Section C - The Water Cycle and Water Insecurity Flashcards
What is the water cycle?
The cycle of processes by which water circulates between the earth’s oceans, atmosphere, and land
Stores in the water cycle - Hydrosphere, oceans - what percentage of the Earth’s water oceans contain?
The oceans contain 97% of Earth’s water
Processes of the water cycle - What is evaporation?
Heat from the sun causes water to evaporate
Processes of the water cycle - What is condensation?
Water vapour rises and condenses as clouds
Processes of the water cycle - What is advection?
Winds move clouds through the atmosphere
Processes of the water cycle - What is percipitation?
Water droplets fall from clouds as drizzle, rain, snow or ice
Processes of the water cycle - What is snowmelt?
Snow and ice accumulate, later melting back into liquid water or turning into vapour
Processes of the water cycle - What is surface runoff?
Water flows above ground as runoff, forming streams, rivers, swamps, ponds and lakes
Processes of the water cycle - What is interception?
Plants intercept percipitation falling from the sky
Processes of the water cycle - What is infiltration/percolation?
Water is soaked into the ground, flows below it, and seeps back out enriched in minerals
What is the % of total water, % of freshwater and residence time of oceans?
% of total water = 97%
% of fresh water = 0%
Residence time = 3600 years
What is the % of total water, % of freshwater and residence time of icecaps?
% of total water = 1.9%
% of fresh water = 68%
Residence time = 15,000 years depending on size
What is the % of total water, % of freshwater and residence time of groundwater?
% of total water = 1.1%
% of fresh water = 30%
Residence time = Up to 10,000 years for deep groundwater, 100-200 years for shallow ground water
What is the % of total water, % of freshwater and residence time of rivers and lakes?
% of total water = 0.01%
% of fresh water = 1.2%
Residence time = 2 weeks to 10 years
What is the % of total water, % of freshwater and residence time of soil moisture?
% of total water = 0.01%
% of fresh water = 0.05%
Residence time = 2-50 weeks
What is the % of total water, % of freshwater and residence time of atmospheric moisture?
% of total water = 0.001%
% of fresh water = 0.04%
Residence time = 10 days
Amazonia case study - average temp and climate
- 27 degrees C average temp in the amazon
- Warm and wet climate all year round
Amazonia case study - What % of global freshwater per day come from Amazon river discharge?
15%
Between 2000 and 2007 what was the Amazon’s rate of deforestation per year?
20,000 km2 per year
Brazil pollution stats (global polluter ranking and % of emissions used for land use change)
- Brazil is the 6th largest polluter in the world
- 75% of their emissions are from deforestation and land-use change
What are the impacts of human activity in the Amazon on the water cycle? (3)
- Extreme rainfall events could lead to more flash flooding events
- Overall reduction in river discharge
- 15% less water can be held in the soil - more easily eroded - faster rates of runoff
Have there been attempts to reduce deforestation in Brazil? (2)
- In 2008 the Zero Deforestation Campaign was proposed – this later became the Amazon Fund
- However, under Bolsonaro deforestation rates have risen significantly again, further threatening the Amazonia
Sahel case study - Type of hazard, when
- Drought
- Happening now
Sahel case study - Why is it happening and what are four human factors?
Changing rainfall patters caused droughts that have lasted for over a year - this has caused vegetation cover to wither and die, leaving soil exposed below – human factors are overgrazing, overpopulation, overcultivation, and human enhanced climate change
Sahel case study - Social impacts - What will happen to people’s land and what will this lead to?
If desertification continues to occur people will lose land that could be used for farming and livestock so they won’t be able to provide for their families leading to poverty and famine
Sahel case study - Economic impacts
The loss of arable land means less opportunities for people to sell and market food which would be the main source of income for people in these developing nations
Sahel case study - Environmental impacts
Loss of habitats due to desertification will mean a less diverse ecosystem and potentially endangering animals as humans will have to use other lands to make up for land lost to the drought – drought also dries up rivers
Sahel case study - Responses (changes in agriculture)
Encouraging farmers to grow drought resistant crops, using drip irrigation systems to reduced water usage