Answer: The correct answer is salinity.
Step-by-step explanation:
Salinity is define as sum of all the salts which are dissolved in water.
It is caused by the evaporation of the water from the surface of the water bodies due to which amount of water present in the water bodies decreases and amount of salt dissolved increases. By increase in the salt amount in water bodies salinity increases.
Where as other options are consequences of the of rising average air temperatures on Earth.
Hence, the correct answer is salinity.