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)...
Earth’s Life Support Systems
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...
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....
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...
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,...
How human activities cause change in the availability of water and carbon
• Deforestation Reduces C store in biosphere and carbon fixation by photosynthesis. Increased soil erosion declines soil C store. Forest trees transfer water by transpiration and reduced interception increases run-off (20-30%) leading to flooding. E.g – The Amazon...
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,...
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:...
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...
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...
Human factors can influence the processes and stores in the water and carbon cycles
Human factors and the water cycle – The Aral Sea • Central Asia, used to be the fourth largest lake globally, now just 10% remains • Sea receded, rain stopped due to draining of the Syr Darya and Amu Darya rivers for Soviet cotton industry irrigation. • Division into...
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...
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...
The characteristics of the carbon cycle
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...
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...
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...
Water and carbon support life on Earth and move between the land, oceans and atmosphere
Importance of water: • Creates benign thermal conditions. Oceans are 71% of the world’s surface and they absorb, store and slowly release heat. Clouds reflect 1/5 of insolation. Water vapour (potent greenhouse gas) absorbs long-wave radiation and maintains global...
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 –...