Earth is a blue watery planet.
70% of its surface is covered by oceans of salt water, some of which are extremely deep. These oceans contain about 97% of Earth’s water. Another 2% is locked up in snow, ice caps and glaciers. That leaves just 1% of Earth’s surface water in inland seas, lakes, rivers and dams. We have plenty of water, but not much to drink.
In addition to these vast surface water supplies, water vapour is the fourth most abundant gas in the atmosphere, after nitrogen (76%), oxygen (21%) and Argon (1%). Moisture in the atmosphere varies from almost zero over deserts and ice caps up to 4% over the wet tropics. (Carbon dioxide is a miniscule 0.04%).
