water and carbon -amazon rainforest case study (water cycle in the amazon)

Question 1

how has human activity impacted the water cycle in the amazon?

Answer 1

.clearance for cattle ranching is responsible for 80% of deforestation
.deforestation has a massive impact on the rainforest water cycle

Question 2

what average rate has the size of the rainforest been declining by?

Answer 2

0.3% per year since 2000

Question 3

what are some examples of the impacts on the water cycle from human activity?

Answer 3

.atmosphere becomes less humid as evapotranspiration is reduced.
.with less trees, most rainfall reaches the ground immediately, compacting it and leading to increase rates of overland flow leading to increased risk of flooding.
.ground becomes exposed to the sun so the soil will become very dry and vulnerable to erosion which limits the chance of regrowth.

Question 4

what are the local impacts of deforestation -supressing precipitation?

Answer 4

.supressing precipitation -replacement of forests by pasture or crops = reduced atmospheric humidity = supressed precipitation

Question 5

what are the local impacts of deforestation -altering precipitation?

Answer 5

.increase in rainfall due to vegetation breezes
.air over cleared land warms faster, rises quicker and creates localised low pressure resulting in thunderstorms and heavy rainfall
.heavy rainfall increases surface flow meaning the soil is more prone to erosion

Question 6

what are the local impacts of deforestation -burning and cloud formation?

Answer 6

.burning forest areas as a way of removing trees produces ultrafine airborne aerosols around which vapour condenses
.scientific studies suggest that water droplets forming around the ultrafine aerosols result in droplets too small to form rain clouds

Question 7

what are the regional impacts of human activity in the amazon rainforest?

Answer 7

.rainfall levels in wider regions are most likely to reduce
.future deforestation of the amazon could lead to 20% declines in regional rainfall