0
2015	14.61	-0.78	14.95	73.11	0.75	0.49	0.52	12.29	-0.70	14.48	75.41	0.42	0.13	0.07	1.54	1.66	3.22	1.92	0.55	0.53	8.79	0	0	0	0
2016	15.98	0.49	17.94	71.13	0.08	0.86	0.91	13.38	0.30	22.19	76.32	0.43	0.83	0.74	2.08	2.20	2.66	3.03	0.57	0.56	4.01	0	0	0	0
2017	15.48	-0.11	11.68	73.18	0.54	-0.26	-0.20	13.53	0.35	10.26	67.16	-0.10	-0.01	-0.13	1.19	1.32	11.34	9.20	0.47	0.45	-4.10	0	0	0	0
2018	15.79	0.10	16.96	60.97	0.31	-1.19	-1.11	13.90	0.63	17.95	72.90	0.26	0.01	-0.14	1.54	1.69	46.54	73.73	0.37	0.25	-20.55	1	1	1	1
2019	15.30	-0.49	23.96	87.21	1.39	0.41	0.50	12.09	-1.28	21.78	85.24	0.88	-0.02	-0.20	2.06	2.03	5.34	7.24	0.62	0.60	5.56	0	0	0	0
2020	15.04	-0.85	22.36	78.11	0.79	0.26	0.37	12.28	-1.18	18.05	84.12	0.09	0.50	0.29	1.91	2.09	3.06	4.50	0.62	0.56	9.93	1	0	1	1
2021	16.58	0.59	14.41	56.32	-0.31	-0.40	-0.29	14.13	0.57	18.09	63.24	-0.05	0.26	0.02	1.30	1.18	38.49	58.28	0.41	0.33	-16.31	1	1	0	1
2022	16.44	0.35	9.72	51.02	-1.10	-0.10	0.04	15.23	1.58	8.98	51.37	-1.27	0.41	0.14	0.88	1.21	46.57	57.21	0.36	0.33	-22.15	0	0	0	0
2023	17.00	0.81	5.76	47.63	-1.29	0.10	0.24	13.60	-0.14	8.04	57.27	-1.32	0.47	0.17	1.26	1.00	42.77	53.50	0.39	0.33	-12.45	0	0	0	0
2024	14.08	-2.21	17.07	71.24	0.17	-0.71	-0.55	11.39	-2.45	21.94	79.97	0.71	-0.32	-0.65	2.32	2.01	14.30	28.89	0.55	0.46	2.89	0	0	0	0
2025	16.04	-0.34	4.69	54.42	-1.41	-0.11	0.06	14.09	0.15	4.39	53.55	-1.56	0.47	0.11	0.89	1.12	47.71	60.07	0.37	0.32	NaN	1	1	0	1