Environmental Risks of Economic Activity

• Soil erosion is topsoil being worn away by wind or water — made worse by deforestation, overgrazing, over-cultivation, population growth and over-abstraction of groundwater.
• Desertification is when semi-arid land degrades to become desert-like, caused by a vicious cycle of natural drought/rainfall extremes plus human overuse of the land.
• Global warming happens naturally (Milankovitch cycles, volcanoes, sunspots) but has been massively sped up by humans adding extra greenhouse gases — this is the "enhanced greenhouse effect."
• The enhanced greenhouse effect causes rising sea levels, more extreme weather, ecosystem shifts, and knock-on effects on health, farming, homes, and jobs.
• International agreements (Kyoto, Paris, COP) try to coordinate a global response through mitigation (reducing the cause) and adaptation (coping with the effects).
• Pollution comes in five flavours: air, water, land, visual, and noise — each with distinct sources, impacts, and management solutions.
• Resource conservation means using resources wisely now so they're still available later — through recycling, protected areas, quotas, laws, and individual behaviour change.
• Case study: the Pearl River Delta, China — a megacity region suffering acid rain, heavy metal contamination, and eutrophication from rapid industrial growth.

The core idea

Think of topsoil like the icing on a cake — it's thin, it's on top, and it's the part that actually has all the good stuff (nutrients) that plants need. Soil erosion is the wearing away of that topsoil by wind or water. It's a completely natural process — wind and rain have always moved soil around — but human activity strips away the soil's natural protection (tree roots, vegetation cover) and leaves it exposed, so erosion happens much faster than it would naturally.

The key thing to understand is that erosion isn't really about the wind or the rain themselves — it's about what's missing when they arrive. Roots normally hold soil particles together like a net. Leaves and canopy normally break the force of rainfall before it hits the ground (this is called interception). Remove the vegetation, and suddenly bare soil is sitting there completely exposed to whatever the weather throws at it.

Causes of soil erosion — and WHY each one works