What is the Greenhouse Effect?
The greenhouse effect is a natural phenomenon that warms the Earth’s surface. When the Sun’s energy reaches the Earth’s atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases (GHGs).
Without this natural greenhouse effect, the average temperature on Earth would be about -18°C instead of the current +15°C. In other words, life as we know it would not exist.
The Additional Greenhouse Effect
The additional greenhouse effect is 100% human-made. Since the industrial revolution, burning fossil fuels (coal, oil, gas) has released enormous quantities of greenhouse gases into the atmosphere, amplifying the natural greenhouse effect.
CO₂ concentration in the atmosphere has increased by 51% compared to pre-industrial levels, rising from approximately 280 ppm to over 420 ppm today. This is unprecedented in at least 800,000 years of Earth’s history.
Main Sources of Additional Greenhouse Gases
- Fossil fuel combustion — burning coal, oil, and natural gas for energy, transport, and industry
- Deforestation — destroying forests that absorb CO₂, while releasing stored carbon
- Agriculture — methane from livestock and rice paddies, nitrous oxide from fertilizers
- Industrial processes — cement production, chemical manufacturing, and other industrial activities
Consequences of the Intensified Greenhouse Effect
The intensified greenhouse effect causes global temperatures to rise, leading to a cascade of environmental impacts:
- Rising sea levels due to thermal expansion and melting ice sheets
- More frequent and intense extreme weather events (heatwaves, floods, droughts)
- Ocean acidification threatening marine ecosystems
- Disruption of agricultural patterns and food security
- Loss of biodiversity as species struggle to adapt
🔑 Key Takeaways
The increase in GHG concentration comes from human activities, primarily fossil fuel combustion and deforestation. This intensified greenhouse effect causes global temperatures to rise, with far-reaching consequences for our planet and our economies.
What’s Next?
Now that you understand the greenhouse effect, learn how businesses measure and account for their emissions in the next course: GHG Accounting: Methodologies & Scopes.