They both mean "lack" in English. However,is there any difference in the usage? Thanks a lot!
'Escasear' is when there is insufficient amount of something and it's used only with uncountable things. 'Faltar' is closer to 'miss', and it's the only one you can use when there is nothing at all of something.
- Escasea la comida = There isn't enough food
You could also say:
- Falta comida (uncountable) - There isn't enough food
but if you say
- Falta la comida (countable), the meaning is The food is missing
You can say:
- Falta un zapato = A shoe is missing
but you can't say
- Escasea un zapato