Changes in the carbon cycle (big) Flashcards Preview

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Flashcards in Changes in the carbon cycle (big) Deck (22)
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natural variation: wildfires-- what impact did wildfires in Indonesia (1997 and 2003) have?

the fires burnt out of control for months, smoke spread across south east Asia. created a noticeable strike in carbon emissions


what do erupting volcanoes release back into the atmosphere

carbon that has been trapped in the lithosphere for millions of years


how much co2 do volcanoes emit each year

between 130 and 180 million tonnes


how many tonnes of co2 per year are released as a result of burning fossil fuels

30 billion tonnes


what does lava from volcanoes contain that may be damaging

contains silicates which will slowly weather


how can warmer conditions lead to a positive feedback in relation to co2 released (link to permafrost)

melting of permafrost-- releases previously trapped gases which are now being released-- enhances greenhouse gas effect-- positive feedback system leading to further destabilisation of systems


how would colder conditions affect carbon transfer in soils

decomposers would be less effective so carbon transfer would be less effective. soil may also be frozen over- stopped co2 soil transfer


how would colder conditions affect cryospheric stores

more water stored as ice so less is transferred to the oceans. is not evaporated and locks up carbon for a significant length of time.


what percentage of anthropogenic carbon is released by the combustion of fossil fuels (estimated by the IPCC) and what does the remaining percentage come from?

90%, the other 10% comes from land use changes eg deforestation and farming


what percentage of anthropogenic carbon is absorbed by the oceans and atmosphere

50% by vegetation and oceans
50% by the atmosphere


since the 1960s global concentrations of co2 have increased from ... to ....

320 ppm to 400 ppm


how old are the rocks that fossil fuels are extracted from and what impact does this have on the carbon cycle

70-100 million years old. stored carbon is released into the atmosphere, increases the cycling of carbon


what is the main source of carbon emissions on farms

artificial fertilisers


how much methane do cattle produce per year in the US as a result of intensive farming to support the population

approximately 5.5 million tonnes


organic agriculture- carbon sequestration in the soils-- what can it do and how can it help reduce the impact?

organic agriculture can remove the air and sequester 7000 pounds of co2 per acre each year- increases yields in drought years as the additional carbon stored helps it to hold more water


how many hectares of forest are cut down and changed to other land uses each year

13 million hectares


how many acres were lost per year from 2000-2005

7.3 million hectares per year


how do slash and burn techniques affect the carbon cycle

large proportions of above ground biomass are burned (rapidly releasing carbon into the atmosphere)


why does deforestation for farming practices have regional impacts

future absorption of co2 is drastically reduced. the system has now become a carbon source rather than a sink


how do trees and deforestation affect the water cycle as well as the carbon cycle (link to soils)

forest soils become less moist as they have no tree cover. loss of transpiration (returning water back to the atmosphere) when trees are cut down. without trees many former forest lands can turn into barren deserts


globally, cities account for what percentage of anthropogenic co2 emissions



what proportion of people globally live in cities

over half