Hydrosphere

The hydrosphere (from Greek hydor for water) comprises all water on Earth. Water exists on Earth as surface water (e.g. oceans, lakes, rivers), in the form of groundwater under the surface of the Earth, and in the atmosphere. Moreover, the frozen water bodies of the mountain glaciers, polar ice caps and sea ice are part of the hydrosphere.

In total Earth’s hydrosphere contains more than 1450 million cubic kilometers of water. The majority of this water, about 94%, forms the oceans.

Water in many respects is one of the key components of the Earth system. Due to the current temperatures on Earth water exists as gas, as a liquid and in solid form. This is the reason why it can participate in numerous processes on Earth. Many of these processes are vital for the existence of life.

Select your Case Study:

Coasts as dynamic boundaries
	Alexandria, Egypt Sea level rise and reduced sediments from the Nile river modify the coastline.
	Thames Estuary, UK Offshore windfarms are an important component producing renewable energy and shape coastal regions.
	Mississippi Delta, U.S.A. The delta of the Mississippi is a highly dynamic and extensively used coastal region.
	Gibraltar, UK The Strait of Gibraltar is an important gate for ship traffic between the Atlantic Ocean and the Mediterranean Sea.
Water surface temperaturess
	Gulfstream and North Atlantic Current Important components of the global system of ocean currents, transporting warm water towards the coasts of northwestern Europe.
	El Niño and La Niña An important (quasi)periodical phenomenon in the equatorial Pacific Ocean with strong influence on the weather conditions in remote areas.
Glaciers as water bodies
	Columbia Glacier, U.S.A. Higher temperatures and the rising sea level lead to a rapid decay of the Columbia Glacier.
	Aletsch Glacier, Switzerland The largest glacier of the Alps is an example of the retreat of alpine glaciers.
	Kilimanjaro Glacier, Tanzania There are not many glaciers in the tropical climate zone, and they are shrinking.
Floods and flood protection
	Plattsmouth, U.S.A. Heavy rainfall in the Missouri Basin has caused severe floodings in 2019.
	Derna, Libya Unusually heavy rainfall caused a dam failure and a disastrous flooding in 2023.
	Venice, Italy To cope with the threat of the rising sea level, the flood protection system MOSE has been installed.