ast night on the radio, someone announced in a deep scary voice "… the cumulative impacts are now surpassing environmental threshold limits and development is no longer sustainable". "Yikes" I thought, and then wondered if anyone really understood the message.

When environmental organizations, professionals, scientists and politicians talk about protecting our environment, they use big terms like "cumulative impact", "threshold limits" and "sustainable development". If you research these terms, you will find that they have a lot of fancy definitions that often use even bigger and more confusing words. So, I thought we needed a translation.

"Cumulative impact" is simply the end result of many small actions. Although cumulative impacts can be both good or bad, the term is usually applied in the negative sense. Here's an experiment to help you understand.

Take a cup of water, and fill it to about 3 cm from the top. Place it on something that is precious to you, like your favourite wooden dining room table that has been handed down to you from previous generations. Now slowly put a small stone or marble inside the cup, one at a time. Each time you do this, observe the change. When you look at the cup from far away, there does not appear to be much change. However, when you look at the cup up close, you notice the impact of adding stones. Add a few more stones until the cup is almost full. Every time you add a stone there is a change in the water level. The end result of these series of minor changes is called the "cumulative impact".