Cycling of individual molecules + atoms occurs on diff. timescales: days - millions of years

LT storage in sed. rocks holds 99.9% of all C on Earth

Systems - groups of objects and the relationships that bind the objects together

Only energy not matter crosses the boundaries of the global water and C cycles = hence they are closed

Drainage basin, forest ecosystems

Most natural cycles exist in this state if not affected by human activities

Dynamic - continuous inputs, thruputs + outputs + variable stores of energy + mats.

In LT, flows + stores remain in balance = allows system to retain stability

Water Cycle In a drainage basin, heavy rainfall will increase the amount of water stored in aquifers, which will raise the water table, increasing flow from springs until the water table reverts to normal levels -

C Cycle Burning fossil fuels increases atmospheric CO2, but also stimulates photosynthesis - this will remove excess CO2 from atmosphere and restore equilibrium

Artificial surfaces are largely impermeable = little/no infiltration = minimal water storage capacity to buffer runoff

Urban development on floodplains reduces water storage capacity in drainage basins = increased river flow and flood risks

Crop irrigation diverts surface water from rivers and groundwater to cultivated land

Some irrigation water is extracted by crops from soil storage and released by transpiration; but most is lost to evaporation and in soil drainage

Interception of rainfall is less than in forests and grassland ecosystems

Furrows ploughed downslope act as drainage channels, accelerating runoff and soil erosion

Infiltration due to ploughing is usually greater in farming systems

Artificial underdrainage increases the rate of water transfer to streams + rivers

Surface runoff increases where heavy machinery compacts soils

Peak flows on streams draining farmland are generally higher than in natural ecosystems

Water is extracted from surface and groundwater to meet public, industrial and agricultural demands

Direct human intervention int he water cycle changes the dynamics of river flow and groundwater storage

River Kennet, S England drains an area of 1,200 km2 in Wiltshire and Berkshire

Chalk stream - so river supports a diverse range of habitats and wildlife: native fauna, Atlantic salmon, brown trout, water voles

Rates of groundwater extraction have exceeded recharge rates, and the falling water table has reduced flows by 10-14%

Lower flows = reduced flooding and temp. areas of standing water and wetlands on the floodplain

Lower groundwater levels = dried up springs + seepages, and reduced incidence of saturated overland flow on the chalk

To release of C into atmosphere from combustion of fossil fuels is to capture and store CO2 released by power plants and industry

This new tech. has been piloted at only a few coal-fired power stations

2. CO2 is compressed and transported by pipeline to storage areas

3. CO2 is injected into porous rockd deep underground where it is stored permanently

CCS could reduce these emissions by 80-90%

Uses large amounts of energy - 20% of a power plant's output is needed to separate the CO2 and compress it

Requires storage reservoirs with specific geological conditions e.g. porous rocks overlain by impermeable strata

Higher temps. in summer = more evaportransp. + lower exhaustion of soil moisture + river flows

Seasons are ultimately controlled by variations in the intensity of solar radiation

Climatic shifts have had a huge impact on the water + C cycles

As ice sheets advance towards equator they destroy extensive forest and grassland

Area covered by vegetation and water stored in biosphere shrinks

In tropics. climate becomes drier and deserts and grassland displace large areas of rainforest

This coupled with there being so much freshwater stored as snow and ice, slows the water cycle considerably

In warmer, inter-glacial periods, CO2 concs. can be 100 ppm higher

Phytoplankton fix large amounts of CO2 by photosyn. before dying and sinking into deep ocean where C is stored

Lower ocean temps. make CO2 more soluble in surface waters

During this process, deserts expand, tundra replaces temperate forests and grasslands replace tropical rainforests

With much of the land surface covered by ice, C stored in soils will not longer be exchanged with the atmosphere

Expanses of tundra beyond the ice-limit sequester huge amounts of C in permafrost

Less vegetation, fewer forests, lower temps. and lower precip, NPP and total vol. of C fixed in photosynthesis will declinle

Overall implications are a slowing of the C influx and smaller amounts of CO2 returned to atmosphere thru decomposition

Increased levels of CO2 + other greenhouse gases in atmosphere drive global warming and focus attention on linkages between atmosphere, oceans, vegetation, soils and cyrosphere

CO2 plays a vital role in photosynthesis by terrestrial plants + phytoplankton

Plants are imp. C stores + also extract water from the soil and transpire it as part of the water cycle

Water is evaporated from the oceans to the atmosphere and CO2 is exchanged between the 2 stores

Acidity increases when CO2 exchanges are not in balance (e.g. inputs to oceans from atmosphere exceed outputs)

Solubility of CO2 in oceans increases with lower sea surface temps.

Water availability influences rates of phtotsyn, NPP, inputs of organic litter to soils and transpiration

Temperatures and rainfall affect decomposition rates and the release of CO2 to the atmosphere

Co2 levels in atmosphere determine intensity of greenhouse gas effect and melting of ice sheets, glaciers, sea ice and permafrost

Melting exposes land and sea surfaces which absorb more solar radiation and raise temps. further

Permafrost melting exposes organic material to oxidation and decomposition which releases CO2 + CH4

Rapid pop. + economic growth, deforestation and urbanisation in the past 100 years have modified the size of water + C stored and rates fo transfer between stored in water and carbon cycles

Some C stores are being depleted whilst others are being increased

World relies on fossil fuels for 87% of its primary energy consumption

Exploitation of coal, oil + gas has removed billions of tonnes of C from geological store - this process has gathered momentum in past 30 years with the rapid industrialisation of Chinese + Indian economies

8 billion tonnes of C/year are transferred to atmosphere by burning fossil fuels

Land use change (mostly deforestation) transfer 1 billion tonnes of CO2 to atmphere annually

Additional C is stored mostly as atmospheric CO2 where its concentration continually increases

Around 2.5 million tonnes is absorbed by oceans - and a similar amount by biosphere

So the amount of C stored in biosphere and fixed by photosyn. has declined steeply

Acidification of the oceans threatens this vital biological C store + marine life

Soil is eroded via deforestation and agricultural mismanagement

C stores in wetlands, drained for cultivation and urban developments, have been depleted as they dry out and are oxidised

More water vapour (natural GHG) raises global temps. further, increasing evaporation and precipitation - POS. FEEDBACK

Global warming accelerates the melting of glaciers, ice sheets and permafrost

Water storage in cryosphere shrinks, as water is transferred to the oceans and atmopshere

Higher global temps. will generally increase rates of decomposition and accelerate transfers of C from biosphere and soil to the atmosphere

As forests are replaced by grassland, the amount of C stored in tropical biomes will diminish

In high latitudes, global warming will allow the boreal forests of Siberia, Canada and Alaska to expand polewards

C frozen in permafrost of the tundra is being released as temps. rise above freezing and allow oxidation and decomposition of vast peat stores

Acidification of the ocean through the absorption of excess CO2 from atmosphere reduces photosynthesis by phytoplankton, limiting the capacity of the oceans to store C

LT climate change will see an increase in C stored in the atmosphere, a decrease in biosphere and possibly a similar decrease in ocean carbon stores

Movement of C into and out of atmosphere will vary regionally, depending on changes in rates of photosynthesis, decomposition and respiration

Wetlands include freshwater marshes, salt marshes, petlands, flooplains and mangroves

Water table at or near the surface= ground is permanently saturated

Population growth, economic development and urbanisation = pressure on wetland environments

Loss of BD + wildlife, + transfers of huge amounts of stored CO2 and methane to atamosphere

Climate change has ld to a re-evaluation of wetlands as imp. C sinks

1122 ha have been targeted for restoration - should sequester 364,000 tonnes C/year

Protection as wildlife habitats e.g. management initiatives such as the International Convention on Wetlands

Restoration focuses on raising water tables and re-recreate waterlogged conditions

Wetlands on floodplains can be reconnected to rivers by the removal of flood embankments and controlled floods

Coastal areas of recliamed marshland used for farming cna be restored by breaching sea defences

Water levels can be maintained at artificially high levels by diverting or blocking drainage ditches and installing sluice gates

Overcultivation, excessive intensification + overgrazing are unsustainable and cause soil erosion and release of large quantities of C into atmosphere

Intensive livestock famring produces 100 million tonnes/year of CH4

CH4 emissions form flooded (padi) rice fields and from uncontrolled decomposition of manure

Zero tillage - growing crops without ploughing the soil - conserves the soil's organic content, reduces oxidation and the risk of erosion

Polyculture - growing annual crops interspersed with trees - trees provide year-round ground cover + protects from erosion

Crop residues - leaving crop residues on fields after harvest to provide ground cover and protection from erosion and drying out

Avoiding use of heavy farm machienry on wet soils which leads to compaction and risk of erosion by runoff

New strains of rice that grow in drier conditions and therefore produce less CH4 + chemicals (e.g. ammonium sulphate) which stops microbial activities that produce CH4

Improving quality of animal feed to reduce enteric fermentation so that less feed is converted to CH4; mixing methane inhibitors with livestock feed

Controlling the way manure decomposes to reduce CH4 emissions

Storing manure in anaerobic containers and capturing CH4 as a source of renewable energy

Multilateral organisations e.g. UN and WB recognise the importance of forests in he water cycle

These multilaterals co-operate with organisations and governments to fund programmes to protect tropical rainforests

The UN's Reducing Emissions from Deforestation and Forest Degradation (REDD) scheme and the WB's Forest Carbon Partnership Facility fund over 50 partner countries in Africa, Asia-Pacific and South America

Financial incentives to protect forests include C offsets and direct funding

Protects the genetic bank provided by thousands of plant species in the forest

Agriculture is the largest consumer - accounts for 70% of global water withdrawals and 90% of consumption

Recovery and recycling of waste water is feasible, but used little outside the developed world

Water agreements divide up resources between downstream states

The Punjab and Sindh in Pakistan receive 92% of the Indus' flow

Water resources from the Colorado Basin are allocated to California, Arizona, Nevada, Utah and New Mexico

Management of water resource sis most effective at the drainage basin scale

Integrated and holistic management approaches to accommodate conflicting demands of different water users

Conserving and restoring wetlands, inc. temporary storage in floodplains

Levels are maintained by limiting abstraction (e.g. for public supply, farming and recharge)

Artificial recharge - water is injected into aquifers through boreholes

The plan sets targets in relation to water quality, abstraction rates, groundwater levels, flood control, floodplain development and the status of habitats and wildlife