Module 3: Climate Change and Ecological Overshoot Flashcards
planetary boundaries (3)
- estimate of the boundaries for the biophysical processes that determine the Earth’s capacity for self-regulation
- define the sustainable limits for human existence, and suggested that these boundaries must not be crossed if catastrophic environmental change is to be avoided
- concern whether we understood the Earth system enough to know the real limits to environmental degradation
net primary productivity (NPP)
- estimation of how much of the biomass (living material) produced each year by vegetation is harvested and used by humans
human appropriation of NPP (HANPP) (2)
- through data and modelling, found that humans are appropriating nearly 1/4 of all biomass produced each year by ecosystems
- reduces the energy amount available to other species and influences biodiversity, water flows, carbon flows between vegetation and atmosphere, energy flows within food webs, and provision of ecosystem services
ecological footprint analysis (3)
- standard measure that can be used to related demand for natural resources to the planet’s ability to replenish resources
- results presented as the amount of land and sea area needed to support human populations
- uses existing data to translate human demand on the environment into the area required for the production of food and other goods, together with the absorption of wastes
the tragedy of the commons (2)
- describes an pasture open to common use where each herdsman will try to keep as many cattle as possible to maximize their gain
- gives rise to tragedy: each locked into a system that compels them to increase herd without limit, resulting in environmental degradation that negatively affects everyone
what examples did the author of the tragedy of the commons use to relate it to real world issues (2)
- marine fisheries
- pollution of the environment
what is the overall conclusion of the tragedy of the commons
- over-exploitation of a natural resource is an inevitable consequence of human nature
how could the tragedy of the commons be incorrect/harmful
- due to a misunderstanding of the system, the author mixes up open access and common land
- as a result, companies used this information to seize the highly regulated common land by making the land private and using it for commercialization
carbon stock
- quantity of carbon in a pool (reservoir containing carbon) at a specific time
carbon flux
- transfer of carbon from one carbon pool to another (measured in mass per unit of area and time)
source
- any process or activity that releases greenhouse gas, an aerosol or a precursor of a greenhouse gas in the atmosphere
sink
- any process, activity, or mechanism that removes greenhouse has, an aerosol, or a precursor of a greenhouse gas from the atmosphere
carbon budget
- balance of the exchanges of carbon between carbon pools; examination of this budget will provide info on whether it is acting as a source or a sink
carbon sequestration
- process of increasing the carbon content of a carbon pool other than the atmosphere
what are the main components of the carbon cycle, from smallest to largest (4)
- atmosphere
- land
- ocean
- Earth’s crust
what determines the overall atmospheric CO2 concentration
- the rate of exchanges of atmosphere CO2 with the ocean and terrestrial ecosystems; exchange occurs continuously
carbon cycling in the ocean (3)
- atmospheric CO2 exchanges with oceanic CO2 at the surface through diffusion
- oceanic CO2 reacts to form bicarbonate, allowing oceans to uptake more CO2, but is limited by mineral cation supply from coastal sediment weathering
- concentration of CO2 increases in ocean interior due to two processes: solubility pump ad biological pump
solubility pump (2)
- process where CO2 is transported from upper ocean to interior depending on ocean circulation and mixing where cold, dense waters sink to deep oceans
- the water dissolve and capture carbon before the water masses re-surface again after decades to centuries of years
biological pump (2)
- microscopic organisms (phytoplankton) assimilate CO2 through photosynthesis
- the carbon is fixed in their biomass, 25% sinks to the deep ocean and is oxidized and added to the dissolved carbon concentration
carbon cycling on land (natural) (2)
- CO2 removed from the atmosphere by photosynthesis of plants and stored in organic matter (can be for a long time); about half is released back through respiration
- remainder joins pool of organic matter in soil and eventually returns to atmosphere through soil decomposition (can also take a long time)
carbon cycling on land (human activities) (2)
- combustion of fossil fuels
- land cover change
carbon cycling on land: fossil fuels (2)
- combustion of fossil fuels (coal, oil, natural gas) from million year old organisms as primary energy source
- releases large amounts of CO2 into the atmosphere and alters the natural carbon cycle
carbon cycling on land: land cover change
- land cover change, mainly deforestation, from human population increase and expansion of human settlements
- large areas of native forests cleared and converted into agricultural and urban areas
- as terrestrial carbon storage occurs in forests, land cover changes resulted in net flux of carbon to the atmosphere
how do we know fossil fuel combustion is one of the main anthropogenic sources of CO2 emissions influencing climate change
- it has been proven with evidence: decrease in C13/C12 ratio over time and overall decline in O2 concentration over time
- this could be determined because CO2 emissions from fossil fuel combustion is unique to natural CO2
how do we know land-use change is one of the main anthropogenic sources of CO2 emissions influencing climate change (3)
- CO2 emissions from land-use change is more difficult to calculate and can only be estimated through models
- estimated using book-keeping method that tracks carbon stored in vegetation and soil for each hectare of land cultivated, harvested, or reforested; based on self-reporting data
- due to difficulties calculating CO2 fluxes from land-use change, the literature shows differing total anthropogenic emissions of carbon
land-use change is one of the main anthropogenic sources of CO2 emissions influencing climate change: what two factors give rise to uncertainties (2)
- availability of land-use data, especially related to rate of deforestation
- availability of data on changes in carbon stocks resulting from land management, such as harvesting and burning
what is causing global warming/climate change/changes in Earth as a system
- humans
ecological overshoot (2)
- the phenomenon which occurs when the demands made on a natural ecosystem exceed its regenerative capacity
- occurring right now because of human; our needs surpass the regenerative capacity and resources of a single earth
what are the causal factors to ecological overshoot? (2)
- species/populations have the biological disposition to expand exponentially when possible
- humans have an unparalleled capacity for social learning
causal factors of ecological overshoot: expansion (2)
- species/populations have the biological disposition to expand to fill all accessible habitats AND to use all available resources for continued growth and reproduction
- stock will grow unless a stabilizing feedback mechanism keeps it in check
wha stabilizing feedbacks normally keep populations in check and what does it result in (2)
- population reaches a threshold where it is too big and resource depletion occurs(no more food, space, etc)
- results in loss of infinite growth/ a crash before stabilization of the population size
how are humans bypassing the stabilizing feedbacks that normally act on species populations (4)
- outcompeting other species by modifying the environment
- health care
- social learning
- we construct our reality (laws, politics, economy, etc)
is human population growth an example of a amplifying feedback loop?
- yes: the bigger the population, the more mating that occurs and the more offspring that is produced
causal factors of ecological overshoot: social learning (3)
- we learn from others (both genetically and non-genetically related to us), thus bypassing costly trial-by-error learning
- supports cumulative culture and innovation
- we socially construct our realities and the way we perceive those realities
what is the result of the population growth of humans
- we have a huge (and still growing) capacity for consumption, but Earth did not get any larger; PROBLEM
what fueled the exponential growth of humans
- extensive use of fossil fuels allowed more agriculture mechanization, leading to removal of stabilizing feedbacks due to food and resource abundance
how does technology and efficiency address ecological overshoot
- the though that we can support the growth with efficiency is incorrect; more efficiency will lead to increased consumption due to faster inflow into the stock
symptoms of overshoot: atmospheric CO2 (2)
- increase in atmospheric carbon dioxide and climate change
- 45% increase above pre-industrial levels leads to a change in the chemistry of the ecosphere
symptoms of overshoot: surface temperature
- the average temperature per year is getting warmer
symptoms of overshoot: plunging biodiversity (2)
- human population and economic growth are competitively displacing wild species from their habitats and food sources
- results in extinction and displacement; replacement of wild species with livestock to support humans and room for humans to live
symptoms of overshoot: world energy (2)`
- increase in consumption of all energy types
- positive: renewable energy use is increasing, but this is not the solution if overall energy consumption continues to grow as this will still increase carbon emissions
the boom-bust population cycle (3)
- populations will experience a ‘boom’ when favourable growth conditions occur (humans here right now)
- when nutrients are depleted (unavoidable as we are confined to a finite number of resources on Earth), stabilizing feedbacks will cause the population to go through a ‘bust’
- pattern common to non-human species introduced to a resource-rich system
why can humans avoid the uncontrolled collapse of population (‘bust’) (4)
- high intelligence
- the ability to plan ahead
- the capacity to exercise moral judgement
- empathy/compassion for other people and species
how can humans avoid the uncontrolled collapse of population (‘bust’)
- decrease the overshoot/resource need to be under the carrying capacity of the Earth
project drawdown (2)
- global initiative to rank hundreds of solutions to current climate projections
- aim to show which climate issues are most important to achieve a future point in time when levels of greenhouse gases in the atmosphere stop climbing and start to steadily decline (inflow < outflow)
product footprint
- evaluates life cycle of products and ranks actions
do you personal choices reduce your contribution to climate change
- yes: can be small (upgrading light bulbs, recycling) or large (one less baby, car free life)
why are cars bad for climate change (2)
- the cost to manufacture, refine fuel, run the vehicle, and for maintenance are high; lots of emissions
- more car users take up more space, creating need for more space for roads/parking, creating an increased need to own a car to get to further away places; amplifying feedback loop that requires even more emissions
why is air travel bad for climate change
- a single flight can take up ALL of the suggested yearly emissions (to avoid ecological overshoot) for an individual
why is a plant-based diet good for the environment
- just subbing one plant-based item for a animal-based item can achieve huge emissions reductions and free up cropland
