elss Flashcards
Explain Goldilocks zone
Earth is perfect distance away from sun to have right temperature for liquid water
How does water regulate Earths temperature
Water has a high specific heat capacity
Helps to create the benign thermal conditions on Earth
Water absorbs heat, stores it and releases it
Water usage in the economy
Generation of electricity Irrigation Recreation Public Demand Industry
Stores of carbon
Carbonate rocks Sea floor sediments Ocean water Atmosphere Biosphere
What is a system
Groups or objects and the relationship that bind the objects together
What is a closed system
A system with inputs and outputs of energy, but without any movement of material across the system boundaries
What is a open system
A type of system whose boundaries are open to both inputs and outputs of energy and matter
Carbon and water cycle are what kind of systems
Closed
What is the global water cycle
A closed system between the atmosphere, the oceans, land and the biosphere, timescales of transfer rates vary from days to millions of years
What are the major stores
Atmosphere - smallest store
Land
Ocean - largest store
What are the major processes of the water cycle
Precipitation
Evapotranspiration
run-off
Groundwater flow
Inputs of water to the atmosphere
Water vapour evaporated from the oceans, soils, lakes and rivers
Vapour transpired through the leaves of plants
Water leaving the atmoshpere
Precipitation - rain, snow, hail
Condensation - fog
Ice sheets, glaciers and snowfields release water by ablation
Water on the land
Precipitation and melt-water drain from the land surfaces as run-off into rivers
Most rivers flow into oceans
Precipitation reaches rivers after infiltrating the soil
Water in the soil may percolate into permeable rocks
The global carbon cycle
Long term storage in sedimentary rocks holds 99.9% of all carbon on earth
The main pathways between stores followed by carbon in this cycle include photosynthesis, respiration, oxidation and weathering
mportant roles
Carbonate rocks hold the most carbon
The carbon stored in the atmosphere, plants and soil is relatively small but these stores are crucial to the cycling of carbon
The slow carbon cycle
Carbon stored in rocks, sea floor sediments and fossil fuels is locked away for millions of years
10-100 million tonnes a year
The fast carbon cycle
Carbon circulates most rapidly between the atmosphere, the oceans, living organisms and soils
10-1000 times faster than those in the slow carbon cycle
The water balance
Summaries the flows of water in a drainage basin over time
Precipitation (P) = Evapotranspiration (E)+ Streamflow (Q)+/- Storage
Flows
Precipitation, Evaporation, Transpiration, run-off, infiltration, percolation, throughflow
Precipitation
Water and ice that falls from the clouds towards the ground
Precipitation forms when vapour in the atmosphere cools to its dew point and condenses into tiny water droplets or ice particles to from clouds
What is dew point
the atmospheric temperature (varying according to pressure and humidity) below which water droplets begin to condense and dew can form.
Transpiration
Diffusion of water vapour to the atmosphere from stomata
10% of moisture in the atmosphere
Influenced by temperature and wind speed
Influenced by water availability to plants
Condensation
Change of vapour to liquid
Occurs as water cools to its dew point
At this point air becomes saturated with vapour resulting in condensation
Clouds form through condensation in the attmosphere
Cumuliform clouds
Flat bases
Considerable vertical development
Form when the air is heated locally through contact with the Earths surface
The heated air parcels rise freely in the atmosphere, expand and cool
Stratiform clouds
Layer clouds
Develop where an air mass moves horizontally across a cooler surface - advection
Cirrus clouds
Wispy clouds
Form at high altitudes
Consist of tiny ice crystals
Do not produce precipitation
Cloud formation and lapse rates
Cooling occurs when
Air warmed by contact with the ground or sea surfaces, rises freely through the atmosphere and pressure falls it cools by expansion
Air masses move horizontally across a relatively cooler surface
Air masses move horizontally across a relatively cooler surface
Air masses rise as they cross a mountain barrier or as turbulence forces their ascent
What are Lapses rates
The vertical distribution of temperature in the lower atmosphere, and temperature changes that occur within an air parcel as it rises vertically away from the ground
What is evaporation
The phase change of liquid to water vapour
Main pathway by which water enters the atmosphere
Latent heat
The energy input of evaporation does not lead to an increase in temperature
Instead the energy is absorbed as latent heat and released later in condensation
Interception
Vegetation intercepts a proportion of precipitation, storing it temporarily on branches, leaves and stems
This water will either evaporate or fall to the ground
Throughfall - rainwater which is briefly intercepted before dripping on to the ground
Stemflow - during prolonged or intense periods or rainfall, intercepted rainwater may flow to the ground along branches and stems
What is infiltration
By gravity into the soil and lateral movement or throughflow to stream and river channels
What is overland flow
Across the ground surface either as a sheet or as trickles and rivulets to stream and river channels
What are the main processes involved in carbon exchange
Precipitation Photosynthesis Weathering Respiration Decomposition Combustion
How is precipitation involved in the carbon cycle
Atmospheric C02 dissolves in rainwater to form weak carbonic acid
Human activities are increasing the acidity of rainfall resulting in ocean surface waters becoming more acidic
How is photosynthesis involved in the carbon cycle
The flux of carbon from atmosphere to land plants and phytoplankton via photosynthesis averages around 120 gigatonnes
CO2 is used in photosynthesis
What is weathering
In situ breakdown of rocks at or near the surface
Chemical, biological and physical processes
Explain chemical weathering
Most weathering involves rainwater which contains dissolved CO2
This dissolves carbonate rocks
Transfers carbon to the atmosphere, streams, rivers and the ocean
Explain physical weathering
Freeze-thaw breaks rocks donw into smaller particles but involves no chemical weathering
This process increases the surface area exposed to chemical processes
What is downwelling
When water cools and becomes more dense then sinks
Effect of downwelling on carbon cycle
Carries dissolved carbon to the ocean depths where individual carbon molecules may remain for centuries
What is upwelling
Eventually deep ocean currents transport the carbon to areas of upwelling
Carbon-rich water rises to the surface and CO2 diffuses back into the atm
How does urbanisation disrupt the dynamic equilibrium
Natural surfaces replaced by impermeable surfaces
Drainage systems remove water rapidly
How does development on flood plains disrupt dynamic equilibrium
Floodplain are natural storage areas for water
Urban development on these areas reduce water storage capacity
How does farming disrupt dynamic equilibrium
Crop irrigation diverts surface water from rivers and groundwater to cultivated land
Interception, evapotranspiration is reduced
Ploughing increases soil moisture loss
Furrows act as drainage channels
How does arable farming effect the carbon cycle
Soil carbon storage is reduced by ploughing
Harvesting crops takes away carbon
Soil erosion increased by harvesting
What is carbon capture storage
The process of capturing carbon from the atmosphere and then storing it where it will not reach the atmosphere for some time (normally underground)
What are the limitations of carbon capture storage
Involves big capital costs
Uses a large amount of energy
Require specific geological conditions for storage
Why are observation by satellites so important
Ground based observations of environmental changes at a global scale would be impractical
GIS techniques map and analyse the data to show areas of anomalies and trends and areas of greater risk
Why does data need to be collected
Identifying change is key to predicting and managing issues
Lets us know what is normal
Explain Diurnal change with examples
Significant changes over a 24 hour period
Low evaporation and transpiration at night
Conventional precipitation is dependant on direct heating of the ground surface, often falls during the afternoon
What are seasonal changes controlled by
Variations in the intensity of solar radiation
Transpiration is highest in summer
What are long term changes
Glacial cycles
Four major ones
Glacial and interglacial
What happens during glacial periods
Net transfer of water from the ocean to storage in ice, glaciers and permafrost
Ice sheets destroy grassland
Water stored in biosphere shrinks
Low rates of transpiration
Diurnal changes in the carbon cycle
Daytime CO2 flows from the atmosphere to vegetation, this is then reversed at night
Seasonal changes in the carbon cycle
Monthly changes in the NPP
Northern hemisphere in summer, trees are in full foliage, net movement of CO2 to the biosphere
Phytoplankton are stimulated into photosynthetic activity by rising water temperatures and more intense sunlight
Long term changes in CO2
CO2 levels drop in glacial periods
During interglacial activities CO2 is higher
The carbon pool in vegetation sinks during glacial periods
Tundra replaces forests
Tundra sequesters carbon in permafrost
How does the atmosphere links the cycles
CO2 plays a vital role in photosynthesis
Plants extract water from soil and transpire it to the atm
water is evaporated from the oceans
CO2 is exchanged from the ocean to the atm
How does the oceans link the cycles
Ocean acidity increases when exchanges of CO2 are not in balance
Solubility of CO2 in the oceans increases at lower sea-surface temperatures
CO2 influences SST and thermal expansion, melting of ice and air temperatures
How does vegetation and soil link the cycles
cycles
Water availability influences the rate of photosynthesis, NPP
Water storage capacity of soils increases with organic content
Temperature and rainfall affects decomposition rates and the release of CO2 to the atm
Temp and rainfall affects decomposition rates and release of CO2 to atm
How does the Cryosphere link the cycles
CO2 levels in the atm determine temp and melting of ice sheets, glaciers and permafrost
Melting expose land and sea surfaces which absorb more radiation and increase temp
Run-off, river flow and evaporation respond to temperature change
Name some management stratagies
Wetland restoration
Afforestation
Sustainable agriculture practices
Control greenhouse emissions
What are the threats to wetlands
Population growth
Economic development
Urbanisation
What are the threats to forests
Logging
Farming
Mining
Management - Land and crop management
Zero tillage Polyculture Crop residues Avoiding using heavy machinery Contour ploughing and terracing
Management - manure management
Control way manure decomposes to reduce amount of methane produced
Capturing methane to use as a renewable source
Paris agreement
Reduce global CO2 emissions below 60% of 2010 levels by 2050
Cap and trade
Alternative, international market- based approach to limit CO2 emissions
Can purchase credits for those who need a bigger quota of other companies
Afforestation in China
Aim to afforest 400, 000km2 by 2050
Non-native, fast growing species such as popular and birch
Combats desertification and land degradation in the semi-arid expanses of northern china
Forestry threats
Increasing demand for resources and space threaten the forests
Funding projects
UN - REDD
World bank
Financial incentives to protect and restore forests
Brazil’s protected areas
Recieved support from UN, World Bank, WWF and the German Development Bank
Benefit of protecting Brazils areas
Stabilizing the regions water cycle
Offsetting 430 million tonnes of carbon a year
Supporting indigenous forest communities
Promoting ecotourism
Agriculture - improved management techniques to prevent water losses
Mulching
Zero soil disturbance
Drip irrigation
Agriculture - Reducing run-off on slopes
Terracing
Contour ploughing
Insertion of vegetative strips
Water withdrawal conflicts
Pakistan accounts for approx 63%
Afghan for 1%
India for 36%
China for 0.04%
Water allocation 1961
In 1961, India and Pakistan signed a treaty
Drainage basin planning
Most effective to manage water at the basin scale
Need to manage to accommodate the conflicting demands
Social - domestic, recreation
Economic - agriculture and industry
Environmental - wildlife
