Land use changes and its link to climate change Flashcards
Economic costs of GHG abatement
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How working out the abatement costs reduces overall emissions
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Agricultural land on Earth’s surface
Agricultural lands occupy 37% of the earth’s land surface. Agriculture accounts for 52 and 84% of global anthropogenic methane and nitrous oxide emissions.
Uk climate change committee recommendations of reducing emissions cost effectively from agriculture - 9 MtCO2e from measures that decrease N20 emissions from crops and soils including
reducing fertilizer application where it is applied in excess
matching the timing of application with the time when the crop will make most use of it
using organic rather than synthetic fertilizer when possible
improving drainage of land
selectively breeding plants that need less fertiliser.
Emissions intensity for different food products
Around 17kgCO2e/kg product for Sheep Meet
16kgCO2e/kg product for Beef
11kgCO2e/kg product for Milk
Williams et al (2006)
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Global land use change
Expansion of agriculture at expense of forests and natural grasslands
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Land use change and carbon cycle impact
US land use change in past 50 years has led to accumulation of carbon
Mainly due to reafforestation on previous agricultural land
Forestry impact on carbon to the atmosphere
Forestry, despite locking up carbon above ground, is a net source of carbon to the atmosphere because of loss of carbon from draining peatland and from afforestation of previous mature woodland
Socieities land use regimes over time
from presettlement natural vegetation to frontier clearing, then to subsistence agriculture and small-scale farms, and finally to intensive agriculture, urban areas, and protected recreational lands
Market solutions to carbon land use dilemmas
If the atmosphere is a global pubic good, then it is overused because it is undervalued. Market solution is to create rights and hence markets in carbon
UNFCCC created carbon markets through e.g. Clean Development Mechanism and REDD (Reduced Emissions from Deforestation and Degradation)
Land use change contribution to global Co2 emissions
Land use change, largely from deforestation , contributes up to 20—25% of global Co2 emissions
Incentives needed
Incentives needed to improve land management and reduce deforestation/degradation
A ton of CO2 sequestered by forests has an economic value defined by the “market”
Carbon sequestration
Actively managing land or forest ecosystems in order to increase biomass levels above present conditions e.g. reforestation, sustainable forest management etc
REDD
Avoided Deforestation and/or reducing emissions from deforestation and degradation (REDD): Avoiding emissions from land use change by protecting and conserving forest ecosystems at high risk of deforestation and degradation.
Forest Carbon projects and local livelihoods
Resource diversification and forest conservation
Increased collective and household income
Investment in infrastructure
Improved organizational skills around forest management
Ecological impacts
Exclusion of informal tenants.
Accounting carbon offsets or emissions reduced from avoiding deforestation
Managing land or forest ecosystems to increase biomass
Requires understanding of carbon flux across different carbon pools and throughout time
Requires rigorous methods for offset accounting
Ruminant GHG production
GHG emission from ruminant meat production are significant. Reductions in ruminant numbers could make a substantial contribution to climate change mitigation goals and yield important social and environmental co-benfits
Ripple et al (2014)
Non Co2 GHG contribution
At present non-CO2 GHGs contribute about a third of total anthropogenic CO2 equivalent emissions and 35-45% of climate forcing.
Ripple et al, 2014
Methane contribution
Methane is the most abundant non-CO2 GHG because it had a much shorter atmospheric lifetime than CO2 it holds the potential for more rapid reductions in radiative forcing than would be possible by controlling emissions of Co2 alone.
Ripple et al, 2014
Livestock sector emissions
Worldwide, the livestock sector is responsible for approximately 14.5% of all anthropogenic GHG emissions.
Approximately 44% of livestock sector emissions are in the form of Ch4 from enteric fermentation, manure and rice feed, with the remaining portions almost equally shared between CO2 from land-use change and fossil fuel use, and nitrous oxide
Ripple et al, 2014
Ruminant agriculture negatives
Ruminant agriculture can have negative impacts on water quality, and availability, hydrology and riparian ecosystems.
Ripple et al, 2014
Ruminant production negatives
Ruminant production can erode biodiversity through a wide range of processes such as forest loss and degradation, land use intensification, exotic plant invasions, soil erosion etc.
Ripple et al, 2014
Rates of meat consumpion in developed countries
In developed countries, high levels of meat consumption rates are strongly correlated with rates of disease such as obsesity, diabetes, some common cancers and heart disease
Ripple et al, 2014
Global expansion of croplands
One estimate holds that the global expansion of croplands since 1850 has converted some 6 million km2 of forests/woodlands and 4.7 millionkm2 of savannas/grasslands
Lambin et al (2001)
High rates of deforestation are linked
High rates of deforestation within a country are most commonly linked to population growth and poverty, shifting cultivation in large tracts of forests. The misconception that follows is that most tropical deforestation occurs by the “push” of population growth and poverty to invade, slash and burn the forest along the roads
Lambin et al (2011)
Rapidly developing land scarcity may trigger
Rapidly developing land scarcity may trigger increase in cropping frequency unmatched by appropriate changed in inputs or management, resulting in a “stressed” system, abandoned “landesque” capital and land degradation
Ripple et al, 2014
Forest gross photosynthesis
Every year forest gross photosynthesis cycles approximately one twelfth of the atmospheric stock of CO2, accounting for 50% of terrestrial photosynthesis.
Malhi et al (2002)
Maximum carbon sequestered
In the course of the whole century, however, even the maximum amount of carbon that could be sequestered will be dwarfed the magnitude of fossil fuel emissions
Malhi et al (2002)
Worldwide changes are being driven by
Worldwide changes to forests, farmlands, waterways, and air are being driven by the need to provide food, fiber, water and shelter to more than 6 billion people
Foley et al (2005)
Anthropogenic Co2 from land use
Since 1850, roughly 35% of anthropogenic Co2 emissions resulted directly from land use
Foley et al (2005)
Anthropogenic nutrient input
Anthropogenic nutrient inputs to the biosphere from fertilizers and atmospheric pollutants now exceed natural sources and have widespread effects on water quality and coastal and freshwater ecosystems
Malhi et al (2002)
Land use decline in biodiversity
Land use has also caused declines in biodiversity through the loss, modification, and fragmentation of habitats, degredation of soil and water, and overxploitation of native species.
Foley et al (2005)
One of the primary causes of environmental change
One of the primary causes of global environmental change is tropical deforestation
Foley et al (2005)
Reasons for tropical deforestation - public and individual level
at the underlying level public and individual decisions largely respond to changing, national-to global-scale economic opportunities and/or policies, as mediated by local scale institutional factors, and that, at the proximate level, regionally distinct modes of agricultural expansion, wood extraction, and infrastructure extension prevail in causing deforestation
Geist and Lambin (2002)