Greenhouse Gases Flashcards
what is the IPCC
intergovernmental panel for climate change
it is a intergovernmental boudy of the UN providing the world with objective, scientific basis of the risk of human-induced climate change, its natural, political and economic impacts and risks.
what is the UNFCCC
united nations framework convention on climate change.
it seeks for the stabilisation of GHG concentrations in the atmosphere at a level taht would prevent dangerous anthropogenic human-induced interference with the earths climate system.
what is snowball earth?
a cliamte disaster triggered by the evolution of oxygenic photosynthesis
what is the Dansgaard-Oeschger cycle?
rapid climate change during the last glaciation
what is the main cause of climate change?
Greenhouse effect
what is the greenhouse effect?
sunlight passes through the atmosphere and warms the surface of the earth. most escapes to outer space and cools the earth, but some IR is trapped by gases in the air, these reducing cooling.
what is the history of global greenhouse gases?
the insulating influence is importnat. historical records of the concentrations of 5 atmospheric gases important for global warming that occur in the troposphere.
what are the 6 main greenhouse gases?
CO2, CH4, N2O, Ozone O3, CF4 and CFC-12
what is the contribution to greenhouse effect of each gas, relative to CO2?
CO2 - 1 CH4 - 34 N2O - 298 Ozone - 2000 CF4 - 7,350 CFC-12 - 15000
what is the word equation for radiative forcing?
incoming energy - outgoing energy = radiative forcing
which year is RF ecpressed relative from?
1750
what are the other processes which has caused radiative forcing to warm?
greenhouse gas use, tropospheric ozone, aerosols, in terms of fossil fuels burning and mineral dust, aviating-indusced clouds and solar
what are the processes which have caused radiative forcing to cool?
stratospheric ozone, sulfate, fossil fuel, burnign of organic carbon, biomass burning, minteral dust, tropospheric aerosol indirect effect, and land use (albedo)
what are the major soil-bourne greenhouse gases?
CO2, CH4 and N2O
which are the 3 contributors to the greenhouse effect?
CO2, Methane and water vapour
what percentage of contribution to the greenhouse effect is water vapour?
36-40%
what does GWP stand for
global warming potential
what is global warming potential?
comparison of how much heat is trapped relative to CO2
what does GTP stand for
global temperature change potential
what is global tempearture change potential?
how much surface temparature change relative to CO2
what is the lifetime of CH4?
12.4 years in the atmosphere
what was the paris agreement?
most severe impacts prevented by mimiting warming to minus 2 degrees and preferably 1.5
190 of 197 particles have ratified the agreement
each country submits “Intended Nationally Determined Contributions (INDC) that would constitute the core mitigation commitments.
what is INDC
“Intended Nationally Determined Contributions”
what is climate geoengineering?
deliberately releasing things into the atmosphere to control it
what are 6 examples of climate geoengineering
using satellites in space
injecting aerosols into the stratosphere
brightening marine clouds
making the ocean surface more reflective
growing more reflective plants
whitening roofs and other built structures
why is climate geoengineering controversial?
much better to address the cause rather the effect
inherent risks
risks of unintended consequences
efficacy difficult to determine
who would regulate their deployment?
what does NET stand for?
Negative emission technologies
what is the climate change causal chain?
fossil energy system > release of CO2 emissions > heat trapping greenhouse gases, and earths system reflectivity > impact of climate on human and natural systems
what are the response options for negative emission technologies?
decarbonise and reduce energy demand industrial CO2 management CO2 removal in terms of mitigation solar radiation management in terms of adaptation prevention and minimise climate damages
what does CCM stand for
CO2 control management
what are examples of negative emission technologies?
afforestation and reforestation
soil carbon sequestration
biochar
bioenergy with carbon capture and storage
direct air capture
enhanced weathering and ocean alkalisation
ocean fertilisation
how would afforestation and reforestation help?
in terms of agroforestry, they would help boreal, temperate and tropical areas, with implementation of agricultural practices and livestock practical
it has reversible permanence and has a decrease in cost with an increase in potential
what are the positive side effects of afforestation and reforestation?
better soil quality
what are the negative side effects of afforestation and reforestation?
albedo, biodiversity and food security
how would bioenergy carbon capture and storage help as a negative emissions technology?
crop residue, dedicated crops and marginal dedicated crops
it has a stable permanence and has an increase in potential and cost after 2050
what are the positive side effects of bioenergy carbon capture and storage ?
there are none
what are the negative side effects of bioenergy carbon capture and storage ?
biodiversity, food secutiry, traces of GHG’s, and air pollution
how would biochar help as a negative emissions technology?
crop residue, dedicated crops and marginal dedicated crops
stable permanenece and cost will decrease as well as potential after 2050
what are the positive side effects of Biochar?
soil quality and traces of GHG
what are the negative side effects of Biochar?
food security
how would enhanced weathering help as a negative emissions technology?
silicate rocks, carbonate rocks all used
limited mineral production however.
stable permanence and cost will decrease, and potential increase after 2050
what are the positive side effects of enhanced weathering?
soil quality
what are the negative side effects of enhanced weathering?
ground and water pollution
air pollution
mining and extraction needed
how would direct air capture help as a negative emissions technology?
suspended amines and wet calcination
deployed in niche markets, and permanence is stable. potential increase and cost decrease after 3050
what are the positive side effects of direct air capture ?
no one is sure
what are the negative side effects of direct air capture ?
no one is sure
how would ocean fertilisation help as a negative emissions technology?
10s of small demonstrations
stable but UNCERTAIN
can be done using iron fertilisation, N and P fertilisation or enhanced upwelling
what are the negative side effects of ocean fertilisation?
ecosystem changes, traces of GHG’s and mining and extraction needed
what are the positive side effects of ocean fertilisation?
there are none
how would soil carbon sequestration help as a negative emissions technology?
using agricultural practices and livestock practices
reversible permanence and ready for large scale deployment
what are the positive side effects of soil carbon sequestration?
food security and soil quality
what are the negative side effects of soil carbon sequestration?
traces of GHG’s
what are the 8 sources of atmospheric methane?
landfills biomass burning fossil fuels gas hydrates termites ruminants natural wetlands flooded rice fields
what is methanogenesis
anaerobes living close to the thermodynamic limit of life
what are the 4 processes needed for polysaccharides to be turned into CH4 and CO2?
hydroloysis
acidogenesis
acetogenesis
methanogenesis
which archaea aid methanogenesis?
methanogens
what propoerties do methaogens have?
they are anaerobes, and they are either hydrogenotropic or acetoclastic
where does methanogeneis occur?
occurs in flooded soils and other environments with a low redox potential
what are the processes which worsen the atmosphere?
livestock rice cultivation landfulls and waste fossil fuels biomass burning
what is methane hydrate, and what is its concern?
clathrate. it is a solid where methane is trapped in frozen water. if the temperature goes up, this will be released into the atmosphere, then increasing methane content in the air
its also in permafrost
how likely is the release of CH4 hydrate?
it is considered unlikely.
what is aerobic methanotrophs
the key enzyme for methane oxides
what is the amount of biological CH4 oxidation per year?
around 800 Tg y-1
what is the chemical equation for the aerobic carbon cycle?
CH4 + 2O2 > CO2 + 2H2O
what is the chemical equation for the anaerobic carbon cycle?
CH4 + SO4-2 or NO3^- > CO2 + H2S or N2
what percetnrage of anthropogenic CO2 equvanet emissions are short term?
1.3%
how many reserviours are larger than 0.01 ha in 2011?
16.7
how many large dams are in construction?
857
what are hydroelectric dam?
clean energy dams, which uses water to hold energy
what is the estimation of PgC in soil?
1500-2400
what services are provided by soil?
biomass recycling systems.
source of nutrients
why are soils a biomass recycling system?
the soils are natures recycling system, and return biomass and nutrients to forms that can be used for the next generation of life
why do soils serve to prupose of the source of nutrients?
soils support the growth of higher plants by providing a medium for plant roots and supplying nutrients that are essential for plant biomass and metabolism
soil properties are often in large part responsible for the types, diversity and biomass of vegetation and microorganisms in ecosystems, and indirectly the number of animals that the vegetation can support
what kind of biomass and biodiversity are soils a home for?
microbes, fungal hyphae, menatodes, fungi, nematodes, mites, springtails
what is soil?
hummus and mineral components
what is humus?
carbon that has resisted degradation
it very slowly decomposes and provides soil with its dark colour
what is the horizon of soil?
this is the top layer of soil, it is also the most biologically active layer, with higher organic matter and nutrients
what is critical in soil chemistry for nutrient retention?
cation exchange capacity is crticial for nutrient retention
what are colloids?
they are the smallest particles of clay or humus, which are chemically active.
it is mainly negatively charged, with cation exchanged capacity with soil solution and plant roots.
what is CEC
cation exchange capacity
why is soil fertility important?
for the ability to sustain plants
what 7 aspects are important for soil fertility?
nutrient abundance and balance bioavailable phosphorus type of clay pH toxic elements salinity microbes
why does topography affect water drainage?
upland soiul and wetland soil are different. wetland soil is often partially flooded and have unique vegetation tolerant of anoxic conditions
what are the two biomass of roots that are of importance?
natural prairies and short roots of cultivated grains
what do forest soils uptake?
CO2 uptake and storage through photosynthesis and primary production
what do forest soils release/output?
CO2 effluent through autotrophic respiration
CO2 efflux through heterotrophic respiration
CH4 uptake by methane oxidising soil bacteria
N2O efflux through microbial nitrification and denitrification processes
are forest soils CO2 sinks?
yes, but not over long term. peatlands are the only terrestrial ecosystem that have a greater NPP than decomposition over the long term
what fraction of total soil carbon does peatlands hold globally?
1/3
what percentage of the earths cover does peatlands hold?
3%
what percentrage of atmospheric CH4 does peatlands emit?
10%
what does a high water-table result in?
anoxia, slow decomposition, but greater CH4 emissions
why does Sphagnum peat decompose slowly?
it is flooded, which makes it anoxic/anaerobic, it is acidic and it is nutrient poor
what percentage of land which is used for agriculture, affected by soil degradation?
52%
how many hectares is lost to drought and desertification?
12 million
how does physical degradation and erosion impact soils?
bare soils are vulnerable eto wind and water erosion.
due to hoof traffic with overgrazing, soils structure is further degraded, as well as tillage and very heavy equipment being used
what is the American dust bowl?
1930’s, native grasses with deep roots help keep moisture in the ground and stabilise the soil.
the farmers removed native grass and planted wheat. the ploughing and also livestock disturbed the soil structure. and the soils became highly susceptible to wind erosion.
what 4 impacts occur from chemical degradation?
depletion - of organic matter and nutrients
contamination - which chemical pollutants
salinization - in dry areas
desertification - only occurs in arid, semi-arid and dry sub-humid areas.
what does acid rain cause?
it causes flooding of cation exchange sites on solid colloids with protons (H+)
how does acidification cause chemical degradation in soils?
it displaces nutrients from cation exchange sites > leached away > no longer available for plant growth.
the toxic aluminium is soluble in water at low pH, and it injuries plants and soil microorganisms.
what is the chemical equiation for ammonium fertilisation?
NH4^+ > NO3^- + H+
what are the 4 types of soil degradation?
wind erosion
chemical degradation
physical degradation
water erosion
what are the 5 underlying causes of soil degradation?
agricultural activity overgrazing industrial activity deforestation overuse of vegetation
what is a yield plateaus?
?
what does REDD+ stand for?
reducing emissions from deforestation and forest degradation
what is REDD+?
it is a biomass sink enhancement, trying to stop deforestation 1.1 GtC/y
it removes CO2 by restoring forest capacity over the next 50 years at the average rate that allows current second growth forests to reach maturity 2GtC.y, restore degraded forests 1 GtC/y and reforest recently deforested land 1
what does the + in REDD+ signify?
+ conservation of forests
+ sustainable management of forests
+ enhancement of forest carbon stocks
what is the 4 per mille initiative?
it is a growing international coalition of nation-states, international organisations, NGO’s, research centers, universities, farmers organisations and businesses,
the amount of C stock increase needed to offset CO2 emission
what are 5 practices that increase soil organic carbon?
conservation tillage, residue management and mulch farmin g
apply organic wastes to soils
use N and other nutrients sources more efficiently
eliminate summer (bare) fallow and incorporate legumes and other appropriate crops in rotations
agroforestry
what are examples of effectiveness of agricultural schemes in regards to carbon benefit and the 4 per mille initiative?
new hedgerow
cover crops
min till
what are regenerating soils
restoring soils to sequester carbon back where it belongs, in the soils and int he plants. it is the most efficient and safest climate mitigation strategy
what is the safest climate mitigation strategy in terms of soils?
regenerating soils
when using regeneratng soils, what increase of tonnes in grain-producing would you see?
24-40 million metric tonnes in grain production at a global level
is regenerating soils feasible?
it depends on how much carbon is there already. if the initial C stock is higher, there is a LOWER sequestration rate, this can be shown in a graph.
it also depends on how long improved management has been practised on the site. the higher the number of years, the lower sequestration rate is
what other aspects need to be considered when determining regenerating soils?
CH4 and N2O
incorporating rice straw is common practice
it improves plant growth and waterlogged conditions slow decomposotion
but it leads to a very high CH4 emissions from rice fields
what is biochar a product of?
pyrolysis of biomass
heating of biomass in low oxygen environments
how is biochar collected?
carbon captured by photosynthesis (biomass) from the atmosphere is locked into the biochar, preventing degradation and return of carbon into the air. Biochar is then applied into the soil.
what is pyrolysis?
thermal decomposition int eh absence of oxygen.
what is gasification?
the conversion of biomass into CO, CO2, H, CH4, and N with a limited supply of oxygen and steam
what are the products of pyrolysis?
gas, bio-oil and solid char
what are the products of gasification?
syngas and char
what can biochar be used for?
negative emission technology and improved soil fertility. it is very stable in the soil and degraded over centuries
what is bioremediation?
polyaromatic hydrocarbons, which can improve soils by direct intervention.
what is lignin
a plant polymer in the soil
why is lignin needed for biostimulation?
lignin is added to the soil to stimulate the growth of microbes. lignolytic enzymes can also transform some PAHs
these are produced mostly by fungi and some bacteria
what is phytoextraction
this is when phytoremediation enhances PAH dissipation from soil by plant uptake
what is rhizoremediation?
during phytoremediation, this can be stimulated microbe activity through root exudates.
what is Rhamnolipid, and why is it important during biostimulation?
it is a biosurfactant produced by pseudomonas aeruginosa.
it is a surfactants used to increased water solubility of hydrophobic organic pollutants
enhances plant uptake and microbial degradation
biosurfactants are less toxic than artificial surfactants and are biodegradable.
in the experiment looking at PAH in the Chinese Farm soil, what did the results show?
it shows that there is no PAH reduction when any reduction when any treatment used alone.
it showed that Ramnolipid is essential, and maximum dissipation is around 50% in the combined treatment
what is the ruminant digested system?
the digestive system changes food nutrients into compounds that are easily absorbed into the bloodstream.
what is a ruminant?
animals that contaain a multi-chambered digestive system.
how do ruminant animals get their nutritional needs?
from forages and other roughages
what are the major sources and sinks of GHG’s?
sources: anthropogenic, cows, faeces.
sinks: grass
what percentage of GHG emissions does livestock contribute to?
14.5%
which GHG emissions are from livestock?
applied and deposited manue, N2O fertiliser and crop residues, N2O Feed: Rice, CO2 Feed, CO2 LUC, Soybean, CO2 LUC: Pasture expansion, CO2 Enteric, CH4 Manure Management, CH4 Manure management CO2 Indirect energy, CO2 Direct energy CO2 Postfarm CO2
which pollutants are classed as GHG emissions from agriculture, but arent actually GHG?
NH3 and NOx
what is life cycle assessment
a tool to assess potential environmental impacts throughout a product’s life cycle
what 4 categories does grain crop production go to?
grain fed to people - 47%
grain fed to animals - 36%
other - 12%
biofuels, 5%
how many tonnes of crop in 2007 was produced?
2000 million tonnes
how many people could US feed with the grain that livestock eat?
800 million
what are feedlots in the USA?
calves spend one year in a pasture, and then they are transferred to a feedlot for “finishing” and fed high energy grains. they are slaughtered at 14-19 months.
what are the disadvantages of feedlots?
environmental, antibiotics in feed, grain production and shipment, animal welfare
what is grass-fed in the USA?
when animals entire lives are in pasture. they are slaughtered when ages 18-24 months.
what is the disadvantages of grass-fed lifestock?
more land is required.
GHG emissions are 37% higher due to longer finishing times and weight
what are some potential options to reduce CH4 and N2O
transferring the low microbiome of low methane producing ruminants finding new traits for GHG emissions vaccines to reduce methane production in the rumen carbon sequestration increase disease resistance select low-methane producing ruminants improved performance, low-quality feed storage cover feed supplement precision feeding dietary improvement and substitutes efficient and robust animals improving forage quality prevention, control and eradication of diseases collection and storage facility temperature and aeration of manure pasture management grazing practices capturing biogas from anaerobic processes
can grazing enhance soil carbon?
yes, they promote the growth of extensive roots and manure adds to soil carbon.
it maintains UK grassland landscapes without grazing would required mechanical mowing
what is holistic management?
planning grazing, regenerative grazing, mob grazing. things to enhance soil carbon
can holistic grazing balance the beef industry footprint?
partly, but not entirely according to various reports.
