Global Warming

Global Warming

What Is Global Warming?

Global warming is the gradual increase in Earth’s average temperature, mainly caused by the buildup of greenhouse gases in the atmosphere.

💡 Key Concept: Human activities release greenhouse gases like carbon dioxide and methane, which trap heat and cause climate change.

 

The Greenhouse Effect (Simplified)

1️ The Sun emits short-wave radiation which enters Earth’s atmosphere.
2️ Earth’s surface absorbs this energy and re-emits it as long-wave (infrared) radiation.
3️ Greenhouse gases absorb and re-radiate this heat – warming the Earth.

 

Main Greenhouse Gases

Gas

Source

Carbon dioxide (CO₂)

Burning fossil fuels (cars, power stations), deforestation

Methane (CH₄)

Cattle farming, rice fields, landfill sites

Nitrous oxide

Fertilisers, vehicle engines

 

Causes of Increased Greenhouse Gases

✔ Burning fossil fuels (coal, oil, gas)
✔ Deforestation (less CO₂ absorbed by trees)
✔ Agriculture (especially cattle and rice farming)
✔ Waste disposal (landfills release methane)

Consequences of Global Warming

Impact

Effect on the Planet

Rising sea levels

Flooding of low-lying areas and habitats

More extreme weather

Heatwaves, storms, droughts, floods

Loss of biodiversity

Species extinction as habitats change or disappear

Changes in species distribution

Organisms move to cooler areas or become endangered

Threats to food security

Droughts and changing rainfall patterns affect crops

💡 These effects are already being observed in many ecosystems.

What Can Be Done?

✔ Reduce fossil fuel use – use renewable energy
✔ Plant more trees (carbon sinks)
✔ Eat less meat – reduce methane emissions
✔ Improve energy efficiency
✔ Increase awareness and global cooperation

Questions 

  1. What causes global warming?
  2. Name two greenhouse gases.
  3. How does deforestation contribute to global warming?
  4. What are two consequences of rising global temperatures?
  5. Suggest one way to reduce global warming.

Summary 

  • Global warming is caused by increased levels of greenhouse gases, especially CO₂ and methane.
  • It leads to climate change, habitat loss, and rising sea levels.
  • Actions such as reducing emissions, planting trees, and changing lifestyles can help slow the effects.