Atmosphere and Change
Describe the functioning of the atmospheric system in terms of the energy balance between solar and long wave radiation.
- Earth receives energy from the sun in the form of short wave solar radiation
- Not all short wave radiation is received from the Earth.
- The waves can also be reflected by the clouds or absorbed through.
- For the absorbed or cloudless radiations, the radiation reaches the crust.
- The brighter the surface, the more the solar radiation emitted back as long wave radiation.
- Long wave radiation is what is emitted from the Earth in response to the atmosphere (same radiation as the short wave radiation that is absorbed - but is released in the form of long waves).
- In a clear night, the long wave radiation will easily go passed the atmosphere.
- In a cloudy night, the long wave radiation will be trapped by the clouds.
- There is a balance in temperature and conditions as there is a "radioactive equilibrium” between the energy input and output.
Explain the changes in this balance due to external forcing (changes in solar radiation, changes in the albedo of the atmosphere and changes in the long wave radiation returned to space.)
Desertification
The impact of desertification can be dependent upon the type of sand. Very white sands have quite a high albedo whereas darker sands have a much lower albedo. Desertification caused by deforestation normally leaves dark sands/soils and therefore a low albedo with lots of radiation absorbed. However, it must also be remembered that vegetation produces shade which reduces the amount of radiation reaching the ground and therefore reduces ground temperatures. The processes of evaporation and transpiration can also reduce temperatures.
Melting Ice Caps
Melting ice caps and glaciers could change the earth's albedo drastically and increase the amount of incoming solar radiation absorbed. Pure white snow has one of the highest albedos (95%), if this replaced by water or rock then albedo is reduced and more incoming radiation absorbed, raising temperatures.
Particulates (pollution) in atmosphere
Pollution in the atmosphere can increase the amount of incoming radiation reflected, scattered and absorbed, therefore reducing the amount reaching earth. However, pollution can also change the albedo of surfaces like white snow, increasing the amount of incoming solar radiation absorbed by the earth.
Volcanoes
Large volcanoes can release massive amounts of ash into the atmosphere, increasing the amount being absorbed, reflected and scattered in the atmosphere, therefore reducing the amount reaching earth. However, volcanoes can also release large amounts of sulphur dioxide which is a greenhouse gas, therefore trapping in more outgoing solar radiation.
Cloud cover (artificial or natural)
Like with volcanoes and particulates increased cloud cover does reflect, scatter and absorb more incoming solar radiation in the atmosphere and prevent as much from reaching the earth's surface. However, it can also act as a blanket keep some outgoing radiation in the atmosphere.
Solar flares
Although solar activity from the earth changes it has no noticeable impact on the amount of incoming radiation. More damaging impacts can be to transport and communications (read article below).
Greenhouse gases
Greenhouse gases allow solar radiation into the atmosphere, but stop some outgoing radiation being released from the atmosphere and reflect it back to earth. This is increases the amount of radiation being absorbed by the earth and is known as the greenhouse effect (Transport, Animals (especially cows), burning fossils fuels (especially oil and coal), melting permafrost (methane is released when permafrost melts), industry and domestic use (wood fires) are all causes).
Deforestation
Like desertification, although soil may have a similar albedo to dark trees they do cool temperatures because they act as a source of shade and cool temperatures through evaporation and transpiration.
Discuss the causes and environmental consequences of global climate change.
Causes of Climate Change - Natural Causes
Milankovitch Cycles
Volcanic Eruptions
Human Causes
Greenhouse cases that creates the greenhouse effect
Carbon Dioxide
Consequences of Climate Change
Freshwater Availability
Seasonal sickness such as flu and allergies
Choking smoke
Mosquito menace
Desertification
The impact of desertification can be dependent upon the type of sand. Very white sands have quite a high albedo whereas darker sands have a much lower albedo. Desertification caused by deforestation normally leaves dark sands/soils and therefore a low albedo with lots of radiation absorbed. However, it must also be remembered that vegetation produces shade which reduces the amount of radiation reaching the ground and therefore reduces ground temperatures. The processes of evaporation and transpiration can also reduce temperatures.
Melting Ice Caps
Melting ice caps and glaciers could change the earth's albedo drastically and increase the amount of incoming solar radiation absorbed. Pure white snow has one of the highest albedos (95%), if this replaced by water or rock then albedo is reduced and more incoming radiation absorbed, raising temperatures.
Particulates (pollution) in atmosphere
Pollution in the atmosphere can increase the amount of incoming radiation reflected, scattered and absorbed, therefore reducing the amount reaching earth. However, pollution can also change the albedo of surfaces like white snow, increasing the amount of incoming solar radiation absorbed by the earth.
Volcanoes
Large volcanoes can release massive amounts of ash into the atmosphere, increasing the amount being absorbed, reflected and scattered in the atmosphere, therefore reducing the amount reaching earth. However, volcanoes can also release large amounts of sulphur dioxide which is a greenhouse gas, therefore trapping in more outgoing solar radiation.
Cloud cover (artificial or natural)
Like with volcanoes and particulates increased cloud cover does reflect, scatter and absorb more incoming solar radiation in the atmosphere and prevent as much from reaching the earth's surface. However, it can also act as a blanket keep some outgoing radiation in the atmosphere.
Solar flares
Although solar activity from the earth changes it has no noticeable impact on the amount of incoming radiation. More damaging impacts can be to transport and communications (read article below).
Greenhouse gases
Greenhouse gases allow solar radiation into the atmosphere, but stop some outgoing radiation being released from the atmosphere and reflect it back to earth. This is increases the amount of radiation being absorbed by the earth and is known as the greenhouse effect (Transport, Animals (especially cows), burning fossils fuels (especially oil and coal), melting permafrost (methane is released when permafrost melts), industry and domestic use (wood fires) are all causes).
Deforestation
Like desertification, although soil may have a similar albedo to dark trees they do cool temperatures because they act as a source of shade and cool temperatures through evaporation and transpiration.
Discuss the causes and environmental consequences of global climate change.
Causes of Climate Change - Natural Causes
Milankovitch Cycles
- If the Earth is more tilted then the summers are warmer. This means ice melts and does not build up in poles. If the Earth is less tilted, the summers are cooler so ice builds up the poles.
- Currently, we are at 23.5 degrees tilt in a 41,000 year cycle.
- According to milankovitch cycles, if you take out all the other factors, we should be in the middle of a cooling period which started 6000 years ago and will continue for the next 23,000 years.
- Sunspots are huge magnetic storms on the sun’s surface which release increased solar radiation to Earth.
- During the little ice age (1645-1715) a decrease in sunspot activity was recorded.
- Sunspots have been accurately recorded for over 400 years and an 11 year cycle has been identified.
- Solar variation could account for up to 20% of the warming experienced in the 20th century.
Volcanic Eruptions
- They have a short term effects (1-3 years) - cooling effect on the Earth’s atmosphere because they release sulfur dioxide into the atmosphere which increases atmospheric albedo (reflecting incoming solar radiation).
Human Causes
Greenhouse cases that creates the greenhouse effect
Carbon Dioxide
- Largest contributor to global climate change.
- Carbon dioxide parts per million (ppm) in the atmosphere have risen from 315 ppm in 1950 to 391 ppm in 2012 (more than 23% increase!).
- Expected to rise to 600 ppm by 2050.
- Second largest contributor to global warming.
- Increased by 1% annually.
- Increase size of population - cattle herds - demand for meat and dairy products to satisfy changing diets especially in LEDCs - leads to increase in emissions.
- Cattle convert 10% of food eaten into methane.
- Paddy fields also an important source and the increase in cultivation to meet increasing demand through population growth is a key reason.
- Likely to make a greater contribution in the future as permafrost melts releasing large quantities of methane hydrates.
- Increasing due to the sharp rise in the use of nitrogen fertilizers.
- At present the increase is calculated at 0.3% per annum.
Consequences of Climate Change
Freshwater Availability
- Climate change will make water security even more difficult to achieve
- Developing countries are coping with droughts and risk of flooding
- Coastal areas will be at risk due to increased flooding
- Death rate from disease associated with floods and droughts expected to rise in some regions
- Freshwater availability will decrease in Central, East and Southeast Asia by 2050
- Many African countries (population of close to 200 million people) are facing serious water shortages. By the year 2025, it is estimated that nearly 230 million Africans will be facing water scarcity, and 460 million will live in water-stressed countries
Seasonal sickness such as flu and allergies
Choking smoke
- Air quality declines from change in temperature
- Forest fries creates smoke
- Respiratory diseases
Mosquito menace
- Increase of malaria, better habitat for mosquitoes
- Dengue fever
- Breaking bone fever – causes blinding headaches, sever muscle and joint pains
- Many ecosystems will not be able to adapt to the unprecedented combination of climate change associated disturbances such as wildfires, and other aspects of modern-day global change
- 20-30% of species are likely to be at high risk of irreversible extinction if temperatures rises by 1.5-2.5 Celsius
- Huge changes in ecosystems will occur when average temperatures increase by 1.5-2.5 Celsius