Human Factors Affecting the Water Cycle Flashcards
Human Activity Affecting Water Cycle Diagram
What is the average rate of deforestation in Amazonia from 1970 to 2013?
Deforestation in Amazonia averaged around 17,500 km²/year between 1970 and 2013.
What proportion of primary forest has been destroyed or degraded since 1970?
Since 1970, almost one-fifth of the primary forest in Amazonia has been destroyed or degraded (Figure 4.14).
Have rates of deforestation in Amazonia increased or decreased in recent years?
In recent years, rates of deforestation in Amazonia have slowed (Figure 4.15).
(This could be a good evaluation point)
What were the impacts of the devastating floods that occurred on the Madeira River in April 2014?
The devastating floods that occurred on the Madeira River in April 2014 resulted in vast expanses of floodplain being inundated, 60 people dying, 68,000 families being evacuated, and outbreaks of cholera and leptospirosis.
How has human activity modified stores and flows in the water cycle in the Upper Madeira drainage basin?
In the Upper Madeira drainage basin, human activity has modified stores and flows in the water cycle through deforestation, which has reduced water storage in forest trees, soils, permeable rocks, and the atmosphere. At the same time, fewer trees mean less evapotranspiration and therefore less precipitation. Meanwhile, total run-off and run-off speeds have increased, raising flood risks throughout the basin.
What was the main driver of the floods that occurred on the Madeira River in April 2014?
Despite torrential rains in the upper basin of the Madeira River, the main driver of the floods was deforestation in Bolivia and Peru. Between 2000 and 2012, 30,000 km² of Bolivian rainforest was cleared for subsistence farming and cattle ranching, resulting in a massive reduction in water storage and accelerated run-off.
What impact does converting rainforest to grassland have on run-off?
Converting rainforest to grassland increases run-off by a factor of 27, and half of all rain falling on grassland goes directly into rivers.
What role do rainforest trees play in the water cycle?
Rainforest trees are a crucial part of the water cycle, extracting moisture from the soil, intercepting rainfall, and releasing it to the atmosphere through transpiration, as well as stabilising forest albedo and ground temperatures. This cycle sustains high atmospheric humidity which is responsible for cloud formation and heavy conventional rainfall.
What impact can deforestation have on the water cycle?
Deforestation can break the water cycle, lead to reduced rainfall, and cause permanent climate change (Figure 4.17). Disruption of the regional water cycle means that forests hundreds of kilometres downwind of degraded sites are affected too.
What is the predicted impact of future deforestation in Amazonia?
Projections of future deforestation in Amazonia predict a 20% decline in regional rainfall as the rainforest dries out and forest trees are gradually replaced by grassland.
