Natural processes are based on a number of principles.

1. Matter is neither created nor destroyed. Smoke going up the chimney does not disappear. It may be dispersed, but it is not destroyed.

2. All parts of the environment interact with other parts. Ultimately everything is connected. Impacts can be many thousands of kilometres from the source of pollution.

3. There is a lot of order in nature. As well as cycles, there are patterns, rhythms, waves, systems, universal molecules and structures. The seasons cycle. Snowflakes are never exactly the same but all have six-fold symmetry. We have developed mathematics to recognise, classify and exploit patterns.

4. The environment adapts to changes. Left long enough, some organisms will adapt or evolve to eat the most indigestible sludge. It may take a long time, and perhaps too long for us. 4000 million years have shown us that something will evolve to 'fit' the situation.

5. The "Balance of Nature" gives the impression of static balance. Yet no place in nature stands still. Everything is in constant change. Even when things look static, they are usually in dynamic equilibrium.

6. Ultimately there are limited resources on earth which means there is a "carrying capacity", although we do not really know what the limits are.