About what percentage of the Earth's total water is found in the oceans?

The oceans hold about 97 percent (often given as 97.2 percent) of all the water on the Earth. This water is salty and cannot be used directly for drinking, farming or most industries.

Distribution of the Earth's water:

• Oceans and seas: about 97 percent (salt water).
• Fresh water: only about 2.5 to 3 percent.

Of the fresh water:

• About 68 to 70 percent is locked in ice caps and glaciers, mainly in Antarctica and Greenland.
• About 30 percent is groundwater, stored underground in soil and rock layers called aquifers.
• Less than 1 percent is surface water in lakes, rivers, swamps, soil moisture and the atmosphere.
• So, the fresh water easily available to humans in lakes and rivers is a tiny fraction, less than 0.01 percent of all water on Earth.

The water (hydrological) cycle:

• Water evaporates from oceans, lakes and land, and plants release water vapour through transpiration.
• The vapour condenses to form clouds and falls back as precipitation (rain, snow and hail).
• Water returns to the oceans through rivers and groundwater flow.
• The oceans are the main source of evaporation and the main store of the cycle.

Why the oceans are important:

• They regulate the Earth's climate by storing and transporting heat.
• They absorb a large part of the carbon dioxide released by human activities.
• Tiny marine plants (phytoplankton) produce a large share of the Earth's oxygen.
• They provide food, minerals, energy and transport routes.

India and water:

India has about 18 percent of the world's population but only about 4 percent of its fresh water resources, so water conservation is very important.

Why not the other options?

• ✗About 85 percent and about 50 percent are incorrect.
• ✗About 2.5 percent is roughly the share of fresh water.