Causes of climate change

Question 1

Natural Cause - Volcanic Eruptions

Answer 1

• Volcanic eruptions release gases, dust, and ash.
• Initially, these emissions cause short-term cooling by reflecting sunlight.
• Sulphur dioxide (SO2) transforms into sulphuric acid aerosols in the stratosphere, leading to significant cooling up to a year later.
• This can result in a “volcanic winter” lasting for several years and affects global temps.
• Mount Tambora in 1815 caused a “year without a summer,” causing crop failures and famine.
• While CO2 is emitted during eruptions, its long-term climate impact is considered insignificant, potentially causing short-term warming in some cases.

Question 2

Natural Cause - Solar Variation:

Answer 2

• Natural solar energy fluctuations impact Earth’s climate.
  The sunspot cycle involves 11-year variations in sunspot occurrences.
• Sunspots are massive magnetic storms on the sun’s surface.
• Sunspots emit increasing solar energy variations.
• High sunspot periods lead to temporary Earth warming.
• Low sunspot periods can induce cooling effects.

Question 3

Anthropogenic cause - Agriculture

Answer 3

• Agriculture contributes 20% of global human-caused greenhouse gas emissions.
• Methane and nitrous oxide emissions from rice cultivation and livestock rearing.
• Rice cultivation increased globally, producing methane due to flooded fields.
• Livestock is responsible for 29% of methane, 9% of CO2, and 65% of nitrous oxide emissions globally.
• In Australia, livestock accounts for 70% of agricultural greenhouse gas emissions, third-largest emitter after energy and transport, contributing to 13% of the nation’s total emissions.

Question 4

Anthropogenic cause - Deforestation

Answer 4

• Deforestation: Clearing native forests for purposes like timber, agriculture, urban development, or mining.
• Agriculture, Southeast Asia, responsible for 80% of rainforest biome loss.
• Approximately 4.8 billion tons of CO2 are released annually due to the global loss of tropical forests.
• Developing countries like Indonesia use “slash and burn” methods, intensifying CO2 emissions from deforestation.
• alters evapotranspiration and albedo, reduces rainfall and increases surface reflectivity, causing climate changes.