theme a - intro to ccs Flashcards
anthropogenic climate change
hockey stick graph for sea ice
theres recent evidence that cc is caused by human activity
extreme events
there has been a change in the probability of extreme events - increased intensity and frequency
- floods
- heatwaves
- droughts
- wildfires
what is the IPCC
international panel for climate change
- represents the consensus view of scientists around the world - published every 8 years
sustainability definition
conserving natural resources for future generations without compromising current needs
what is the great acceleration
growth of the global economic system starting after WW2
rapid economic growth built on:
- cheap energy from ff -
- abundant natural resources
- global expansion of farmland
unequal global consumption
97% of wealth controlled by richest 30%
46% of wealth controlled by richest 0.7%
(global wealth report 2017)
why is resource use unsustainable
there is only consumption by the global wealthy instead of population growth per se
- need vs want society
why does urbanisation increased per capita energy consumption ?
urbanisation increased economic productivity changing resources use
people earn more money and diet changes - eat more meat and empty calories = more food waste
(exception of China and India due to cultural differences)
how does changes in wealth affect food production
people earn more money and diet changes - eat more meat and empty calories = more food waste
(exception of China and India due to cultural differences)
- if diet keeps changing as expected there will be a 70% increase in food calories by 2050
what % of land is used to produce food
50%
- problem due to increasing food demand and how there is still food insecurity
food production and CC
causes 28% of GHG emissions
future demand will drive up emissions (not accounting for changes in the food system) - increase in animal products by 50% predicted
natural climate solutions
- afforestation
- wetland restoration (peat and mangroves)
- managing agricultural systems (biochar, enhancing rot weathering)
what is sustainable intensification of agriculture
increased yields with reduced inputs while improving soil health
what is the challenge for humanity
to break the links between environmental damage and human health, wellbeing and prosperity
(aim to have a low ecological footprint while having a high HDI)
what are SDGs
17 goals adopted by the UN to end poverty, protect the planet and ensure all people enjoy peace and prosperity
- they include targets for all nations to meet
how is each SDG evaluated
using specific targets and measurable indicators
how should resource consumption change
waste
from a linear to a circular economy (reduce, reuse, recycle)
what is a co-benefit between SDG
progress towards the target of one SDG enhances progress toward another
what is a trade off between SDG
progress towards the target of one SDG slows progress towards another
examples of co benefits between SDG
- sustainable consumption and production pattens (12) may be due to a national policy (13)
- ending hunger (2) will reduce preventable deaths of newborns (3) as less malnutrition
examples of trade offs between SDGs
- infrastructure created to give universal access to energy (7) may be damaging to the environment e.g. deforestation may occur (15)
how is land used and valued by people
- human wellbeing
- terrestrial ecosystem services = $75-85 trillion - monetary value
- cultural value
- farming
- tourism
- provision of services - 25-33% of plant production globally is for food, timber and fuel
why is the value of land important
beacuse land area is finite so there is competition between uses
land surface area stats
50% to produce food
25% forestry
land use change
agriculture
8% increase in permeant pastured and a 15% increase in croplands over the last 60 years
what is causing increased land use change
agriculture
- global homogenisation of diets
- restricted global diets
- economic growth
how is global homogenisation of diets changing land use
the range of crops contributing to national food supplies have become more similar in the last 50 years - caused by globalisation and urbanisation leading to dietary transition - increase in energy dense foods (meat,sugars) and major crops (rice, wheat, maize) instead of traditional crops
how is restriction of global diets changing land use
90% of plant calories are from 15 species and 60% rice, wheat, sugar and maize (out of 50,000 edible plant species)
76% of animal protein from milk, eggs, chicken pork and beef (15,000 possible species)
how is economic growth changing agriculture land use
greater wealth increases:
- meat consumption
- food overconsumption
- non communicable disease risk
how has the global supply of food changed in the last 60 years
stats
- supplies in oils and meats have doubled
- food calorie supply increased by 33%
- cereal production increased by 3.4 times
- fertiliser application increased by 9 times
(IPCC)
how is global food supply divided
most land is used to raise livestock or to grow animal feed - only 22% for crops for human consumption
- 40% of crop calories is fed to farm animals
how to achieve net 0
greenhouse gas removal:
- forest restoration
- bioenergy with carbon capture storage
- CCC recommend planting tress and biofuels on pasture land (healthier diets = less meat = more available land for trees)
environmental impacts of land use change
- habitat loss (for timbre or crops/animals) = biodiveristy loss
- overharvesting
- invasive species
- climate change
- global wildlife trade
what is the living plant index and what has it observed
sit monitors the abundance of 20,000 population of 4000 species from 1970 to current day
- global decline in abundance of 69%
impacts of the LPI declining
- loss of carbon from biomass
- plant carbon converted to atmospheric co2 through decomposition and burring
- habitat loss unevenly distributed among ecosystems
- habitat loss due to food production
what causes GHG emissions within the food system
- land use change = 33%
- AFOLU = 1/3 cumulative human co2 emissions
- food miles through global trade (environmental impacts of products evaluated using lice cycle analysis)
- fertilisers
why is the greenhouse effect important
without it the earths average temperature would be 33C cooler
what is net radiative forcing
difference of insolation (sunlight) absorbed by earth and energy energy radiated back to space
how have global temperatures changed over time
snice 1880 0.08 per decade
since 1981 0.18 per decade
2023 was 1.1 warmer then preindustrial temps
the discovery of co2 increase
Keeling tracked atmospheric co2 in 1957 at the south pole and the summit of Mauna Loa volcano Hawaii - proved the correlation
Revelle and Suess wrote the first paper
what is the keeling curve
shows the increase in atmospheric co2 - direct correlation
produced by Charles Keeling
what are the main greenhouse gases and their percentages
co2 - 66%
methane - 16%
nitrous oxide - 6%
chlorofluorocarbons - 8%
what is global warming potential
compares the integrated radiative forcing over a specific period
(a measure of how much energy the emissions of one ton of a gas will absorb over a given period of time)
what are the main anthropogenic sources of co2
electricity and heat (40%)
transport (21%)
manufacturing and construction (16%)
what are the main anthropogenic sources of methane
agriculture (42%)
fugitive emissions (38%)
waste (18%)
what are the main sources of nitrous oxide
agriculture (82%) - due to fertilisers in soil
industry (9%)
waste (5%)
what are the main anthropogenic sources of GHGs
electricity and heat (31%)
transport (17%)
manufacturing and construction (12%)
agriculture (11%)
why are we getting more extreme events
- increase in mean temperature - causing bell curve to shift right
- increase in variance (unusual temps becoming more common) - flattens bell curve
what is happening to global extreme heat
- local record breaking temperatures are 6x more frequent
- 80% increase in extreme heat is due to cc
are trends (increased temp) and extremes linked?
heatwaves - yes - dryer=hotter
droughts - yes - hotter=evaporation
precipitation - yes - warm air hold more moisture
storms - yes - warmer sea surface temp = TS
ecological implications of CC
tensioned landscapes
- passed lethal thresholds
- tensioned landscapes more common - better adapted species moving in to communities with changed conditions
- over time tensions grow as species become less well suited to their environment
- extreme evets cut the tension as can kill all species present allowing new organisms to move in
- results with new balances under a new trend climatic condition
what are extremes
climatically - 95 percentile
ecologically - abruptness (magnitude and duration of an event relative to the lifespan of the organism)
what is an ecosystem
a physical area covered by groups of organisms experiencing similar environmental conditions
what is a biome
areas of vegetation characterized by the same life form - associated with particular climatic and soil conditions
components of ecosystems
communities of organisms and abiotic components that are linked bu processes of energy transfer and material cycling
- may be classified using taxonomy
biotic interactions
trophic
- autotrophs - primary producers
- heterotrophs - consumers
- saprotrophs - decomposers
symbiotic
- mutualism - pollinators, mycorrhizas
- parasitism
- predation
- competition
abiotic interactions
primary production - determines growth, nutrient demands, mortality and turnover
water ralations rate and efficiency of water use tolerance of drought conditions, storage capacity
ecosystem structure
who lives there and what are their traits
- biodiveristy
- biomass
- adaptations to environment
ecosystem functions
what processes operate and how are they controlled
- carbon exchange with atmosphere
- hydrological cycle
- energy exchange
- biotic interactions
overcome the problem that ecosystems are complex
observation of the whole ecosystem needed
- tall towers built over forest with sensors that measure many different factors
role of ecosystems in climate change and sustainability
exert important influences via their effects on land surface
processes of energy transfer
- trophic pyramid - how energy moves through the food chain
- photosynthesis 5% efficient
- land surface energy balance, shortwave solar (high) energy is received to earth and is lost by reflection, latent heat and sensible heat
effect of vegetation on climate
- influences albedo
- reflection depends on wavelength
- controls evaporation - trees use move water than grass etc
- transpiration through plant accounts for 85% of terrestrial evaporation
- evaporation accounts for 50% of solar energy absorbed at the earths surface
what is material cycling
organisms (especially plants) control the cycling of materials (water, N, C, P) with the soil and atmosphere
biological sources of co2
vegetation (respiration)
soil processes
biological sources of methane
soil processes
ruminant livestock
biological sources of nitrous oxide
soil processes
livestock waste
mitigation
why are ecosystems important
carbon sinks
flood mitigation
heatwave mitigation
minimise soil erosion
why is it important to study agricultural ecosystems
studying anthropogenic crop soil systems as ecosystems is fundamental for sustainable ecosystems
