Biological carbon and water cycle and how its threatened by humans Flashcards
What changes are there to land cover?
Farmland
Land drainage
Deforestation
Urbanisation
Industrialisation
Reservoir creation
What is driving the need for land use change?
growing demands for food, fuel and other resources
What are some examples of things that are meaning land conversion is needed?
Increased population growth
Increased economic growth in NICs
Improved living standards
What areas are undergoing land conversion?
Deforestation and conversion of grassland to farming mainly LICs and NICs
Afforestation mainly in HICs
How much of earths surface is forest?
30%
In how many years are rainforests expected to disappear?
Within 100 years
How many species from the rainforest go extinct each year?
4-6 thousand
How many people rely upon the rainforest?
2 billion
How do forests increase ground water stores?
roots increase space for water to infiltrate
DOM in soil acts like a sponge holding water
How do forests form a part of the hydrological cycle?
sends large amounts of water back into the atmosphere by evapotranspiration to fall as rain later or elsewhere
Where is deforestation mainly occurring? (general)
Poorer countries
What is the main driver of deforestation?
increasing demand for land for commodity production, half of all current deforestation is for soy, palm oil, beef and paper
What other causes for deforestation are there? (besides for commodities)
Dams and reservoirs
Infrastructure (roads, railway docks and airports)
Open cast mining
What is afforestation?
planting of trees on land that has never had trees or not for a long time
What is reforestation?
planting trees in places that was recently cleared of trees
What is the controversy with afforestation/ reforestation?
Impact on the landscape (e.g. UK upland)
Takes up land for food production
Ruins look of traditional landscape
What is ocean acidification?
the decrease in the pH of the worlds oceans caused by their uptake of carbon dioxide from the atmosphere
How much carbon did the IPCC say the oceans had absorbed in 2014?
30% of anthropogenic CO2 emissions
What is the scale for ocean acidity?
pH scale
Logarithmic ( each decimal point is a large % change)
What is neutral on the pH scale?
7 anything above is alkaline and anything below is acidic
What has the pH of the oceans been for the past 300 million years?
8.2
What happened to ocean acidity since the industrial revolution began?
fallen to 8.1 (30% drop)
What is the pH of the ocean thought to be at the end of the 21st century?
8.04-7.78
What is ecosystem resilience?
the level of disturbance that ecosystems can cope with while keeping their original state
What happens when a disturbance goes beyond a critical threshold?
an abrupt change may occur from the ecosystems original state to a new one
What is a positive feedback?
feedback mechanism increases original factor
What is a negative feedback loop?
feedback mechanism reducing original factor
When have the 3 main bleaching events occurred in the great barrier reef?
1998
2002
2016
How much has coral calcification fallen by in the great barrier reef?
44%
How does reducing albedo create a feedback loop?
warming climate cause ice and snow to melt, reducing amount of solar reflected into space, instead energy is absorbed by darker land and ocean causing more warming.
What is peat?
a type of carbon rich soil found in wet environments
How do increased forest and peat fires create a feedback loop?
Climate warms, peat dries, now able to catch fire, as carbon rich lots of CO2 released, adds to GHG effect, more warming and drying
Forests are the same (but changing rain patterns cause drought and drying)
When have the main amazon rainforest droughts been?
2005
2018 (15yr of carbon emissions released)
