The Carbon Budget And The Imoacy Of The Carbon Cucle Upon Land Ocean And Atmosphere Inc Global Climate

Question 1

What is carbon budget

Answer 1

Amount of carbon stores and transferred within the carbon cycle

Question 2

How are carbon stores on different geographical scales

Answer 2

Range from 
Individual plant 
Forest 
Lake 
Global biome 
Such as tropical rainforest to global atmosphere

Question 3

How are carbon stores distributed

Answer 3

Unevenly

Some parts of planet covered by oceans and others by land

Some area have vast supplies of fossil fuels but others have none

Question 4

What are the 2 main carbon stores

Answer 4

Lithosphere and hydrosphere

Question 5

Global scale of carbon store

Answer 5

Most of carbon is stored in lithosphere (in sedimentary rocks) or hydrosphere

Small amount stored in atmosphere or biosphere as transfers between these stores = active

Question 6

Effects of inc carbon on land

Land use decisions

Answer 6

more wildfires controlled as threaten human settlement,

inc build up of woody plant material which stores carbon

Fires and deforestation in other locations have inc atmospheric levels

Some farmland in HICs have been replaced by forests

Food imported instead

Trees store more carbon then crops

Agriculture is more intensive - more crops produced from same amount of land. This means carbon is able to be taken up as more CO2 as there are more crops

Question 7

Effect on inc carbon on plants

Answer 7

Carbon taken up by plants has increase since 1960

25% of extra human emissions are removed by plants

More CO2 in atmosphere -> more photosynthesis and more plant growth = carbon fertilisation

But growth limits reach when water of nutrient supplies become exhausted

Higher temp in cold tundra increase rate of deposition of DOM and release more carbon in atmosphere

Inc global temp as a result of more CO2 in atmosphere have inc growing season for plants

But higher temps also mean more evap and evapotranspiration

This req more water which limits additional plant growth and their ability to absorb CO2

Question 8

Consequence of inc level of CO2

Atmosphere

Answer 8

EGE

This is due to human activities esp burning fossil fuels - now over 400ppm

Extra CO2 traps additional heat - warms planet and changes climate

Question 9

Consequences of increased CO2

Ocean acidification

Answer 9

Through diffusion of additional CO2 in oceans

Since 1750, the PH of oceans surface has fallen by 0.1PH units
30% of CO2 releases in atmosphere diffused in ocean

Effect
CO2 in ocean creates carbonic acid which reacts with carbonate ions to form bicarbonate
BUT
Sea creatures eg coral need ions to make shells - so their shells are thinner
Coral reef provide livelihood for 500m people -> sig reef loss leads to fall in biodiversity, threatens coastal communities-> reduced food availability

Acidification can reach point -> ocean becomes corrosive - ecosystems are destroyed - impacts human livelihood

Negative feedback - more acidic oceans —> inc chemical weathering of rocks containing carbon eg limestone -> release more carbonic ions in ocean - restore balance

Question 10

Consequences of increased CO2

Reduced salinity in oceans

Answer 10

As additional freshwater from melting land based ice stores and from additional precipitation dilutes ocean

As water contains less salt = less dense -> ocean circulation is changed as ocean currents such as the Gulf Stream are disrupted

In this case it cannot sink and flow south back to warmer waters of the Caribbean Sea

This means the circular flow is stopped and NW Europe becomes cooler

Water cycle effect on ocean salinity: precipitation of rain or snow -> river run off -> ground water flow to ocean -> freezing of sea water -> evap of sea water

Question 11

Consequence of increased CO2

Warm

Answer 11

Ocean warming means microscopic plants - phytoplankton photosynthesis more effectively - taking in more CO2-
Negative feedback

But in warmer oceans - may kill phytoplankton leading to reduction in amount of CO2 oceans can absorb - so more is retained in atmosphere

Ocean warming also kills symbiotic algae which coral need to grow -> leading to bleaching and eventual death or reefs

Sea level rise predict 0.8-2m by end of century due to melting of ice sheets and glaciers entering ocean, and thermal expansion as warmer water expands and takes up more space

This means sea ice melts reducing amount of light reflective surfaces (ice=white), inc darker absorbant surfaces (blue ocean water) -> further heating = positive feedback