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THREATS TO THE WATER AND CARBON CYCLE - Coggle Diagram
THREATS TO THE WATER AND CARBON CYCLE
DEFORESTATION
FOREST COVER around 30% of the Earth’s land area.More than half of forested land is cleared due to increased demand for commodity production: soy, palm oil, beef and paper production. Land is also being converted to build dams and reservoirs, therefore land clearing may increase as energy demands increase or water supplies decrease. By 2015, 30% of all global forests had been cleared. Annually, around 13 million hectares are lost every minute
TREE LOSS
A loss of even a small number of trees can disrupt weather patterns which could lead to more intense flooding and droughts.
CARBON CYCLE
▪ Reduction in carbon stored in biosphere.
▪ Reduction in carbon absorbed for photosynthesis.
▪ More carbon released from combustion.
WATER CYCLE
▪ Less interception so more surface runoff and shorter lag time.
▪ Shorter lag time will increase flooding risk.
▪ More soil erosion as there are no tree roots to bind soil together.
▪ Eroded material in rivers.
▪ Less evaporation from vegetation
REGIONAL TRENDS
▪ 90% of forests in the UK and USA were lost through deforestation by the 19th century.
▪ Boreal forests have been threatened in Russia and Canada for oil and tar sands production.
▪ In Africa and South America, most forests have halved in area since the 1960s
▪ In Indonesia, large areas of forest land have been cut down or burnt to make way for palm oil plantations for which demand is increasing significantly.
HUMAN WELLBEING
Over 1.6 billion people depend on forests and more than 90% of these people are amongst the poorest in society. Between 2000 and 2010, deforestation affected 13 million hectares of forest every year. Many people join pressure groups like Greenpeace and the WWF to oppose forest loss. Greenpeace found that TNCs don't do enough to prevent deforestation, forest fires and human rights abuses.
GRASSLAND CONVERSION
TYPES OF GRASSLAND
Temperate grasslands which have no trees
Tropical grasslands or Savannahs which have trees but infertile soil
ROLE OF GRASSLAND
● Traps moisture and floodwater
● Absorb toxins from soil
● Provide cover for dry soils
● Provides habitats for wildlife
● Act as a carbon sink
CARBON CYCLE
Release CO2 into atmosphere initially.
There is a net increase in CO2 emissions as biofuel crops need fertilisers.
Cultivated soil is more susceptible to erosion
OCEAN HEALTH
Oceans absorb around 30% of the atmosphere’s CO2 . Since 1800, around 50% of all carbon emissions came from the combustion of fossil fuels. As CO2 in the ocean increases, the pH of the ocean decreases (increasing acidity)
OVER FISHING creats imbalance in ocean health
▪ Fishing supports 500 million people of which 90% live in LDCs.
▪ Fish is a cultural choice for wealthy MEDCs where as it is a necessity for people in LEDCs.
▪ Millions of small-scale fishing families depend on seafood for their income as well as for food.
TOURISM
many countries rely on their marine life to attract tourism. Therefore overfishing and acidification (affecting coral reefs) can have direct consequences for a country’s economy and employment.
WILDLIFE IMPACT
As oceans become more acidic, corals cannot absorb alkaline CaCO3 in order to maintain their skeletons, in turn reefs begin to dissolve. Algae provide food to corals through photosynthesis. If the water becomes warm enough, the algae leave the coral, leaving the coral to turn white (Coral bleaching).
CORAL
Shelter 25% of marine species
Protect shorelines
Support fishing industries
Provide income through tourism
CLIMATE CHANGE
CLIMATE CHANGE
Increased carbon emissions are enhancing the greenhouse effect significantly and this is affecting the world’s climate.
WATER CYCLE AND CLIMATE
More frequent and more intense storms and hurricanes.
Rising sea levels, therefore more coastal erosion and some land lost (isostatic sea level rise).
More frequent floods, droughts and heatwaves.
CHANGES Changes in ocean currents and atmospheric circulation could have an impact on patterns of
precipitation, evapotranspiration and temperature.
unsualy weather patterns seen in 2015 too eg walm in russia, flooding in europe, droughts in pakista
FUTURE Scientists have use climate model simulations to investigate shifts in climate zones. They believe that for and increase of 2 degrees, 5% of the Earth’s land area shifts to a different climate zone.
CARBON CYCLE
more CO2 being released from boreal forests as they become drier and forest fires start.
CH4 from thawing permafrost.
CH4 from the destabilization of wetlands
Loss of Arctic Albedo (white snow reflects solar radiation, earth and dark surfaces will absorb solar radiation) may lead to increased permafrost thawing. If some arctic bogs thaw, huge quantities of methane and CO2 gas will be released into the atmosphere, leading to irreversible changes to climate.
Greenhouse gases are likely to increase in the future as more countries industrialise and develop. Greenhouse gases remain in the atmosphere for a long time and so even if global emissions were reduced, surface air temperatures would still continue to increase.
It is very difficult to predict future emission levels and so scientists use various scenarios to show projected greenhouse gas concentrations. There are several uncertainties in estimating future Climate Change, but they have identified several tipping points and feedback mechanisms that scientists believe would accelerate change.
UNCERTAINTIES
● Oceans and forests are carbon stores.
● Oceans take a very long time to respond to changes in greenhouse gas concentrations.
● Weather will have a direct influence over vegetation productivity and the rate of chemical reactions. As how climates will change is unknown, future vegetation changes is also unknown.
HUMAN FACTORS
▪ Population change – Increasing affluence in emerging economies means that that by 2050 there could an additional 1 billion consumers which could lead to more emissions due to more energy consumption.
▪ Technology & Globalisation - Increased globalisation leads to more traveling and transportation of goods which could mean more emissions. However, technological advancements may compensate and decrease emissions created by the inteconnected world.
▪ Economic growth – There is a correlation between economic growth and energy consumption. After the financial crisis in 2007, there was concern that CO2 emissions would begin to rise as GDP growth picked up.
FEEDBACK MECHANISMS
NEGATIVE = dampens origanal process
POSITIVE = applifies original process
PEATLAND - POSITIVE FEEDBACK OF CLIMATE CHANGE
Peat is the accumulation of partly decayed vegetation, which stores a large amount of carbon. Warming causes peat to dry out and the rate of decomposition increases. An increase of 4 degrees causes a 40% loss of soil organic carbon from shallow peat and 86% from deep peat. Peatlands emit carbon in the form of methane which increases greenhouse gases and accelerates enhanced Greenhouse Effects.
PERMAFROST POSTIVE FEEDBACK OF CLIMATE CHANGE
When permafrost melts, trapped carbon is released into the atmosphere as CO2 and methane which increases greenhouse gas concentrations in the atmosphere. This leads to higher temperatures and further melting of ice.
TIPPING POINTS
TIPPING POINT critical threshold, when reached small changes in global climate system can transform a stable system irreversibly
FOREST DIE BACK
Forest Die-back Rainfall in the Amazon is largely recycled. If there is a drought in the rainforest, trees may die. A tipping point could be reached when moisture can no longer be recycled (due to too few trees to intake moisture) which leads to more trees dying. In the boreal forest ecosystem, hot and dry summers lead to water stress which can result in a loss of trees. A tipping point could be reached when trees no longer absorb much CO2 which in turn increases the concentration of greenhouse gases in the atmosphere, leading to further dry summers.
THERMOHALINE CIRCULATION
Circulation Cold water in the North Atlantic forms part of the thermohaline circulation. To keep warm water heading from the tropics towards Britain, heavy water must sink in the North. The melting of Northern ice sheets releases large amounts of fresh water into the ocean which is less dense and has low salinity. This will disrupt the circulation of water, affecting the temperature of the ocean reaching the ocean and in turn the weather of the UK. It is believed by some scientists that the thermohaline circulation is slowing down. If it stops then the world will go into another ice age.