Sustainability: definition with simple natural science

I don't know why you'd need a fancy, French guy telling you what sustainable development is. It's development that can be sustained.

See, simple as can be.

Actually, the definition that Alex (sp?) gives - sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs - works really well. He does go on a bit to explain this in more scientific (thermodynamics, law of conservation of matter, photosynthesis) terms and to explore a few of the root causes of unsustainability.

The four causes of unsustainability...

• Relatively large flows of materials from the Earth's crust (mining, drilling)
• Accumulation of substances created by society (CO₂, polymers, trash)
• Physically inhibit nature's ability to run cycles (deforestation, paving over grass)
• Barriers to people meeting their basic needs worldwide (economic inequality)

The above video is posted on the Sustainability Illustrated website alongside a BUNCH of other videos. It's only an introduction to the topic, and his other videos go into much more detail on the topic.