There are three drivers here:
1. Food creation: this is the supply side. All things being the same, the supply is falling short.
2. Food consumption: All things being the same, somehow we are consuming more so there is a shortfall.
3. Food migration: If no change in supply or demand, then there is an export/import imbalance somewhere.
For #1: reasons are (a) change in weather or seasonality (2) crop quality / diseases (3) transportation issues - delays or waste etc (4) less farmers in general
To fix is a combo of (a) cold storage tech (2) better distribution of pesticides, other quality assurance tech, better seeds, etc (3) better supply chain (4) subsidies / tax benefits for farming, better loans etc.
For #2: reasons are (a) population growth (b) per capita growth in eating vol? / obesity? (c) food wastage
To fix, some solns are (a) policies around pop control / education (b) healthy diet recos / education (c) better policies on recycling as well as penalties for wastage, reduce service sizes, bla bla
For #3: reasons are (a) increased demand for certain crops abroad (b) price arbitrage - more profitable to export than keep domestic, etc..
To fix, you could (a) incent farmers to produce more of the high-demand crops (b) import/export tax incentives, etc.
Hope this helps.