How has the percentage of water on Earth changed over geological time?

Over two billion people live in countries where water supply is inadequate. Half of the world's population could be living in areas facing water scarcity by as ... Feb 9, 2015 ... The Earth's surface is covered by 71% water and roughly 10% by ice. And I know the Earth is about 0.023% water by mass, but that's a comparison against the ... Although water covers 75 percent of the world's surface, 97.5 percent of the earth's water is salt water; of the remaining 2.5 percent, most is locked away as ... Basic drinking water services · World (2022) | 91.2% 78 ; Basic sanitation services · World (2022) | 80.6% 50 ; Basic handwashing facilities including soap and ... Aug 13, 2018 ... Canada has 7% of the world's renewable fresh water. ... For Canada's 30 million people -- about half a percent of the world's population -- this ... Nov 4, 2020 ... Water covers about 71% of the earth's surface. 326 million cubic miles of water on the planet; 97% of the earth's water is found in the oceans ( ... Freshwater makes up a very small fraction of all water on the planet. While nearly 70 percent of the world is covered by water, only 2.5 percent of it is fresh. Only 0.5 per cent of water on Earth is useable and available freshwater – and climate change is dangerously affecting that supply. Over the past twenty ... Oct 13, 2018 ... The country has an estimated 4.3 percent of the world's population yet contains more than 7 percent of global renewable freshwater resources. Lawrence River and their value to Canada and the United States are hard to imagine, even for residents of this region. The lakes hold 20 percent of the earth's ...