Changes over Time to the Water Cycle Flashcards
What are the 5 natural processes that cause a change to the water cycle?
Seasonal Changes, Storm events, Droughts, El Nino and La Nina and Cryospheric Processes
How do storm events cause a change over time
Cause sudden increases in rainfall, leading to flooding and replenishment of some water stores. It is unlikely to cause a long term change
How do droughts cause a change over time?
They cause major stores to be depleted and the activity of flows acting within the water cycle to decrease. It may cause long-term change as they become more common as a result of climate change.
What is the El Nino effect?
It occurs every 2-7 years and causes warm temperatures in a predictable way
What is the La Nina effect
It occurs every 2-7 years and causes cooler temperatures in a predictable way
How have cryospheric processes changed the water cycle over time?
In the past glaciers and ice caps have stored significant proportions of freshwater through the processes of accumulation. Currently almost all of the worlds glaciers are shrinking causing sea levels to rise.
How many metres would sea levels rise if all glaciers and ice caps were to melt?
60 metres
What are the three human impacts?
Farming Practices, Land Use Change and Water Abstraction
How does Farming Practices change the water cycle over time?
- Ploughing breaks up the surface increasing infiltration
- Crops can increase interception and evapotranspiration
- Animal farming compacts soil, reducing infiltration and increasing runoff
- Irrigation removes water from local rivers, decreasing their flow.
How does Land Use Changes change the water cycle over time?
- Deforestation reduces interception and evapotranspiration but infiltration increases.
- Construction reduces infiltration and evapotranspiration, but increases runoff.
How does Water Abstraction change the water cycle over time?
It reduces the volume of water in surface stores and also leads to an increase in dry seasons. Abstraction from aquifers can also lead to a decline in global long-term water stores.
