Earth’s Life Support Systems

Management strategies for global water cycle

Forestry: UN + World Bank fund programmes to protect rainforests REDD scheme fund 50+ partner countries World Wildlife Fund (WWF) + Amazon Regional Protected Areas (ARPA) supported by UN in brazil to protect forests. Covers 10% Amazon basin (areas strictly protected)...

read more

Variations to cycles over time

Monitored by Geographical Information Systems (GIS) and used to analyse environmental change. Regional variations in sources and sinks helps identify sequestration and emission management options. Vital to manage global challenges of climate change, water, food and...

read more

Short-term changes

Diurnal (daily) Changes – Water = Low temps reduce evapotranspiration at night. Convection rainfall significant in Tropical convectional storms occurs during the day. Carbon = Daytime photosynthesis by terrestrial vegetation and phytoplankton. Flux reversed at night....

read more

Long-term Changes

For 1 million years the global climate has been unstable, with large fluctuations in temperatures at regular intervals. In the past 400,000 yrs there has been 4 major glacial cycles (cold glacials followed by warmer interglacials). Glacials and the water cycle = Sea...

read more

Links and interdependence in the two cycles

Atmosphere: • Atmospheric CO2 has a greenhouse effect. • CO2 plays a vital role in photosynthesis by terrestrial plants and phytoplankton. • Plants are important C stores which extract water from the soil and transpire. • Water is evaporated from oceans to atmosphere,...

read more

Impact of long-term climate change of the cycles

Water: • Increased evaporation and atmospheric water store. Positive feedback of water vapour increases global temps, evaporation and transpiration. • Increased precipitation in urban areas leads to flood risks. • Water vapour is an atmospheric source of energy,...

read more

Management strategies for global carbon cycle

Afforestation: • C sink, reduce atmospheric CO2, flood risks and soil erosion. • UN’s Reducing Emission from Deforestation and Forest Degradation (REDD) schemes encourage LIDCs to conserve their forests, now has over 60 official partner countries. Wetland Restoration:...

read more

Feedback in response to change in equilibrium

Water: • Rising temp Positive feedback – More evaporation, atmosphere holds more water in clouds, increased absorption of long wave-radiation. • Decreasing temp Negative feedback – More atmospheric vapour in clouds cover, reflected solar radiation, less radiation...

read more

Case Study – The Arctic Tundra

Location, Vegetation and Climate: Occupies 8 million km2 in N.Canada, Alaska and Siberia. Continuous vegetation in Boreal Forest (southern) to discontinuous (northern). Low biodiversity and NPP. Average monthly temps sub 0 prevent evapotranspiration (ground...

read more

Land use change and water extraction

Urbanisation – Water • Impermeable surfaces reduce infiltration. • Urban drainage systems remove surface water rapidly. • River water levels rise rapidly due to fast transfer of surface water. • Developments on floodplains reduce storage capacity and increase flood...

read more

Fossil fuel combustion

• High global dependency 80% global energy consumption • 10 billion tonnes CO2 released annually. • Transfer from geological stores to atmosphere and oceans. • CO2 atmospheric levels highest in 800,000 years, risen above 400ppm. Although anthropogenic carbon emissions...

read more

Case Study – The Amazon Rainforest

Location, Vegetation and Climate: Straddles equator between the tropics. South America - 70% Brazil Brazilian Shield = large metamorphic field that limits infiltration and encourages surface flow. Tall, evergreen, hardwood trees. High NPP, biomass 500 tonnes/ha...

read more

The carbon cycle is a system with inputs, outputs and stores

• Lithosphere – Sedimentary rocks (99.9%) and fossil fuels. • Hydrosphere – Oceans Surface layer phytoplankton photosynthesis and diffusion Intermediate and deep layer marine food chains and sea floor sediments Calcium carbonate shells • Terrestrial/biosphere organic...

read more

The characteristics of the water cycle

The water balance: Precipitation = evapotranspiration + streamflow +/- storage • Precipitation forms when vapour in the atmosphere cools to its dew point and condenses to form droplets which aggregate and leave clouds. • Cumuliform clouds (high with flat bases) form...

read more

The water cycle is a system with inputs, outputs and stores

Global water cycle: • Oceanic - holds 97% of global water with ¾ in ice caps. • Cryospheric water- high altitudes and latitudes Accumulation is input to a glacial system Ablation is output from melting. Sublimation is ice directly into water vapour. • Terrestrial –...

read more