Balanced Carbon Cycle Crucial for Earth Systems, Disrupted by Human Activities (Edexcel A-Level Geography): Revision Notes
📚 Revision Notes
Balanced Carbon Cycle Crucial for Earth Systems, Disrupted by Human Activities
Carbon Forcing → 🔗The influences that cause changes to the Earth's climate system altering Earth's radiative equilibrium, forcing temps to rise or fall
Carbon Fertilisation → 🔗The extra growth of plants due to the presence of more atmospheric CO2 and ∴ more Carbon
Ocean Acidification → 🔗The dissolving of CO2 in the ocean causes carbonic acid to form
↳ A balanced carbon cycle is important to sustain other systems
- Plays a key role in regulation of the Earth's global temperature by controlling amount of CO2 in atmosphere
Natural Greenhouse Effect
↳ The earth has a natural temperature-control system that relies on greenhouse gases
- The conc. of atmospheric carbon strongly influences the greenhouse effect Three Major Greenhouse Gases
- Carbon dioxide
- Methane
- Nitrous oxide (nitrogen cycle)
- Heat energy from the sun warms the planet, but without the atmospheric greenhouse gases, this would not be enough to support life
- The heat energy that is reflected back towards space from the earth's surface and lower atmosphere has a relatively long wavelength, so it has difficulty travelling through denser gases and is absorbed by them
- Without this, the avg temp of the Earth would be 21C cooler Distribution of Temperature and Precipitation
↳ Greenhouse gases ↑ temps, which affects precipitation patterns
Ocean and Terrestrial Photosynthesis
↳ Takes place on land and in ocean (wherever plants are present)
- Regulates the composition of the atmosphere by balancing O2 and CO2
Soil Health and Photosynthesis
Photosynthesis
- Regulates the NPP of veg around the world and ∴ plays a role in regulating atmospheric CO2 levels and global temps
- NPP highest in tropical rainforest and warm shallow oceans
- NPP is lowest in the arid and tundra areas
Soil Health
- Amount of carbon in a soil determines its health (productivity)
- Soil health is determined by the net carbon balance between inputs and outputs
- There is a strong positive relationship between soil health and ecosystem productivity
Fossil Fuel Combustion
- People → Influenced the carbon cycle where fossil fuels have been mined and subsequently burnt
- CO2 is a greenhouse gas that enhances atmospheric heating and contributes to climate change
Relationships Between the Water Cycle, Carbon Cycle and Climate Change
- Changes to the carbon cycle are the causes of climate change, through the combination of the greenhouse effect
- Climate change is having an effect on the water cycle, such as increased EVT and precipitation
- Climate change has an effect on the carbon cycle as more CO2 released from permafrost as ↑ temp causes melting
- Longer plants growing seasons ∴ plants need more water
- Higher temps cause soil baking which causes an ↑ in the rate carbon seeps out of the soil in some places
- Melting of permafrost releases CH4 and CO2 due to the decaying of organic matter & carbon
Further Implications of Climate Change
- More extreme weather events
- Melting of ice caps and glaciers causes rising sea level and flooding coastal cities
- Declining ecosystem biodiversity, ocean acidification and coral bleaching
- CO2 causes ↑ temps ∴ expending the growing season & ↑ in humidity = additional plants growth
Climate Predictions
| Global | Regional |
|---|---|
| ● General temps will ↑ ● Sudden shifts in weather patterns ● More extreme weather events ● Rising mean sea level | ● Some regions will become warmer and drier and others wetter ● Some regions will have less snow and more rain ● Storm surges may ↑ |
Implications for Ecosystems
↳ Help to regulate carbon and hydrological cycles
- Marine organisms are threatened w/ progressively lower O2 rates and magnitudes of ocean acidification
- Rising temperature may alter the foundation of the food chain
- Majority of species will be negatively affected by climate change but some will benefit
Implications for the Hydrological Cycle
↳ The hydrological cycle's flows and stores are vulnerable to global warming
- The most likely implication will be increased temperatures and evaporation rates therefore leading to more moisture circulating around the cycle