how much change occurs over time in the water and carbon cycle? Flashcards
global energy consumption %
Oil 37%
Natural gas 27%
Coal 23%
how much CO2 is released annually?
10 billion tonnes
anthropogenic carbon emissions affect what stores?
the size of the atmosphere, ocean + biosphere
what is the driver of present day global warming?
the combustion of fossil fuels + the transfer of carbon from geological stores to the atmosphere + oceans
what is the solution to these emissions?
to capture and store Co2
new tech of carbon sequestration is know as carbon capture + storage
what happens during carbon capture + storage?
the Co2 is separated from power station emissions, then it is compressed + transported by pipeline to storage areas, then it is injected into porous rocks deep underground where it is stored permanently
how much has atmospheric Co2 concentrated increased from 1750-2012?
280 -> 393
in USA what % all Co2 are coal + gas fired stations?
40%
what % is CCS likely to reduce emissions by?
80-90%
why is the technology of CCS limited in effectiveness?
- involved big capital costs eg the Drax + Peterhead projects will cost at least £1 bill
- uses large amounts of energy - typically 20% of a power plant’s output is needed to separate the Co2 + compress it
- requires storage reservoirs with specific geological conditions
what are diurnal changes?
changes that occur within 24 hour period
what changes occur at night?
lower temp -> reduce evaporation + transpiration
when does convectional precipitation take place?
daytime (when temps reach max), dependent on direct heating of the round surface by the sun
how does carbon flow in the daytime?
CO2 flows from the atmosphere to vegetation
how does carbon flow at night-time?
without sunlight, photosynthesis switches off + vegetation loses co2 to atmosphere
also observed with phytoplankton in the oceans
how are seasons controlled?
variation in the intensity of solar radiation
when does solar radiation peak in the UK?
mid June eg around 800 W/m2 where as in Dec 150 W/m2
when is evapotranspiration highest + lowest?
highest = summer, lowest = winter
why are river flows normally at their lowest in late summer?
large losses of precipitation to evapotranspiration + the exhaustion of soil moisture
how are seasonal variations shown in the CC for month to month changes?
net primary productivity of vegetation
when is there a net global flow of Co2 from atmosphere to biosphere?
Northern hemisphere summer - trees in full follages
- > causes atmosphere Co2 levels to fall by 2 ppm
- > at the end of summer as photosynthesis ends, the flow is reversed with natural decomposition releasing co2 back to the atmosphere
what has a global impact with seasonal changes?
the concentration of continental land masses -> during growing season ecosystems eg the boreal + temperate forests extract huge amounts of Co2 from atmosphere
what is the climate record like over last 1 mill years?
highly unstable
there has been four major glacial cycles - cold glacials followed by warmer interglacials, each cycle lasting around 100,000 yrs
200,000 yrs ago avg annual temps in British isles were 5C lower than today
during warm interglacials periods there were similar temps to today but on much longer timescales global temps have been even more extreme eg 250 mill years ago avg global temp reached 22C at least 7-8C higher than today
what changes does the water cycle undergo in glacial periods?
- in glacials the sea level worldwide falls by 100-130 m -> ice sheets + glaciers expand to cover 1/3 of the continental landmass -> as ice sheets advance they destroy extensive tracts of forest + grass land = the area covered by vegetation + water stored in biosphere shrinks
- in the tropics, climates becomes drier + deserts + grasslands displace large areas of rainforest
- lower rates of evapotranspiration reduces exchanges of water between the atmosphere + the ocean, biosphere + soils
- freshwater stored as snow + ice
SLOWS WC
