In 50 years, the human population will reach 8.6 billion, which means we'd need land “roughly the size of Brazil” just for growing crops to sustain the human population. Rather than expanding out, some are suggesting we grow upwards, via vertical farming. Out in the oceans, fish farms sometimes have fishbreaks, when farmed salmon, cod, and trout break free from defective cages and escape into the open ocean. Not only is this millions of dollars of lost revenue for fish farmers, the freed fish could also wreck the surrounding ecosystem.
– The Atlantic