Data Methodology
Version 1.0 · June 2026 · Open methodology — free to cite with attribution
1. Data Sources
2. Calculations
ENSO Phase Classification
El Niño: ONI ≥ +0.5°C for ≥5 consecutive overlapping 3-month periods
La Niña: ONI ≤ −0.5°C for ≥5 consecutive overlapping 3-month periods
Neutral: −0.5°C < ONI < +0.5°C
Strength:
Moderate: ±0.5°C to ±0.9°C
Strong: ±1.0°C to ±1.4°C
Very Strong: ≥ ±1.5°C
Follows NOAA CPC standard definitions.
Agricultural Temperature Anomaly
Anomaly (°C) = T_current − T_climatological_mean
T_climatological_mean = 1991–2020 monthly mean at monitoring coordinate
Significance threshold: |anomaly| ≥ 1.5°C flagged as potential crop stress
Commodity Price Change
MoM Change (%) = ((P_latest − P_previous) / P_previous) × 100
P_latest = most recent World Bank monthly value
P_previous = immediately preceding monthly value
Crisis-to-Commodity Impact Estimates
Directional impact estimates in the Impact Chain are derived from: (1) historical ENSO-commodity price correlation analysis 1985–2024; (2) published research cited in the Science Hub; (3) current event severity and affected region agricultural exposure; (4) expert assessment of supply disruption magnitude. These are directional assessments — not precise price forecasts.
3. Agricultural Monitoring Locations
- Argentine Pampas — 34°S 64°W — Soybeans · Climatological mean: 14.2°C
- Brazilian Cerrado — 15°S 47°W — Coffee, Sugar · Climatological mean: 24.1°C
- SE Asia Delta — 13°N 101°E — Rice · Climatological mean: 29.3°C
- US Corn Belt — 41°N 93°W — Corn, Wheat · Climatological mean: 16.8°C
- East Africa — 0° 37°E — Coffee, Grains · Climatological mean: 21.4°C
- SE Australia — 33°S 149°E — Wheat · Climatological mean: 13.9°C
4. Limitations
World Bank Pink Sheet data published with 2–4 week lag. Not real-time market prices. For futures data: configure Alpha Vantage API key in platform settings (My Wave).
Temperature anomalies measured at single-point coordinates. Not gridded spatial averages. May not reflect conditions across an entire agricultural region.
Crisis-to-commodity impact estimates indicate likely direction of price movement based on historical patterns. Not precise forecasts. Many factors influence commodity markets beyond the events tracked here.
GDACS covers internationally-reported events. Slow-onset events (progressive drought) and events in regions with limited reporting infrastructure may not appear.
5. Citation Guidelines
All El Niño One Wave data is free to use, reproduce, and cite. No permission required.
Data enquiries: data@elnino-onewave.pages.dev