interrelationships between the carbon and water cycles and mitigating climate change

how can deforestation and rainfall affect the stores of carbon in the tropical rainforest 

• rainfall that forms over intact tropical rainforests may fall over deforested land, causing soil erosion.

• if soil and ash flows into rivers it increases carbon content of rivers

due to deforestation, how can the process of water leaving the rainforest system affect an area

• water leaves the rainforest cycle as an output through streamflow due to reduced interception and increased surface runoff 

• this could cause desertification, potentially reducing overall evapotranspiration and precipitation in these areas

how could climate change affect the rainforest climate 

• high temperatures could lead to forest migration as some habitats become unsuitable for trees as the climate changes, causing desertification in these areas.

• the desertification further reduces evapotranspiration and the likelihood of rainfall

how can deforestation affect rainfall in the intact forest

• there is reduced rainfall in the intact forest due to less evapotranspiration of trees in the deforested area

• this could cause drought periods and the intact rainforest to deteriorate

what is peatland

an expanse of waterlogged, acidic soil and peat (partially decayed organic matter)

it is the largest terrestrial carbon store

what event can affect carbon storage in peatland

• peatlands is drained by large channels which reduces its water storage

• converted into highly productive farmland due to the fertile soils

• organic peat matter is not longer preserved underwater and decomposes quickly, releasing co2 into the atmosphere

• weathering and erosion increase, which speeds up decomposition.

how can the effect of drainage ditches be fixed

• blocking notches helps increase soil water storage and decrease runoff

• raises the water table and decreases flood risk

• carbon storage is increases, as peat is made up of carbon and water

• wildlife benefit from wetter conditions

what strategies can be used to mitigate climate change

• setting targets to reduce greenhouse gas emissions

• switching to renewable sources of energy

• ‘capturing’ carbon emissions and/or storing or burying them (sequestration)

what was the Paris Climate Deal (COP21)

• aims to limit the increase of global temperatures to 2*C above pre-industrial levels

• support for developing countries

• meet every 5 years to review and improve goals

what is the Climate Change Act 2008 UK

• legally binding target for the UK to reduce GHG emissions by 80% of 1990 levels by 2050

• created national carbon budgets

give some examples of mitigating climate change on a local scale

• improve home insulation

• recycling

• using energy more wisely and use of smart meters

• using public transport

how many times greater than the atmospheric store is the ocean store of carbon

50 x

what is the biological pump

• phytoplankton (microscopic plants) and other marine animals convert CO2 into organic matter through photosynthesis

• this transfers carbon from the surface to the deep ocean stores

• as the organisms die, their dead cells and shells sink into the deep waters

• the decay of the organisms releases carbon dioxide into the deep water

• (overall, carbon is transferred from the atmosphere to the deep ocean stores)

what is the physical pump

1. downwelling occurs in parts of the ocean where cold, denser water sinks

2. these currents bring dissolved carbon dioxide (through diffusion) down deep into the ocean

3. once there, it moves in deep ocean currents, staying there for hundreds of years

4. eventually, these deep ocean currents (part of the thermohaline circulation) return to the surface by upwelling

5. the cold deep ocean water warms as it rises towards the ocean surface and some dissolved carbon dioxide is released (through diffusion) back into the atmosphere

what is the carbonate pump

• when organisms die and start to sink, many shells dissolve before they reach the ocean floor

• this forms carbonates which are stored in the upper ocean, and some organisms use them to make shells or skeletons

• some sediments sinks to the ocean floor and forms the sea bed sediment store

• overtime, the carbon is transformed into rocks such as limestone 

describe chemical weathering

• the carbon dioxide in the atmosphere dissolves in rainwater to create a weak carbonic acid, which, once in contact with rocks, slowly dissolves them.

• the atmospheric carbon is then transported by rivers into the oceans, where it is trapped for thousands of years in marine sediments or corals.