Carbon EQ3 - Human threats to global climate system Flashcards
How are carbon and water cycles threatened by human activity?
- climate change
- ocean acidification
- land conversion
What is the importance of the terrestrial biosphere?
Sequesters about a quarter of fossil fuel CO2 emissions annual, directly slowing down global warming
What is the driver of deforestation, how do rates vary globally?
Deforestation is driven by increasing demand for commodity production. By 2015, 30% of all forest cover was completely cleared.
Temperate forests in UK/USA have long history of exploitation, SE Asia has huge rates of deforestation today as well as rainforests in Brazil
What are the implications of deforestation on the carbon cycle, water cycle and soil health?
Carbon = increased release to atmosphere via destruction of carbon sink, less sequestration as removal of primary producers (reduction of NPP)
Water cycle = reduced EVT rates (75% to 25%), more surface run off, reduced interception and infiltration
Soil health = reduction in soil carbon storage and biomass, more erosion/degradation
How does afforestation vary regionally and what are the impacts of this land use change?
Afforestation is more common in HICs, in LICs it tends to be via monocultures of commercial trees (palm oil)
Impacts: beneficial for CO2 sequestration but controversial impacts on landscape character, carbon, water and soil
How does grassland conversion vary regionally and what are the impacts of this land use change?
Grasslands can be used intensively for animals or ploughed up and used as farmlands - more common in temperate grasslands with better agricultural properties
Impacts = soil and ecosystem degradation
What is ocean acidification?
The decreasing pH of the ocean due to their function as a fossil fuel gas sink
What are the impacts of ocean acidification?
INCREASES RISK OF MARINE ECOSYSTEMS REACHING A CRITICAL THRESHOLD OF PERMANENT DAMAGE
- CO2 dissolved into ocean forms carbonic acid, which reacts with carbonate to form bicarbonate
- reduced carbonate ion availability means organisms have thinner, weaker shells
- acidic water dissolves these shells to weaken them
- causing the major functions of ecosystem to collapse (coral bleaching)
- net reef loss
What is ecosystem resilience?
The level of disturbance that ecosystems can cope with while keeping their original state
What is critical threshold?
An abrupt change in an ecological state, potentially due to small environmental changes
What is the enhanced greenhouse effect?
The intensification of the natural greenhouse effect by human activities, primarily through fossil fuel combustion and deforestation, causing global warming
How may climate change impact drought?
Increase frequency of drought due to shifting climate belts (movement of ITCZ/shifts can cause droughts)
What are the implications for human wellbeing from the degradation of the carbon and water cycles?
- forest loss has implications for human health and wellbeing
- altered precipitation patterns/hydrological cycle
- threats to ocean health pose threats to human wellbeing due to the importance of marine food sources and tourism
What is the role of forests in climate regulation?
Help control climate at local, regional and global scales - absorb and store rainfall, add to atmospheric humidity through transpiration.
What are the ecosystem services provided by forests?
- supporting functions: nutrient cycling, soil formation, primary production
- provision of goods: food, freshwater and fuel
- regulation of Earth’s systems: water purification, regulating climate and floods
- cultural value: spiritual, aesthetic, educational, recreational
What is the environment Kuznets curve?
Suggests that societies reach a tipping point, where exploitation changes to more protection
What factors affect the timing of the attitudinal change in Kuznets curve?
- wealth of countries
- rising knowledge of role environment plays in human wellbeing
- aid given to help choices over exploitation
- political systems and enforcement of environmental laws
- participation of locals
- power of TNCs
What does the environmental Kuznets curve look like?
Rising environmental degradation with rising income in development from pre industrial to industrial conditions
Tipping point where rising income reduces environmental impacts due to movement towards a post industrial service economy
What is sustainable management?
The environmentally appropriate, socially beneficial and economically viable use of ecosystems for present and future generations
How do increased temperatures impact evaporation rates?
Increase in evaporation rates, storing more water in the atmosphere
This has implications for precipitation patterns, river regimes and cryosphere and drainage basin water stores
What is the Arctic barometer?
A barometer measures pressure - the Arctic is already showing pressure on its natural systems from anthropogenic influences
What is the Arctic barometer?
A barometer measures pressure - the Arctic is already showing pressure on its natural systems from anthropogenic influences