Carbon 6.3 Flashcards

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1
Q

the role of carbon is the natural greenhouse effect

A
  • Solar energy enters the atmosphere
  • Only a little short-wave radiation is absorbed in the atmosphere
  • As this short-wave energy passes through the atmosphere it might hit dust particles or water droplets and be scattered or reflected
  • Solar energy heats the Earth’s surface, which then radiates long-wave heat energy into the atmosphere
  • Some long wave energy escapes into space
  • Long-wave energy is quite easily absorbed by naturally occurring greenhouse gases in the atmosphere. Of these, carbon dioxide is by far the most abundant
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2
Q

Nitrous oxide

A
  • From car exhausts
  • Power stations
  • Fertilisers
  • 3% of all gases
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3
Q

Carbon dioxide

A
  • Burning of fossil fuels such as coal, oil and gas for domestic, industrial and transport use
  • 89% of all gases
  • Largest radiative forcing affect
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4
Q

methane

A
  • Released from waste dumps, farms and rice paddy fields
  • 21 times more powerful
  • 7% of all gases
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5
Q

halo carbons

A
  • These are the most damaging
  • Only 1% but 3000 times more powerful
  • From aerosols and fridges
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6
Q

Why is the heating uneven across the earth?

A
  • Angle of the incoming radiation is overheard
  • Higher concentration and more efficient heating at the equator
  • Same amount of radiation has to heat a larger area due to angle it hits poles
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7
Q

What other factors affect the amount of solar energy that is absorbed at the earth’s surface?

A

-the albedo effect

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8
Q

What processes occur to reduce the temperature extremes at the equator and the poles?

A
  • Atmospheric circulation

- Ocean currents

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9
Q

distribution of temperature around the world

A
  • The amount of solar energy (solar insolation) reaching the Earth’s surface varies at different locations – which then influences the temperature
  • The angle of the sun’s rays makes solar insolation intense at the Equator, but dispersed at a wide area at the Poles
  • Different characteristics of the earth’s surface also affects how much heat is absorbed and reflected (albedo) - snow reflects heat and dark forests absorb it
  • Heat is distributed around the globe by air movement caused by both pressure differences and ocean currents.
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10
Q

distribution of precipitation around the world

A
  • The heating of the earth’s atmosphere and surface controls the temperature, pressure, movement and moisture content of the air
  • Warm air rises and cools leading water vapour to condense and clouds to form
  • Solar radiation is more intense over the equator, so convection and low-pressure systems dominate here – precipitation is high
  • Air pressure rises around 30 degrees north and south, precipitation decreases
  • Mid latitudes are where air masses of different characteristics meet and low-pressure systems bring rainfall
  • Near the poles, precipitation falls as the air cools further and is dense and dry
  • Regional and seasonal variates occur – due to the effects of relief and the migration of global pressure patterns and wind systems as the sun moves north and south
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11
Q

Why has the concentration of methane increased?

A

From 1984, methane concentration has gradually increased from 1625 to 1850 in 2020. One reason for this increase is due to higher demand for farming products for food, this is caused by the increase in middle class in lots of emerging countries so therefore lots of land is converted to rice paddy fields which creates a loss of a carbon sink.

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12
Q

Photosynthesis

A

• Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesise (extract) nutrients from carbon dioxide and water.

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13
Q

why is photosynthesis important?

A

-Photosynthesis by terrestrial (land) and oceanic organisms plays an essential role in keeping CO2 levels relatively constant and thereby helping to regulate the Earth’s temperature.

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14
Q

What is NPP?

A

Net primary productivity – a measure of the rate of photosynthesis in an ecosystem and therefore gives a measure of the size of the carbon sink

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15
Q

What is app controlled by?

A

– is controlled by climate and availability of nutrients

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16
Q

threats for tundra

A

rising temperatures

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17
Q

threats for boreal forest

A

logging

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18
Q

threats for temperate deciduous forest

A

logging, development (urbanisation, industrialisation and agriculture)

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19
Q

threats for temperate grassland

A

conversion to arable and pastoral farming

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20
Q

threats for savannah grassland

A

conversion to arable and pastoral farming

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21
Q

threats for desert and semi desert scrub

A

fire

22
Q

threats for tropical rainforests

A

deforestation for logging, mining and HEP

23
Q

threats for swamps and marshes

A

drainage and conversion to agriculture

24
Q

threats for open ocean

A

ocean acidification, rising temperatures

25
Q

threats for coral reefs

A

ocean acidification, rising temperatures

26
Q

How does organic carbon get into the soil?

A
  • Organic carbon is added to soil when plants and animals die and excrete
  • This is broken down by decomposers to produce humus (nutrient rich broken down organic matter ideal for plant growth) and eventually released as CO2 when fully broken down
27
Q

Reasons why having a high organic carbon content is important for keeping the soil healthy

A
  • Encourages biodiversity (earthworms and microbes to help decompose)
  • Provides basis for plant growth (nutrients)
  • Promotes infiltration and moisture retention through provision of pore spaces
  • Maintains a strong structure which is less likely to be eroded away
  • Enhance plant growth
  • Supports micro-organisms that maintain the nutrient cycle
28
Q

The amount of stored carbon depends on the system:

A
  • The amount of organic matter stored within the soil = inputs (Plant litter and animal waste) – outputs (decomposition, erosion and uptake in plant growth)
  • The size of the store depends on different biomes
29
Q

What is the carbon balance controlled by?

A

Carbon inputs from photosynthesis and carbon losses by respiration

30
Q

Characteristics of healthy soil:

A
  • Dark, crumbly and porous
  • Contain many worms and other organisms
  • Provide air, water and nutrients for micro-organisms and plants to thrive
  • Contain more carbon or organic matter
  • Sequester carbon
  • Improve resilience to wetter weather, because they enable infiltration and percolation of water which reduces soil erosion and flood risk
  • Retain moisture, which regulates soil temperature during heatwaves and reduces the effects of droughts
31
Q

soil in the northern hemisphere

A
  • Winter organic decay increases the amount of CO2
  • Springs renewed plant growth causes a reduction as new plant growth absorbs it
  • If winter becomes shorter, it’s possible that less CO2 will be released
  • Climate change may also create a natural response and that more CO2 will be absorbed which will alter the balance
32
Q

carbon pathway

A

refers to the flows/fluxes of carbon in the cycle (e.g., flowing from atmospheric/gaseous carbon to organic carbon in photosynthesis)

33
Q

balanced carbon cycle

A

– the carbon cycle is said to be in balance/equilibrium if the sources of atmospheric carbon are balanced with the sinks

34
Q

is the carbon balanced now?

A

The carbon cycle was balanced until the industrial revolution when sources started to increase, and sinks stayed constant

35
Q

main human activities impacting the climate

A
  • Fossil fuel combustion

- Deforestation

36
Q

positive feedback

A

when a process or event results in an amplification of an effect

37
Q

negative feedback

A

when a process or event results in a reduction of an effect

38
Q

Pathway 1 for the climate

A
  • Shrubs and trees invade the Arctic landscape and store more carbon than is being released into the atmosphere.
  • A short-term balance is reached – negative feedback
39
Q

pathway 2 for the climate

A
  • The decomposition of plant material in wet souls reduces carbon stores by releasing more CO2 and CH4 into the atmosphere
  • Increased greenhouse gases reinforce global warming in the longer term – positive feedback
  • Scientists believe that this will add as much carbon to the atmosphere each year as all of the land use changes in the rest of the world combines
40
Q

what is the debate about carbon pathways?

A
  • Previously, frozen stores of carbon meant slow pathways
  • Now increased thawing has accelerated the process of carbon releases and a faster pathway is emerging
  • In theory, constant levels of CO2 in the atmosphere are maintained if photosynthesis keeps pace with the release of greenhouse gases
  • However, increased thawing means that water and methane are also being released as ancient vegetation decomposes and trapped gases seep to the surface
  • Plants and micro-organisms grow faster than before and respire CO2
41
Q

Implications for climate

-oceanic thermohaline

A

oceanic thermohaline circulation may weaken and shut down

42
Q

Implications for the climate

-depressions

A

-extra tropical low pressure systems (depressions) will move northwards

43
Q

Implications for the climate

-dry areas

A
  • the Sahel, mediterranean, South Africa and generally in the topics will become drier
  • cause 20-30% reduction is water availability
44
Q

Implications for the climate

-ocean acidification

A

ocean acidification and increasing temperatures could affect phytoplankton and its ability to sequester carbon as well as affecting the rest of the food web

45
Q

Implications for the climate

-coral reefs

A

80% of coral reefs could be lost through coral bleaching and ocean acidification

46
Q

Implications for the climate

-arctic temperatures

A

-increasing at double the rate (arctic amplification) with a reduction in sea ice, ablation of glaciers and reduction in snow cover

47
Q

Implications on the hydrological cycle

-river discharge

A

-river discharge will reduce from glacier fed rivers as glaciers recede

48
Q

Implications on the hydrological cycle

-precipitation

A

-rivers will dry up in regions where precipitation is reduced or less effective because of higher evaporation rates

49
Q

Implications of ecosystems

-habitats

A

habitats short poleward or to higher altitudes resulting in biodiversity reducing as some species struggle to migrate

50
Q

Implications of ecosystems

-shifting temperatures

A

ocean and coastal bird habitats are threatened by shifting temperatures and salt water encroachment (pacific golden plover)