Carbon Cycle

resp

coal, oil, gas

sedimentary rocks

soil organic carbon

food wars

plants

atmosphere

phytoplankton

food web

shellfish and corals

deep ocean sediments

deep ocean currents

ocean surface

carbon in the hydrosphere

carbon is stored in everything

cryosphere- 0.01,% soil in permafrost

lithosphere- 99.9%, sedimentary rocks, limestone (fossil fuels)

hydrosphere- 0.04%, deep dissolved, inorganic. small surface carbon

biosphere- plants and biological matter, soil.

atmosphere- 0.001%, co2 + methane

inputs:

volcanic eruptions

burning fossil fuels

respiration

ocean loss

decomposition

transfers:

Photosynthesis

→ atmosphere/ biomass

→ energy from the sun. co2 + water = glucose and oxygen

→ plants grow

→ food chain, respiration, decomposition

Combustion

→ burning releases greenhouse gases

Ocean

→ carbon sink taken up by organisms, make limestone shells

→ ocean to the atmosphere also

Respiration

→ carbon from living organisms

→ glucose and oxygen break down to make co2 and water

Decomposition

→ dead biomass goes into the soil

Weathering

→ atmosphere to the hydrosphere

carbon + water = acid rain

chemical weathering on rocks

co2 in water to form calcium carbonate

Sequestration

outputs:

photosynthesis

sequestration

chemical weathering

ocean uptake

greenhouse effect

water and carbon is essential for life

water is present in the atmoshere as water vapor, droplets and

carbon exists as methane and co2.

these are a natural ghg effect, prevents some energy from escaping into space and reflecting it back into earth. earth qould be frozen -18 without it

enhanced gh effect is caused by human activities causing an increase in the concentration of greenhouse gases in the atmosphere. reflects more energy back to the earth

natural processes can change carbon cycle

wildfires:

rapidly transfer large quantities of carbon from biomass to the atmosphere. loss of vegetation decreases photosynthesis. long term it can encourage new plant growth. may have a neutral effect

human impact on carbon cycle:

industrial revolution.

1 hydrocarbon extraction and use (extraction and burning of fossil fuels releases co2)

fuel would say squestered in lithosphere for millions of years

2 deforestation

forests may be cleared for agriculture, logging or developments. clearance reduces size of carbon store.

3 farming practices

animals release co2

ploughing releases co2

rice growth can release methane

co2 from machinery

food is in demand

4. land use changes.

5. change of natural or agricultural urban land causes more carbon in atmosphere. vegetation removed. concrete production releases co2.

carbon budget

difference between inputs and outputs of carbon into a subsystem.

carbon source: releases more carbon than it can absorb (emits carbon)

carbon sink absorbs more carbon.

feedback cycles in carbon cycle

positive:

temperature rise → plant respiration rate increases → co2 in atmosphere increases → greenhouse effectincreases

negative

extra co2 in atmosphere increases → extra co2 causes plants to grow → plants remove and store co2 from atmosphere → co2 in atmosphere reduces

water:

temperature rise → evaporation increases → water vapour in atmosphere increases → greenhouse effect increases.

amount of water vapour in the atmosphere increases causing clouds to form → evaporation increases → temperature falls → increased cloud cover reflects more suns energy back to space.

strategies to stop global warming

individual:

→ use cars less, efficient or electric cars

→ homes can be made more energy efficient- eg, double glazing, insulation

national:

→ reduce reliance on fossil fuels for powering homes

→ investing in renewables

→ afforestation and restoration of forests to increase carbon uptake

→ sustainable developments, public transport

→ carbon capture and storage

global: international treaties to cut co2 emissions and set limits- Kyoto Protocol (1997) / Paris Agreement (2015)

carbon trading schemes limiting emissions by countries and allowing credits to be sold

climate change mitigation efforts

carbon capture and storage

collecting carbon dioxide from emissions and then trapping it underground/water

its expensive and not always viable. unknown environmental umpacts

plantation forests:

the forests act as a sink. if the soft wood is used in non processed products, plantations can be more effective than natural woodland.

carbon is removed to allow more to be captured

space requirement, lack of biodiversity

land use change:

“carbon farming”

replacing crops with better carbon stores such as hay and oats

tilling the soil to prevent erosion and overly aerated microorganisms

“reduce deforestation”

only buy fsc wood and tree products

kyoto protocol clean development mechanism

grassland improvements

develop pedospheric sequesration

less soil erosion, grass pulls o2 into soil

avoid overgrazing

aviation advancement:

fuel efficient routes, avoid circling the airport before landing

minimise towing and taxiing

slower cuising speeds

aircraft to route, ensure all seats are occupied

improve aerodynamics, biofules, ccs, minimise weight

2005 kyoto protocol:

developed countries are the biggest contributors, heavier burden on them:

three mechanisms behind the protocol:

internations emissions trading. each county has a set quoto of emissions. they can trade it with other countries which remains an international limit

clean development mechanism- developed countries can earm more emissions if they implement a successful emission reduced project in a developing country

joint implementation- countries with a cap on the emissions can work together to reduce total emissions. they can earm more emissions

evaluation: generally a success. legally binding meant countries had to adhere

1990-2012 original kyoto protocol parties reduced co2 by 12.5% which was beyond the 2012 target.

this result is largely a result of the collapse of the SOviet Union, decline of russia industry. 42% emissions from USA and CHina- those who did not agree

2009 copenhagen accord

individual personal emission reduction targets for each country.

developing countries notified but not set caps.

developing countries worried the accords would replace kyoto protocol.

accord was not legally binding

these lacked the legally binding so it lacked power.

it did not cap developing countries which are the fastest growing emitters. however it did allow them to freely develop economically

deal unites us, china and other major developing countries for the first time. developed countries will aim to mobalise 100bn py by 2020, to address the needs of developing countries

2015 paris agreement

keep global temperature increase below 2* above pre-industrial

work against climate change and reduce ghg emissions in a way that doesnt threaten food production

paying suitable amounts of money for aid against climate change

not legally binding. each country provides its own targets- developed or otherwise

name and shaming of countries

1st agreement to unite all countries- caused conflict between developed and developing. south africa resulted in loss and damage because the agreement said developing countries would get aid from developed peers

the amazon rainforest

200 billion trees, 15,000 species, 20% of world’s biomass is Carbon

9 countries, 5.5 million km squared. grown and retreated with ice ages

peru, brazil, bolivia, colombia

carbon:

80-120 billion tonnes

carbon sink of 1-3 gigatons/year

above ground, biomass store increases 0.3-0.5% year

rising productivity due to sequestration in atmosphere

2015 study said uptake by forest has halved and ovetaken by fossil fuel emissions from latin America

2 billion tons/ year in 1990, now 1 billion

carbin sink

concentration of co2 in atmosphere leads to increased uptake of trees, live quicker, but die sooner

water

175 thousand cumec discharge into atlantic per day. 15% of all freshwater entering oceans

Rio NEgro, 2nd largest river in terms of flow. 100m deep, 24km wide at mouth of Manaus in Brazil

2,300mm annual reainfall across whole basin. NW can be 6,000 half never reaches ground

48% evaporated and transpired, 30% reaches sea

drivers of change:

deforestation- 19,368 km over 8 years

brazil is the 4th largest climate polluter- 75% from deforestation and land use

59% from amazonion deforestation and burning

slash and burn techniques- humidity decreases in soil to only top metre

more water evaporates, previously held in canopy

albedo (reflectiveness) and temperature increases

soil porosity decreason, more erosion o sitting lakes and rivers

evaporation form shallow cumulus clouds which dont produce rain

salts and organic fibres are transpired by trees- forms condensation nuclei to encourage rainfall. deforestation makes rain less

forests absorb 11% of solar radiation.