Carbon Cycle Flashcards
Short term carbon changes: volcano eruptions
Eruptions eject CO2 into the atmosphere
Approximately 0.13GtC/Year
Short term carbon changes: Fossil Fuels and Cement production
Burning fossil fuels and extracting them accounts for 80% of human carbon emissions per year
Cement production accounts for 8% of global CO2 emissions
Long term carbon changes: Glacials and Interglacials
- Glacials - Colder Temps, slower decomposition, less photosynthesis, less flow of water, more carbon stored in oceans
- Interglacials - Permafrost thaw releasing CO2, decomposition speeds up adding CO2 to atmosphere, more wildifres releasing CO2 while burning
Impact of rising CO2 levels on the land
- Tundra is warming, increasing rate of decay and methane release
- Increased plant growth means more evapotranspiration and photosynthesis. More CO2 means more plant growth
- Increased wildfires
Impacts of increasing CO2 on the sea
- Ocean Acidification - expected pH drop from 8.05 to 7.65
- Ocean warming - if GHG emissions increase, temp increases 5C
- Melting sea ice - 12.2% retreat per decade
- Increased ocean salinity - 30g/kg results in 71% reduction in sea ice
- Sea level rise - by 2100, rise of 1m expected. Greenlands largest glacier moves 46m a day
What is radiative forcing
The amount by which the Earth’s energy budget is out of balance
In 2023, radiative forcing was 51% higher than 1990
Net human forcing about 2.3 Watts/m2
Carbon Budget
Surplus or defecit of carbon once outputs subtracted from inputs
Future predictions are inaccurate
Arctic Amplification
loss of sea ice, decreasing by up to 1/2 and other positive feedback loops cause the poles to warm up much faster compared to the rest of the world
Surface temps and sea levels by 2100 if emissions increase
Arctic poles increase 11C surface temp with 50% more precipitation
Surface temps and sea levels by 2100 if emissions decrease
Predicted sea level rise or 0.45m
Arctic Circle temp rise of 4C and 20% more precipitations
Positive feedback loops
Wildfires release Co2 by burning, increasing atmospheric CO2 causing rising global temps leading to more wildfires
Ice Albedo
Thawing permafrost releases methane and CO2, increasing atmospheric CO2 and enhancing the GHG effect causing more melt
Negative feedback loops
Increasing CO2 causes more photosynthesis and stimulates plant growth, causing more CO2 taken out of atmosphere
Phytoplankton growth due to warmer temps causes more release of dimethyl sulfide so more cloud formation and blocking, however this increases amount of heat trapped too
Water Vapour
- Composes 50-60% of Earths GHG and clouds 25% of atmosphere
- High clouds retain heat for longer by trapping reflected radiation, lower clouds are thicker and better for reflecting sunlight. As Earth warms, we are likely to get more higher clouds
Oceanic Carbon Inputs
Ocean-atmosphere exchange - CO2 diffuses into oceans depending on water temps, wind speeds and surface conditions
River Discharge - acid rain dissolves surface carbon-bearing rocks (calcium carbonate) and this enters sea in river water
Oceanic Carbon Stores
Deep Currents - downwelling currents take disolved CO2 from surface water to deeper waters and it stays here for centuries
Marine biota - all living things are composed or carbon. Amount of plants and animals living in ocean proves a permanent store of carbon
