3.b. The pathways and processes which control the cycling of water and carbon vary over time. Flashcards
Why is it important for changes to be monitored?
(Monitoring changes to the global water and carbon cycles)
To assess the potentially damaging impact of climate change, as this is essential.
State 3 ways in which accurate monitoring of changes can be done.
(Monitoring changes to the global water and carbon cycles)
Global air temperatures.
Sea surface temperatures (SST).
Sea ice thickness.
Rates of deforestation.
Why does monitoring rely heavily on satellite technology and remote sensing?
(Monitoring changes to the global water and carbon cycles)
As ground-based measurements of environmental change at a global scale are impractical.
How can monitoring allow for observations on various time scales?
(Monitoring changes to the global water and carbon cycles)
Continuous monitoring by satellite on a day-to-day, month-to-month or year-to-year basis.
How can GIS techniques be used in relation to satellite data?
(Monitoring changes to the global water and carbon cycles)
Data can be mapped and analysed to show areas of anomalies and trends, and regions of greatest change.
What is GIS?
(Monitoring changes to the global water and carbon cycles)
Geographical Information Systems.
What is the NOAA?
(Remote sensing: satellite technology to monitor changes to the water and carbon cycles)
National Oceanic and Atmospheric Administration.
How is artic sea ice monitored?
(Remote sensing: satellite technology to monitor changes to the water and carbon cycles)
By NASA’s Earth Observing System, they have done this since 1978.
Measures microwave energy radiated from Earth’s surface.
Comparison of time series images are used to show changes.
How is sea surface temperature monitored?
(Remote sensing: satellite technology to monitor changes to the water and carbon cycles)
By NOAA satellites.
Radiometers measure the wave band of radiation emitted from the ocean surface.
Changes in global SSTs and areas of upwelling and downwelling.
How is deforestation monitored?
(Remote sensing: satellite technology to monitor changes to the water and carbon cycles)
By ESA albedo (reflectivity) images various satellites.
Measurements of reflectivity of Earth’s surface and land use changes.
When is rainfall the most common? Why?
(Diurnal (daily) changes)
(Short-term changes in the water cycle)
The afternoon.
As temps rise through the middle of the day and evaporation rates are highest. Convectional rainfall occurs once moisture has risen in atmosphere, and been cooled through lapse rates - produced as precipitation.
How is the water cycle impacted during the night?
(Diurnal (daily) changes)
(Short-term changes in the water cycle)
Temperatures drop.
This reduces evaporation and respiration.
Seasonal changes are influenced by what?
(Seasonal changes)
(Short-term changes in the carbon cycle)
Solar radiation.
How is the carbon cycle impacted on a daily basis?
(Diurnal (daily) changes)
(Short-term changes in the carbon cycle)
Phytoplankton and terrestrial plants.
Photosynthesis occurs in the daytime, especially during midday.
At night this reverses.
Solar radiation inputs in December (Southern England) can reach how high?
(Seasonal changes)
(Short-term changes in the water cycle)
150W/m2.
Solar radiation inputs in June (Southern England) can reach how high?
(Seasonal changes)
(Short-term changes in the water cycle)
800W/m2.
When does solar radiation peak? How does this impact the water cycle?
(Seasonal changes)
(Short-term changes in the water cycle)
June.
This means 80% of precipitation is lost, normally through evapotranspiration.
This can result in low river flows.
In the carbon cycle, there are considerable seasonal variation where? What is this?
(Seasonal changes)
(Short-term changes in the carbon cycle)
In the Tropics.
This is the difference between rainy and dry seasons and associated water availability.
When is vegetation at full foliage? What does this result in?
(Daylength in the UK)
(Seasonal changes)
(Short-term changes in the carbon cycle)
In the summer
This leads to a drop in atmospheric CO2.
By the end of the Summer, what rises? What rises back up?
(Daylength in the UK)
(Seasonal changes)
(Short-term changes in the carbon cycle)
By the end of Summer, decomposition rates rise and the drop in atmospheric CO2 is reversed (increasing).
Global CO2 changes are dominated by what? Why?
(Daylength in the UK)
(Seasonal changes)
(Short-term changes in the carbon cycle)
The Northern hemisphere.
This is because they have a much greater land mass.
In growing season, what leads to a huge drop in atmospheric CO2 levels? Where else does this happen?
(Daylength in the UK)
(Seasonal changes)
(Short-term changes in the carbon cycle)
In growing season, ecosystems such as the boreal forests extract huge amounts of CO2 from the atmosphere, having a global impact.
This also happens in the oceans, with phytoplankton blooms occurring when water temperatures rise, and there is more intense sunlight.
Phytoplankton blooms occur when water temperatures rise, and there is more intense sunlight. What time of the year is this? Where?
(Daylength in the UK)
(Seasonal changes)
(Short-term changes in the carbon cycle)
This occurs between March to June/ July in the North Atlantic ocean.
The resulting algal blooms are so extensive, they are visible from space .
Is the Earth’s climate stable? Why?
(Long-term changes in the water and carbon cycles)
The Earth’s climate is unstable.
This is because temperatures constantly fluctuate at regular intervals.
In the last 400,000 years, there have been how many glacial and interglacial period cycles?
(Long-term changes in the water and carbon cycles)
4 cycles of glacial and interglacial periods.
How long does each glacial and interglacial period cycle last?
(Long-term changes in the water and carbon cycles)
Around 100,000 years.
(glacial-interglacial-glacial).
When was the height of the last glacial period?
(Glacial periods)
(Long-term changes in the water and carbon cycles)
20,000 years ago.
20,000 years ago during the height of the last glacial period, global average temperatures were how much lower?
(Glacial periods)
(Long-term changes in the water and carbon cycles)
5°C lower.
20,000 years ago during the height of the last glacial period what covered Scotland, Northern Ireland, Northern England, and Northern Wales? What would this have caused?
(Glacial periods)
(Long-term changes in the water and carbon cycles)
An ice sheet averaging 1km thick.
This would have created isostatic change (Scotland rising back up, Southern England rising back down).
What are the temperatures of most interglacials like? What about 250 million years ago?
(Inter-glacial periods)
(Long-term changes in the water and carbon cycles)
A similar average temperature as today.
However, 250 million years ago global temperatures were even more extreme, with average temperatures being 22°C, (7-8°C warmer than today).
These climatic shifts had a major impact on the water and carbon cycles.
What happens to water during glacial periods?
(Water cycle)
(Long-term changes in the water and carbon cycles)
there is a net transfer of water from the ocean reservoir to storage in ice sheets, glaciers, and permafrost:
During recent glacial periods what have sea levels been seen to fall to?
(Water cycle)
(Long-term changes in the water and carbon cycles)
Global sea level fell by 100-130 m.
During recent glacial periods, ice sheets and glaciers have been seen to expand to cover what?
(Water cycle)
(Long-term changes in the water and carbon cycles)
Ice sheets and glaciers expand to cover 1/3 of continental land mass.
During glacial periods ice sheets have previously moved where? What has this done?
(Water cycle)
(Long-term changes in the water and carbon cycles)
Ice sheets move equator-wards, destroying masses of forest and grassland.
The area covered by vegetation, and water stored in the biosphere shrinks.
During glacial periods, how may climates change in the tropics?
(Water cycle)
(Long-term changes in the water and carbon cycles)
In the tropics, the climate becomes drier and deserts/grasslands displace masses of rainforests.
During glacial periods there are lower rates of what? What impacts does this have?
(Water cycle)
(Long-term changes in the water and carbon cycles)
Lower rates of evapotranspiration during glacial phases:
This reduce exchanges of water between the atmosphere, biosphere, oceans, and soils.
This (together with freshwater stored as snow and ice), slows the water cycle greatly.
There are dramatic increases and decreases in CO2 in the atmosphere. What happens to CO2 concentrations during peak glacial periods? What about interglacials?
(Carbon cycle)
(Long-term changes in the water and carbon cycles)
CO2 concentrations fell to 180ppm.
In warmer inter-glacial periods this increased to 280ppm.
Why may it be that CO2 concentration in the atmosphere be higher in interglacials, but lower in glacials?
This is possibly explained through the excess CO2 finding its way from the atmosphere into the deep ocean.
Changes in ocean circulation during glacial periods bring nutrients to the surface and stimulate phytoplankton growth.
Phytoplankton fix large amounts of CO2 by photosynthesis before dying, sinking to the deep ocean, storing the carbon.
The carbon pool in vegetation shrinks during glacial periods. Why?
This is because ice sheets advance and occupy large areas of the continent.
The carbon pool in vegetation shrinks during glacial periods, as ice sheets advance and occupy large areas of the continent. What does this cause?
This causes deserts to expand, tundra to replace temperate forests, and grasslands to encroach on tropical rainforests.
As much of the land is buried by ice, carbon stored in soils will no longer be exchanged with the atmosphere.
Expanses of tundra beyond the ice-limit, are able to do what?
Expanses of tundra beyond the ice-limit sequester huge amounts of carbon in the permafrost.
During glacial periods there is less vegetation cover, fewer forests, lower temperatures, and lower precipitation meaning what? What are the implications of this?
The total volume of carbon fixed in photosynthesis declines.
The implications are an overall slowing of the carbon flux - smaller amounts of CO2 returned to the atmosphere through decomposition.
