How Feedbacks within and Between the Water & Carbon Cycles Links to Climate Change

Where the fluxes (transfers) within the stores and processes of both cycles change this can increase the likelihood of global climate change.

Distinct changes occur mainly as a result of human processes.  Anthropogenic release of carbon dioxide and methane can result in a rapid warming effect on the earth as solar radiation is trapped in the lower atmosphere and can’t escape to space so easily.  This increase of atmospheric carbon gas occurs due to the activities of an ever increasing human population.  

Rising demand for food has led to a greater methane output as a result of cattle (digestion) and rice farming (marsh gas).  The burning of hydrocarbons for heating, electricity generation and transport has been a major factor releasing carbon from long-term fossil-fuel stores.  Human destruction of natural vegetation has reduced a natural climate sink that would otherwise absorb atmospheric carbon. 

Changes to climate can then affect the processes and stores of both the carbon and water cycles. 

Water cycle: 

• A warming world is leading to a change in water cycle processes.  Cryosphere stores are shrinking leading to an increase in hydrosphere stores.
• Regionally, rainfall patterns will alter, with some regions receiving more rain and others receiving much less than has been normal.
• A colder world increases cryosphere and reduces hydrosphere stores.  Lithosphere and atmosphere storage decline but to a much lesser degree.

Carbon cycle:

• Climate change also impacts upon carbon cycle processes.  The natural storage of carbon, in particular in the oceans, the soil and vegetation can be affected by climate change. Warmer oceans are less able to absorb atmospheric carbon dioxide and melting cryosphere soils are beginning to release significant quantities of stored methane from accumulated tundra peats. Both can amplify global warming through a positive feedback cycle.  Equally, changes in global temperature will result in widespread extinction of many vegetation species through the inability to survive in a warmer or drier world.  Also, in a warmer climate where rainfall is less, many species can’t adapt - so ultimately die or will be affected by large scale forest fires, which are becoming more frequent in certain areas of the world.  The release of extra CO2 from forest fires will only exacerbate the climatic change occurring.