Fig 1.
Coffee regions and production cycles.
(a) Percentage of 2019 coffee yield by primary coffee species per region. Robusta regions are to the right of the red line, plus northern Brazil. Dashed lines indicate regions used to calculate ocean modes indices. (b) Flowering and growing seasons, with percentage of 2019 coffee yield by species shown on the right-hand axis. The map base layer is available from Natural Earth at https://www.naturalearthdata.com/downloads/110m-physical-vectors/110m-coastline/.
Table 1.
Details of the climate hazards used in this study.
Fig 2.
Susceptibility to climate hazards.
Number of years between 1980 and 2020 during which climate variables surpass biophysical coffee thresholds for (a) high growing-season VPD (VPDgr) or low flowering-season minimum temperature (Tmin,fl), (b) high growing-season maximum temperature (Tmax,gr) or minimum temperature (Tmin,gr), (c) and (d) low and high growing-season mean temperature (Tgr), (e) and (f) low and high annual precipitation (Pan). Robusta regions and corresponding hazard definitions are to the right of the red line, plus northern Brazil. The map base layer is available from Natural Earth at https://www.naturalearthdata.com/downloads/110m-physical-vectors/110m-coastline/.
Fig 3.
Average number of climate hazards per year 1980–2020.
Robusta regions and corresponding hazard definitions are to the right of the red line, plus northern Brazil. The map base layer is available from Natural Earth at https://www.naturalearthdata.com/downloads/110m-physical-vectors/110m-coastline/.
Fig 4.
Regional events by climate hazard 1980–2020.
Time series show the occurrence of climate hazards for each region, for (a) growing season VPD (VPDgr) and maximum temperature (Tmax,gr; Arabica), and minimum temperature in the flowering (Tmin,fl) and growing (Tmin,gr) seasons (robusta), (b) growing season mean temperature (Tgr) and (c) annual precipitation (Pan).
Fig 5.
Regional events for all climate hazards 1980–2020.
The main panel shows the number of hazard events per region and year. Shading indicates whether the majority of hazards are ‘warm or dry’ (brown) or ‘cold or wet’ (green) according to Table 1. On four occasions, one hazard from each of these classifications occurred (pink). The right-hand bar plot shows the number of hazards per region over the whole period. The top bar plot shows the number of hazards per year across all regions. These bar plots are shaded according to whether they are ‘warm or dry’ or ‘cold or wet’.
Fig 6.
Relationship between climate modes and surface variables.
Spearman correlation between detrended growing season ENSO (measured by Niño3.4), Indian Ocean Dipole (DMI), Tropical North Atlantic index (TNA), Madden-Julian Oscillation indices for phases 1 and 4 (MJO1 or MJO4), and detrended growing season mean temperature (left column) or annual precipitation (right column). Robusta regions are to the right of the red line, plus northern Brazil. The map base layer is available from Natural Earth at https://www.naturalearthdata.com/downloads/110m-physical-vectors/110m-coastline/.
Fig 7.
Detrended climate hazards and mode indices time series.
(a) Number of hazards per year across all regions. Circles and triangles denote years that featured above average numbers of ‘cold or wet’ and ‘warm or dry’ hazards, respectively. (b) Mode indices averaged across all regions’ growing seasons. The indices are standardised by dividing by their standard deviation in time. The mode indices are for Niño3.4 (ENSO), the Indian Ocean Dipole Mode index (IOD), the Atlantic Niño index (Atl. Niño), the Tropical North and South Atlantic indices (TNA and TSA) and the Madden-Julian Oscillation indices for each of the eight phases (MJO1 through MJO8).
Fig 8.
Climate modes during detrended spatially compounding warm/dry and cold/wet years.
(a) Mean of standardised climate mode indices over years that featured above-average numbers of ‘warm or dry’ or ‘cold or wet’ hazards. Black circles indicate statistical significance. (b)-(e) Hazards per year plotted against ENSO (Niño3.4), Madden-Julian Oscillation phase 1 (MJO1), TNA and Madden-Julian Oscillation phase 4 (MJO4) indices, shaded according to ‘warm or dry’ (brown) and ‘cold or wet’ (green) hazards.
Fig 9.
Important climate modes for regional climate hazards.
Standardised regression coefficients of explanatory variables for the best-performing Gaussian GLM models. Positive coefficient values indicate a positive relationship between the explanatory variable and the number of warm or dry hazards. Negative coefficient values indicate a positive relationship between the explanatory variable and the number of cold or wet hazards. The explanatory variables are Niño3.4 (ENSO), the Indian Ocean Dipole Mode index (IOD), the Atlantic Niño index (Atl. Niño), the Tropical North and South Atlantic indices (TNA and TSA) and the Madden-Julian Oscillation indices for each of the eight phases (MJO1 through MJO8).