Impacts of Climate Change (Edexcel A Level Geography)
Revision Note
Written by: Bridgette Barrett
Reviewed by: Jenna Quinn
Impact of Climate Change on Inputs & Outputs
The impact of climate change on the hydrological system could lead to several different impacts
Summary of Climate Change Impacts on Inputs and Outputs
Impact on | Result |
|---|---|
Precipitation | Warmer air holds more water, therefore, there would be an increase in rainfall frequency and intensity; areas most affected would be the tropics and high latitudes Decreases in precipitation would most likely lie between 10° and 30° north and south of the Equator Increased frequency and length of heatwaves, increasing occurrences of drought and water scarcity Snowfall is replaced with rain in northern regions, reducing glacier mass |
Soil Moisture | Where areas see an increase in precipitation then it would follow that soil moisture will increase also and vice versa Overall impact of climate change is uncertain as many factors contribute soil moisture levels and climate is just one factor |
Evapo-transpiration | Increased evaporation over large land masses such as North America and Asia Transpiration levels would alter inline with vegetation changes (increase or decrease), this would further link to changes in soil moisture and precipitation |
Impact of Climate Change on Stores & Flows
It is expected that climate change will reduce stores, and increase flows
However, there is uncertainty surrounding this as more research is needed to establish a definite link between climate change and the hydrological cycle
Store | Impact |
|---|---|
Ice | Higher temperatures lead to negative mass balance Shrinking of glaciers, ice caps and ice sheets Reduction of glacial water for human use |
Oceans | Possible increase in evaporation Rise in sea levels as warmer waters expand Rise in frequency and intensity of tropical cyclones Storage capacity increased by meltwater |
Snow | Decreased length of snow cover seasons - economic impact on tourism revenue Spring melt starts earlier |
Permafrost | Melting of permafrost and release of methane to the atmosphere, increase of greenhouse effect (positive feedback) Changes to the ecosystems and tundra reducing stores of water |
Surface Runoff and Stream Flow | Increased low and high flow events (drought and floods) Reduced infiltration with increased surface runoff |
Groundwater Flow and Aquifers | Abstraction of water makes impact uncertain Aquifers depleted through over abstraction but also low flow events not recharging store |
Soil Moisture | Little change |
Reservoir, Lake and Wetland Storage | Human activity changing wetlands cannot be linked to climate change, however, there does appear to be a link with decreasing stores and temperature rises |
Climate Change & Water Security
It is necessary to distinguish between long term climate change impacts and the short term oscillations of ENSO cycles
ENSO cycles result in both extreme flooding and drought in different parts of world at the same time
However, if land and sea surface temperatures continue to rise, then it is possible ENSO cycles could become more frequent rather than every 2-3 years
This would lead to more periodic unusual climates for both South America and Australia
It would also lead to unreliable patterns of rainfall and failure of monsoons impacting many tropical monsoon climates (India etc.)
Increased intensity and frequency of drought impacts agriculture raising water insecurity
Loss of snow and glacier melt threatens many communities particularly in mountainous areas
Greater rates of evapotranspiration and desiccation of forest stores
Increased temperatures lead to greater evaporation from surface water and reservoirs, reducing levels of water and increasing risk of water borne disease and mosquitos
Depleted aquifers leads to water insecurities and lowering of water table
Examiner Tips and Tricks
It is important to note that drainage basins and the water cycle depend on ENSO cycles and climate, both are unpredictable and not that well understood. That makes managing the future of our water challenging.
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