For a surface low to develop into a major storm system, the upper-level divergence of air must be surface convergence of air.

Storms can harm lives as well as properties via heavy rain, storm surge that would cause flooding yet there are systems having significant rainfall helping alleviate drought in some places. For a surface low to develop into a major storm system, upper level divergence of air should be greater than the surface convergence of air.

Humans increased food production by farming.

Answer decreased soil salinity;