ELSS - Dynamic Equilibrium

dynamic equilibrium

continuous inputs, processes and outputs which can affect the balance year to year.

feedback loops

ether positive or negative, ether restoring the dynamic equalibruim or pushing git further out of balance

positive feedback

when a one change causes further changes in the system which can make the system unstable

positive feedback loop - water cycle

global increase- more evaporation- water vapour- GHG - more long wave radiation absorbed - atmosphere warms

positive feedback loop - carbo cycle

sea ice + snow cover shrinks - large expanses exposed - more sunlight absorbed - warming tundra - melting permafrost

negative feedback

when one change causes the system to alter so that equilibrium is recovered and the system does not change

negative feedback loop - water

increase cloud cover - more water vapour to condense- increase cloud cover reflects Moree incoming short wave radiation back out to space - less incoming radiation - decrease in temp

negative feedback loop - carbon

increased temp - more photosynthesis- fewer GHGin atmosphere - cooling

LUC - urbanisation - water

artificial surfaces - impermeable - more run off - flood risks - streams have short lag times + high but short peak flows

LUC - urbanisation - carbon

more fossil feul use - realises CO2 into atmosphere

LUC - farming - water

interception less than forest or grassland - less evaporation and transpiration from leafs - plotting increases evaporation and increase soil moisture loss

LUC - farming - carbon

clearance of forest - reduces carbon storage - plouging exposes the soil too oxidisation - reduces carbon storage

LUC - forestry - water

higher rates of interception on plantations than in natural forests - eg sitka spruce = 60% - increased evaporation

LUC - forestry - carbon

forest tress extract carbon form the atmosphere and sequester it for years - only do this first 100 years then felled

interdependance

the 2 cycles are interlinked and interdependent, if one factor changes it will affect the other

interdependance - atmosphere

Co2 contributes to greenhouse effect - plants have vital role in sequestering it - plants extract water from soil and transfer it

interdependance - oceans

lower STTs = higher CO2 solubility - atmospheric co2 influences STTs, air temps - influences melting of ice and hence sea levels

Interdependence- vegetation and soil

water availability affected photosynthesis rates affect NPP

Interdependence - cryosphere

CO2 levels in atmosphere effect global temps, affect ice sheets melting - melting exposes land which rises temp further - increases evaporation

water cycle management - water allocations

goverrments can allocate water though aggrements by changing the market price of water and restitcing abstraction. however depriving some areas of the river and changes of distribution can cuase problems, agriculture is the biggest consumer of water accounting for 75% of global water withdraws - to much water being lost to evaporation - crop breeding and drip irrigation

water allocations - example

Colorado river - do not deplete flow of the river below 93km3 during any consecutive period of 10 years, provides 40 million people in 7 states, cut backs are required or the river will run out

water cycle management - forests

trees intercept precipitation and soak up water through their roots reducing surface storage run-off

forestry - amazon rainforest

almost 60% of the Amazon basin is protected from activities such as logging. ARPA amazon regional protected area

water cycle management - drainage basin planning

the imputs, stores and outputs can often be managed effectively, rapid run-off is controlled by reforestation programmes in planned catchments, important as it ensures the needs for a community, the economy and the enviorment are met and sustained, also allows water to be used in a more sustainable way

drainage basin planning - example

the nile basin inititive, looks to develop teh river in a coopretive manner, to share socio-economic benifits and promote regional peace and security, aggrement includes countires eg egypt, sudan, ehtiopia and uganda, opend in 2010

monitoring changes - artic sea ice

measure microwave energy radiated from earths surface, comparison of time series images to show changes

monitoring changes - SSTs

radiometers measure the wave band of radiation emitted from the ocean surface. changes in global SSTs and areas of up welling + downwelling

monitoring changes - Deforestation

measurements of reflectivity or earths surface and land use changes

why data is monitored and collected

due to their potentially damaging impact of climate change 

carbon management - afforestation

planting secondary forests will increase carbon store in biomass china UN REDD Scheme - successfully planted 30,000km2 by 2009

carbon management - wetland restoration

includes freshwater and saltmarches, peatlands, floodplains and mangroves contain 35% of terrestrial pool. UK - running small schemes - government target of 500 ha of wetlands restored by 2020

carbon management - improving agricultural techniques

poly culture - growing annual crops interspersed with trees, providing year round ground cover + protect soils

carbon management- international agrements - paris

the Paris climate convention of 2015, the Paris agreement was reached, started aims to reduce global CO2 emmisons below 60% of 2010 levels by 2050

carbon capture and storage

aims to reduce CO2 emissions from fossil fuel combustion in particular in Gas and coal power stations 

carbon capture and storage stages

This separating co2 from waste gas emissions

transporting the captured co2

secure LT storage of CO2 underground

15 large CSS projects around the world eg Canada

inporved forestry

regulated and planned cutting of trees to reduce deforestation levels, reduce forest fires as forest are important to keep water cycle in dynamic equilibrum

imporved foresty exmaple

amazon - since 1998 many forest conservation areas have been created covereing 20x the sixe of belgium, parica project in western amazon aims to develop 1000km2 of commercial timber planations however this wont replace biodiversity as is monoculutre