Fig 1.
(Top panel). The climate impact on national food supply based on consumption and domestic perspective under additional 2°C global warming. We compare the crop-aggregated domestic climate impact (sensitivity of crop yields of wheat, maize, and rice to future warming) (x-axis, S4 Fig) to the consumption impact on calorie supply i.e., climate impacts on both domestic and overseas supplying regions (y-axis, S4 Fig). Positive impact values suggest more calories are projected to be available because of warming and negative impact values suggest fewer calories are projected to be available. Climate impact is aggravated when consumption impact increases the detrimental effect (lower loss to higher loss or gain to loss) or decrease the beneficial effect of climate change (from higher gain to lower gain) on the total calorie supply i.e., consumption impact is worse than domestic impact. Climate impact is mitigated if the opposite is the case, i.e., consumption impact decreases the detrimental impact (higher loss to lower loss) or increase the beneficial impact (lower gain to higher gain or loss to gain) on the total calorie supply. No effect on climate impact is considered when domestic impact and consumption impact are close to each other, where close is defined based on the lowest 5th percentile of the shortest distance between each point on the plot and the 1:1 line. The color of the data points corresponds to the World Bank income classification for the corresponding year and the size of the data points are scaled to 2010 national populations. Top panel (inset): We show the percentage of countries under each income class for which climate impacts are aggravated, mitigated, and shows no change under consumption impact. Bottom panel: The map shows the countries for which climate impact is mitigated (blue), aggravated (orange), and has no effect (white) on food supply for the three crops aggregated. For countries in gray, the impact estimates are not included. The map is generated using R version 4.2.1 and shapefiles sourced from the NaturalEarth project (naturalearthdata.com).
Fig 2.
In this figure, we show the different factors influencing the consumption impact.
For all the maps we consider 2°C mean global warming relative to the level of recent warming and fixed 2010 trade-portfolios. We divide this figure into three panels (a-c) horizontally, each panel containing three columns corresponding to the three crops- wheat, maize, and rice (from left to right). The panel a) shows the cross-border effect (as percentage impact per unit calorie) on total food supply of a particular country. The positive values mean that more calories will be available due to 2°C future mean global warming and negative values mean fewer calories (in percentage) will be available. The panel b) shows the import dependence (in percentage) of each country defined as the proportion of their crop-specific supply being sourced from other countries. In the panel c), we show the difference in import and domestic production impacts. For countries in gray, the estimates are not included. The inset table shows the global average (range) values for the variable shown in the three panels by crop. The maps are generated using R version 4.2.1 and shapefiles sourced from the NaturalEarth project (naturalearthdata.com).
Fig 3.
Visualizing how climate impacts are manifested for major import-dependent countries.
The two panels correspond to 1°C and 2°C future mean global warming conditions relative to the level of recent warming (top & bottom). Each bar corresponds to a particular import-dependent country as labelled on the y-axis (see S1 Table for country codes). Each bar is made up of multiple stacks of different lengths and colors. Each stack corresponds to a particular country supplying calories to the importing country (labelled on the y-axis). The length of each stack (measured on the x-axis) within each bar corresponds to the proportion of total calories supplied by that supplying country to the importing country. The color of each stack represents the crop-aggregated (wheat, maize, and rice) climate change impact on domestic production of the supplying country under different warming scenarios.
Fig 4.
This figure shows for which countries mega-exporters aggravate (orange) or mitigate (blue) the climate impacts.
The central map shows the various mega-exporters identified through our analysis. Each panel on the four corners shows a particular mega-exporter (panel label) and the role it plays in mediating the climate impacts for countries that source calories from it. For readability, we only show four of the nine mega-exporters and the importing partners that rely on a particular mega-exporter for at least 10% of their calorie supply from wheat, maize, and rice aggregated. The figure shows that 37 countries rely on the USA, 22 on France, 11 on Germany, and 11 on Russia for at least 10% of their total calorie supply. The maps are generated using R version 4.2.1 and shapefiles sourced from the NaturalEarth project (naturalearthdata.com).