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Causes for climate change - Coggle Diagram
Causes for climate change
Natural
Variation in solar output
Sun emits varying amounts of solar radiation due to the changes in magnetic field
Affects the earth's climate, which is very sensitive to the amount of solar radiation it receives
Sunspots
Sunspots are cooler regions of the sun's surface that appear as dark spots
Number of sunspots increase during period of intense solar magnetic activity
Results in higher solar radiation
Areas surrounding sunspots radiate more energy. which compensates for the lower temperature for sunspot areas
The number of sunspots rise and fall with an approximate 11 year cycle
Associated with the earth's cycle of high and low global temperatures
Volcanic eruptions
Ejection large volume of carbon dioxide, water vapour, sulfur dioxide, dust and ash
Chemical reaction between water and sulfur dioxide to form a sulfur based particle
Together with dust and ash they reflect the solar energy back into space
Cooling influence on regional and global temperatures
e.g. The eruption of Mount Pinatubo in the Philippines in 1991
Greenhouse effect
The natural process by which greenhouse gases trap heat in the atmosphere
Gases in the earth's atmosphere trap longwave radiation emitted from the earth's surface warming the atmosphere
Shortwave radiation is absorbed by the earth's surface which then heats up as a result
Greenhouse gases
Gases that are good absorbers of longwave radiation that are found in the atmosphere
When it absorbs longwave radiation, they re-radiate it in all directions
Incoming shortwave radiation from the sun passes through the atmosphere
Some shortwave radiation is reflected by the earth and the atmosphere
Most shortwave radiation is absorbed by the earth's surface which then heats up as a result
The warmed surface of the earth emits longwave radiation to the atmosphere
Greenhouse gases absorb longwave radiation, warming the atmosphere
Human involvement
Enhanced greenhouse effect
Increase in the concentration of greenhouse gases in the atmosphere, leading to a rise in global temperature
Caused by human activity where there is a higher rate in the release of greenhouse gases
Anthropogenic factors
The increase in the emission of greenhouse gases due to human activity
Deforestation
A loss in forest areas due to the removal and clearance of trees
Wood being used as a raw material to manufacture products like paper and building material
Clear area for mining activities, grazing animals, planting of crops and construction infrastructure
Soil is the largest source of carbon in the world where it is formed through the decay of organic matter
Soil exposure to sunlight which increases the soil temperature and the rate of carbon oxidation in the soil
The process where soil reacts with oxygen in the atmosphere to produce carbon dioxide
e.g.
In Singapore, between 2000 and 2010, 52000 square kilometres of forest was lost every year which means that everyday, 142.5 square kilometres of forest, equivalent to about four and a half times the area of Jurong island is lost
Mitigation
Many countries have planted new trees and imposed strict laws that restricts the number of trees can be felled
In China, India, Vietnam and the United States of America, have large-scale programmes to plant trees have added millions of hectares of new forests every year
Changing land use
Agriculture
The practice of cultivating land, producing crops and raising livestock
Farming devices like tractors run on fossil fuel
Inorganic fertilisers increases the amount of nitrous oxide in soil
Released when rain flows through the soil
Examples:
Cattle farming is the largest greenhouse gas emissions
Million tonnes of methane is released into the atmosphere as waste gas
Population of humans increase
Higher demand for agricultural and industrial land
Land is converted to urban or built-up areas as more people choose to live in cities
Contribute to greenhouse gas emissions as more fossil fuels are burnt
High carbon content
Examples:
Large consumers include China, United States of America, Canada and the United Kingdom
Industries
Production of goods and services within a country
Activities like manufacturing involve the burning of fossil fuels
Greenhouse gases are released by products when goods are produced