Collapse

tl;dr: By 2050 global production of staple crops could fail every other year.

Changes in the probability of a crop yield failure across the global breadbaskets of maize, wheat, rice, and soybean are projected throughout mid-century. Yield failure probability varies by global crop breadbasket with large differences in runs without and with CO2 fertilization (table 1). Without CO2 fertilization, the probability of a crop yield failure increases to at least 50% with the exception of wheat (42%) in any given year in 2041–2060. Presently, rice and maize failures are extremely unlikely. By mid-century, a rice or maize failure within global breadbaskets will occur at least every other year.

The "CO2 fertilization" mentioned here is increased plant growth due to higher CO2 levels and is theorized to potentially offset losses in wheat and rice.

But ...

Global greening from CO2 fertilization appears to have reversed around 20 years ago.

Here we use multiple long-term satellite leaf area index (LAI) records to investigate vegetation growth trends from 1982 to 2018. We find that the widespread increase of growing-season integrated LAI (greening) since 1980s was reversed (p-value < 0.05) around the year 2000 over 90% of the global vegetated area, and continued in only 10% of the global vegetated area. The reversal of greening trend was largely explained by the inhibitive effects of excessive optimal temperature on photosynthesis in most of the tropics and low latitudes, and by increasing water limitation (increasing in atmospheric vapor pressure deficit and decreasing in soil water availability) in the northern high latitudes (>45°N).