D4.3A Causes of climate change, feedback and habitat change

Climate change today is driven mainly by human activity

1. Climate change is driven by both natural factors and anthropogenic (human-caused) factors.
2. Recent warming is dominated by anthropogenic release of greenhouse gases, mainly carbon dioxide (CO₂) and methane (CH₄), which trap heat and intensify the greenhouse effect.

Human CO₂ mostly comes from burning carbon that was locked away

1. Burning fossil fuels: coal, oil, and natural gas are the primary anthropogenic source of CO₂.
   1. These fuels power energy production, transport, and industry.
   2. Combustion releases carbon stored in the fuel into the atmosphere as CO₂.
   3. Coal power plants and petrol vehicles are everyday examples of large CO₂ emitters.
2. Deforestation: clearing forests for agriculture, urban development, or logging is another major CO₂ source.
   1. Trees absorb CO₂ during photosynthesis, so removing them releases stored carbon back into the atmosphere.
   2. Losing trees also reduces the Earth's future capacity to absorb CO₂.