This topic will provide an overview of climate change, including its causes, impacts, and the importance of addressing it through scientific research and policy measures.
Introduction to Climate Change
Key concepts, causes, impacts, and responses
| Term | Definition |
|---|---|
| Climate | Long‑term (≥30 years) average of temperature, precipitation, wind, etc., for a region. |
| Weather | Short‑term atmospheric conditions (hours to days). |
| Climate Change | A statistically significant alteration in the mean state of the climate or its variability, persisting for decades or longer. |
| Global Warming | The observed increase in Earth’s average surface temperature, primarily due to human‑driven greenhouse‑gas (GHG) emissions. |
Bottom line: Climate change includes global warming and changes in precipitation patterns, extreme‑event frequency, sea‑level rise, and ecosystem shifts.
| Gas / Factor | Radiative Forcing (W m⁻²) |
|---|---|
| CO₂ (current) | +2.1 |
| Methane (CH₄) | +0.5 |
| Nitrous oxide (N₂O) | +0.2 |
| Halocarbons | +0.3 |
| Aerosols (cooling) | –0.4 |
| Land‑use change | –0.1 |
| Feedback | Direction | Example |
|---|---|---|
| Water‑vapour feedback | Positive | Warmer air holds more water vapor → more IR absorption. |
| Ice‑albedo feedback | Positive | Melting ice reduces surface reflectivity → more solar absorption. |
| Cloud feedback | Complex (positive & negative) | Changes in cloud cover/type affect both reflection and trapping of radiation. |
| Carbon‑cycle feedback | Positive | Warming soils release more CO₂ and CH₄. |
| Sector | Primary GHGs | Representative Sources |
|---|---|---|
| Energy | CO₂ | Fossil‑fuel electricity generation, oil & gas extraction. |
| Industry | CO₂, N₂O, HFCs | Cement, steel, chemical production, refrigerants. |
| Transportation | CO₂, CH₄ (from fuel leakage) | Cars, trucks, aviation, shipping. |
| Agriculture | CH₄, N₂O | Enteric fermentation, rice paddies, synthetic fertilizers. |
| Land‑Use Change | CO₂, CH₄ | Deforestation, peatland drainage. |
| Waste | CH₄, CO₂ | Landfills, wastewater treatment. |
*Global share (2022, IPCC AR