The carbon cycle Flashcards

Question

Explain Volcanic activity and how it relates to the carbon cycle

Answer 1

- According united states geological survey ' the carbon dioxide released in recent volcanic eruptions has never caused detectable global warming of the atmosphere' - This is because of: - The warming effect of emitted Co2 is counterbalanced by the large amount of sulphur dioxide that is given out. Conversion of sulphur dioxide to sulphuric acid, forms fie droplets, increasing reflection of radiation from sun back into space, cooling earths lower atmosphere. - Amount of Co2 released have not been enough to produce detectable global warming - It has been proposed that intense volcanic release of Co2 in the deep geologic past did cause a large enough increase in atmospheric Co2 to cause a rise in atmospheric temperatures and possible ass extinctions, though scientific debate

Answer 2

- Dead animals or plants turn into fossil fuels following burial - Pressure from multiple layers of sediment leads to anoxic ( oxygen free) environment that allows for decomposition to take place without oxygen - When combined with heat from the earth, the carbon in sugar molecules is rearranged to form other compounds - Animal remains tend to form petroleum (crude oil) - Plant matter more likely to form coal or natural gas - When burnt Co2 and water is released into the atmosphere

Answer 3

- Cement manufacture contributes CO2 to the atmosphere when calcium carbonate is heated, producing lime and CO2 - Estimated cement industry produces around 5 per cent of global anthropogenic CO2 emissions, of which 50 per cent is produced from the chemical process itself, and 40 per cent from burning fuel to power - The amount of cO2 emitted by cement industry is more than 900 kg of CO2 for every 1000 kg of cement produced - In 2013 global CO2 emissions due to fossil fuel and cement production was 36 GtC. - 61 per cent higher than 1990 (Kyoto protocol) and 2.3 per cent higher than 2012. - Emissions dominated by China (28 per cent), USA (14 per cent), and India (7 Per cent). - 2013 CO2 emissions: coal (43), oil (33), gas (18) , cement (5.5), and gas from oil wells (0.6)

Answer 4

Soil Ploughing - When soil ploughed, soil layers invert, air mixes in, and soil microbial activity dramatically increases. - Leads soil organic matter being broken down much faster, carbon lost from soil into atmosphere - Also emissions from tractors increases CO2 levels Main source of Carbon is enteric fermentation - Methane (CH4) is produced by livestock during digestion and released by belches. - In 2011 accounted for 39 per cent of sectors total greenhouse gas outputs.\ Greenhouse gases resulting from biological processes e.g rice paddies - Generate methane make up 10 per cent of total agricultural emissions, while burning of tropical grasslands accounts for 5 per cent According to Food and Agriculture organization (FAO) in 2011, 44 per cent of agriculture- related greenhouse gas outputs occurred in Asia, America (25), Africa (15), Europe (12), and Oceania (4)

Answer 5

- Land use change (mainly deforestation) account up to 30 per cent of anthropogenic Co2 emissions Deforestation - Most driven because of need of extra agricultural land. subsistence farmers (for own) will clear few hectares to feed their families by cutting down trees and 'slash and bur' agriculture - Logging (some illegal), remove forest and also build roads to access more and more remote forests, which leads to further deforestation - Urban sprawl also result of deforestation. - Deforestation can not be intentional e.g wildfires or overgrazing, which could prevent re-establishment of young trees FOA estimated 13 million ha (Roughly equivalent to Greece) are cut down for forests and converted to other land uses every year.

Answer 6

- Planting trees resulted in forests being established or expanded onto abandoned agricultural land. - Reduced net loss of total forest area - In period 1990 to 2000 the worlds is estimated to have suffered a net loss of 8.9 million ha of forest each year - 2000 5to 2005 reduced to an estimated 7.3 million ha/year. - world lost about three per cent of forests in period 1990 to 2005 - At present Losing about 200km2 of forest each day, worlds rainforests could completely vanish in a hundred years at current rate

Answer 7

- Large proportion of above-grounds biomass may be burned, rapidly releasing most of CO2 into atmosphere - Some wood used as wood products, preserved for longer amount of time - Forest clearing also accelerates decay of dead wood, litter and below-ground organic carbon - Fossil fuels are moist, but without the shade from tree cover they quickly dry out. - Trees help maintain water cycle by returning by return water vapour back into atmosphere through transpiration - without trees to fill these roles, many former forestlands quickly become barren deserts

Answer 8

- For first time, over half of worlds population live in urban areas. - As cities grow, land use changes from either natural vegetation or agriculture to one which is built up. - CO2 emissions resulting from energy consumption for transport, industry and domestic use, added to CO2 emitted in cement manufacture required for all buildings and infrastructure have increased. - 2012 cities responsible for around 47 per cent of global carbon emissions. - Even greater concentration can be observed ed for carbon emissions growth from 2012 to 2030 - In total cities are projected to be responsible for 56 per cent of global increase in carbon emissions, with 10 cities contributing 10 per cent of global emissions growth, 28 cities contributing 20 per cent and 193 contributing 50 per cent.

Answer 9

- carbon sequestration involves capturing CO2 from atmosphere and putting it into long-term storage. - Two main types: Geologic sequestration and Terrestrial or biological sequestration - Geological sequestration: CO2 captured in source (e.g power plat or industrial processes) and then injected in liquid form into stores underground. These could be depleted oil and gas reservoirs, and the deep ocean. - Ocean very capable of absorbing much more additional carbon than terrestrial systems simply because of its sheer size. Advantage is that CO2 is literally 'sunk' within weeks or months of being captured from air/water. Once in deep ocean it is in circulation system measured in thousands of years. By the time carbon reaches seabed it has entered the earth's geological cycle. Terrestrial or biological sequestration: Involves the use of plants to capture CO2 from the atmosphere and then store it as carbon in the stems and roots of the plants as well as in soil. - Aim to develop set of land management practices that maximises amount of carbon that remains stored in soil and plant material for long time. increases wildlife. - Disadvantages: forest planted to capture carbon might lose that carbon back to the air in forest fire or if the forest suffers disease or infestation. - land-based sequestration plantations slow growing and require active monitoring and management for the lifetime of the plantation. carbon within those systems is never removed permanently from atmospheric system.