Changes in the carbon cycle (big)

Question 1

natural variation: wildfires– what impact did wildfires in Indonesia (1997 and 2003) have?

Answer 1

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

Question 2

what do erupting volcanoes release back into the atmosphere

Answer 2

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

Question 3

how much co2 do volcanoes emit each year

Answer 3

between 130 and 180 million tonnes

Question 4

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

Answer 4

30 billion tonnes

Question 5

what does lava from volcanoes contain that may be damaging

Answer 5

contains silicates which will slowly weather

Question 6

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

Answer 6

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

Question 7

how would colder conditions affect carbon transfer in soils

Answer 7

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

Question 8

how would colder conditions affect cryospheric stores

Answer 8

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.

Question 9

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?

Answer 9

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

Question 10

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

Answer 10

50% by vegetation and oceans

50% by the atmosphere

Question 11

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

Answer 11

320 ppm to 400 ppm

Question 12

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

Answer 12

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

Question 13

what is the main source of carbon emissions on farms

Answer 13

artificial fertilisers

Question 14

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

Answer 14

approximately 5.5 million tonnes

Question 15

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

Answer 15

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

Question 16

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

Answer 16

13 million hectares

Question 17

how many acres were lost per year from 2000-2005

Answer 17

7.3 million hectares per year

Question 18

how do slash and burn techniques affect the carbon cycle

Answer 18

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

Question 19

why does deforestation for farming practices have regional impacts

Answer 19

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

Question 20

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

Answer 20

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

Question 21

globally, cities account for what percentage of anthropogenic co2 emissions

Answer 21

97%

Question 22

what proportion of people globally live in cities

Answer 22

over half