Complex sentence: The melt also increases ocean levels and decreases the availability of water for human consumption, agricultural, hydroelectricity, adding to issues from sanitation to hunger to population shifts, and catastrophic weather such as flooding, drought, and temperature fluctuations.
Split into simpler sentences: The melt also increases ocean levels and decreases the availability of water for human consumption, agriculture, and hydroelectricity. This aggravates and increases the likelihood of issues such as sanitation, world hunger, population shifts, and catastrophic weather such as flooding, drought, and world-wide temperature fluctuations.