ELSS 4 Flashcards
How water and carbon cycles are interdependent (Atmosphere)
Atmosphere- atmospheric CO2 has a greenhouse effect. It is important in photosynthesis by plants. Plants as important carbon stores, extract water from soil and transpire as a part of the water cycle. Water is evaporated from oceans to atmosphere and exchanging CO2
How water and carbon cycles are interdependent (ocean)
Ocean acidity increases when there are more CO2 inputted, there would be lower sea surface temperature (SST)
Atmospheric CO2 level influence: thermal expansion of the ocean, air temperature, melting of ice and glaciers, and sea level
How water and carbon cycles are interdependent (vegetation and soil)
Water availability influence rates of photosynthesis, NPP, transpiration
Temperature and rainfall affect decomposition level and the release of oxygen into the atmosphere
How water and carbon cycles are interdependent (Cryosphere)
CO2 levels in atmosphere determine the intensity of the greenhouse effect and the melting of ice sheets and glaciers as well as the permafrost
Melting exposes more land surfaces absorbing more solar radiation raising temperature further
Permafrost melting increases decomposition
Temperature change impact run off, river flow, and evaporation
Human factors cause changes in availability of water store
Rising demand for water for irrigation, agriculture, and public supply- due to increasing population
Shortages in river and aquifers
E.g Colorado River- surface supply decreases due to water abstraction, evaporation from reservoirs e.g Lake Mead
Quality of freshwater sources decreased due to overextraction of water from aquifer e.g Bangladesh, leading to salt water seeping through in coastal regions- can’t used for irrigation and drinking
Deforestation and Urbanisation- reduce evapotranspiration and precipitation
- increase surface runoff, decrease throughflow and lower water tables
Human factors causing change in availability of carbon stores
Fossil fuels accounts for 84% of world’s primary energy source
Exploitation of coals, oil and natural gas removes billions of tonnes of carbon from geological store- especially due to rapid industrialisation in China and India
8 billion tonnes of carbon is released into atmosphere annually
Deforestation- reduced forest cover by almost 50%- decrease amount stored in biosphere- decreased photosynthesis
Phytoplankton absorbs more than half of the CO2 from burning fossil fuels- much more than forests
Acidification of oceans would threaten this store
Soil stores had been destroyed due to agricultural mismanagement and deforestation
Impact of long term climate change on water cycle
More water vapour would increase global temperature leading to increasing evaporation and precipitation- positive feedback loop
Increased precipitation can increase runoff and higher flood risk
Water vapour is also a source of energy in the atmosphere releasing latent heat(energy required to change state of water) during condensation
More energy in the atmosphere would increase extreme events such as hurricanes and storms
Impact of long term climate change on carbon cycle
Increase temperature, increase rate of decomposition, increase transfer of carbon from pedosphere to atmosphere
Tropical areas, climate change would increase aridity and threaten forests
As forests get replaced by grassland, amount of carbon stored decreases
Higher latitudes, allow more forests to extend towards the poles
Carbon frozen in permafrost of the tundra is released into atmosphere, increases decomposition
Acidification of oceans through absorption of excess CO2 from atmosphere would reduce photosynthesis by phytoplankton- limit capacity for ocean to store carbon
As oceans are too warm, carbon can’t diffuse into it, decrease carbon store in ocean
Management strategies to protect global carbon cycle
Wetland Restoration
Afforestation
Improving agricultural practices
Reducing emissions
Examples of wetlands
Freshwater marshes, salt marshes, peatlands, and mangroves
Importance of wetlands to carbon cycle
6-9% of earth’s land surface
Contain 35% of the terrestrial carbon store
Carbon sink
Can store 3.25 tonnes C/ha/yr
How and why wetlands have been destroyed
Population growth, economic development, and urbanisation
Destruction of wetlands transferred huge amount of carbon and methane into atmosphere
Why will wetland restoration help protect global carbon cycle
Canada prairies provinces lost 70% of wetlands
Restoration programs can store average 3.25 tonnes C/ha/yr
112,000 ha targeted for restoration= take in 364,000 tonnes of carbon per year
Named example of wetland restoration projects
Funding from EU Habitats Directive and International convention on wetlands
China had protected peatlands in upper watershed of Yellow River to conserve environment and reduce flooding
UK- east Cambridgeshire up to 400ha of grade 1 farmland converted back to wetland
How are wetlands restored
Raising water table and re-create waterlogged conditions
Reconnecting floodplains to rivers
Diverting or blocking drainage channel
What is afforestation
Planting trees in deforested areas or in areas that have never been forested
How afforestation protect global carbon cycle
Trees are carbon sinks= reduce atmospheric store of CO2 in long term
Reduces soil erosion and loss of carbon
Named example of afforestation project
China- massive government sponsored afforestation in 1978, called the Green Great Wall- aimed to afforest 400,000km2 by 2050
Used to tackle desertification and land degradation in North China
30,000 km2 planted successfully with non-native species
However, monoculture
What are unsustainable agricultural practices
Over cultivation, overgrazing leading to soil erosion and release of large amount of carbon in atmosphere
Intensive livestock farming- released 100 million tonnes of methane per year
What are the improved agricultural practices
Polyculture- crops grown under trees, protecting soil erosion- less CO2 released into atmosphere
Zero tillage- growing crops without ploughing the soil- reduce risk of erosion
Crop Residues- leaving crop residue (Stems/ leaves) after farming to provide ground cover all year round- protect against soil erosion and drying out
Avoiding use of heavy farm machinery on wet soil- no compacting and less erosion
Improving quality of animal feed, so less feed is converted into methane
What are the international agreements to reduce carbon emissions
IPCC created in 1988 by UNEP
It provides reports on climate change and impacts
Understanding risks caused by human induced climate change
Options for mitigation and adaptation
Kyoto Protocol 1997
Richest countries agreed to legal binding reduction in their CO2 emissions
Developing countries- China/ India which are some of the biggest polluters still need to use for industrialisation
UK had carbon tax on energy used by industries and increased the proportion of electricity provided by renewable sources to 10%. There are also transport policies to cut congestion
Paris Agreement 2015
Aim to reduce global carbon emissions below 60% of 2010 levels by 2050, and keep global warming below 2 degrees per year
Countries set voluntary targets and are not legal binding- countries could go easy on themselves
Rich countries transfer their technology and give fundings for developing countries to reach the target
Cap and Trade
Set limits on emissions and the cap is converted into tradable allowances
Each country is allocated some credits and could trade with other countries if not used
Countries get fined if exceed limit
What are the management strategies to protect global water cycle
Forestry
Water Allocation
Drainage basin planning
What are examples of forestry projects
UN’s REDD programme
World Bank’s Forest Carbon Partnership Facility- fund 50 countries- provide financial incentives to protect and restore forests
Brazil:
Received support from UN, World Bank..
Amazon Regional Protected Area (ARPA) programme covers 10% of Amazon Basin
75% decrease in deforestation
Stabilises regional water cycle
Supports indigenous forests
