Monitoring changes to the global cycles

Why is accurate monitoring of the carbon and water cycle necessary?

Due to the potentially damaging effects of climate change

What are the main ways the carbon and water cycle are monitored?

Satellites, remote sensors using Geographic Information System technology (GIS) this data can be mapped to show trends, anomalies and change

What are the diurnal changes in the carbon and water cycle?

• In the water cycle, lower temps at night, lowers the rate of evapotranspiration.

• Convectional precipitation, dependent on direct heating of the ground surface by the Sun, is a daytime phenomenon often falling the afternoon when temperatures reach a max. This is significant from convectional storms.

• Flows of CO2 also vary as in the daytime CO2 flows from the atmosphere to vegetation. At night this flux is reversed as without sunlight, vegetation and phytoplankton in the oceans lose CO2.

How are seasonal changes monitored?

• Seasons are controlled by variations in the intensity of solar radiation. In the UK, solar radiation peaks mid-June, to around 800 W/m2; in December it falls to 150 W/m2

• Evapotranspiration is highest in the summer months and lowest in the winter.

• In the driest parts of England’s lowlands lose 80% of precipitation to evapotranspiration

How are month-to-month changes monitored?

• In the middle to high latitudes, day length or photoperiod, and temperatures drive seasonal change.

• In the tropics, water availability is the main causes of seasonal change.

• When trees are in full foliage, there is a net global flow of CO2 from the atmosphere to the biosphere causing CO2 levels to drop by 2 ppm

• The flow is reserved at the end of summer with natural decomposition releasing CO2 back into the atmosphere. This occurs in temperate forests which extract a lot of CO2.

• In the oceans, phytoplankton are stimulated into photosynthetic activity due to rising temps, more intense sunlight and lengthening photoperiod. The North Atlantic algae blooms from March to mid-summer.

What is the long-term impact on the water cycle?

• Sea level worldwide falls by 100-130m during glacial periods.

• Ice sheets and glaciers expand to cover around 1/3 of land mass

• This leads to the destruction of vegetation and shrinkage of the biosphere

• The tropics become drier and deserts and grasslands displace large areas of rainforest

• Lower rates of evapotranspiration during glacial phases reduces water exchanges between the atmosphere and oceans, biosphere and soils

• Freshwater stored as snow and ice slows the water cycle down.

What is the long-term impact on the carbon cycle?

• During glacial periods CO2 levels dropped dramatically - 180 ppm (100 ppm higher interglacial periods)

• Most CO2 is found in the ocean circulation brings nutrients to the surface and stimulate phytoplankton growth, which fixes large amounts of CO2 before dying and sinking to the deep ocean. Lower ocean temps also making CO2 more soluble in the surface

• Carbon store in vegetation on falls (no soil exchange)

• Permafrost stores CO2 - slowing CO2 fluxes

How is arctic sea ice monitored and why?

• A collection of satellites has provided a continuous map of the Earth’s sea ice cover. It measures energy from the Earth’s surface

• Key indicator of climate change - less sea ice, stronger storms are possible and the impact of feedback loops

How is arctic ice caps/glaciers monitored and why?

• NASA ice, cloud and land Elevation Satellite 2 is a photon-counting laser that allows scientists to measure the elevation of ice sheets, glaciers etc.

• Rates of ablation can be tracked - atmosphere is becoming warmer/cooler; measures surface height of ice sheets and glaciers - shows the extent of change in the volume of ice

How is water vapour monitored and why?

• This is measured in situ by balloon and aircraft-based instruments. Passive microwave sensors installed on polar orbiting platforms.

• Its a greenhouse gas and its condensed forms exert a profound influence on solar insolation

• Can also help highlight rates of photosynthesis, total precipitation

How is deforestation monitored and why?

• Satellites capture images of the Earth on a daily basis. The best images from a given month are stitched together into a mosaic - give a clear picture of the surface coverage

• Number of trees - rate of photosynthesis impacts the carbon cycle and land use changes

How is atmospheric CO2 monitored and why?

• Measures through a CO2 sensor that measured the infrared light which is absorbed by CO2 molecules

• Provides insight with NASA’s Orbiting Carbon Observatory 2 - highlights the impact of human activities on Earth’s Climate.

How is NPP ice monitored and why?

• This tracks the growth of terrestrial vegetation over 8 days

• Both the water and life on Earth relies directly or indirectly