And humanity has grown in activity. An impressive example is deforestation. Once upon a time, Earth's surface to a large extent was covered by forrests, dense forests in many areas that it was difficult for humans to actually dwell in them. A hypothethese states that, for example, four thousand years ago, the British Isles were covered with a forrest so dense that humans moved alongun the coasts to the North but did not explore the interior. The map shows the extent of the original forrests.

Today, large parts of the forrest are either gone and lost or heavily managed by humans. More than 50% of the forrest are gone (the brown areas in the lower left map) and the rest (shown in grey) are managed. Only 20% of the original forrest remain as what we call frontier forrest, and they are shown in green on the map. These frontier forrest are of very high value for the biosphere allowing for the undisturbed evolution of the ecosystems, but they are threatened by humanities pressure.