[Is it natural to devastate the Earth - the only known place to live?]

The expansion of our civilization is a complex stress for the biosphere. The global warming supported by emissions of greenhouse gases can result in polar glaciers melting away, oceanic transgression and the destabilization of the climate, because conditions on Earth will move from the triple point of water. Moreover, we are polluting the environment by dangerous chemicals. Surprisingly, our behaviour is natural. Probably the first ecological catastrophe happened 3.1-2.5 billion years ago, when photosynthetic cyanophytes poisoned the originally anoxic oceans and atmosphere by oxygen and made most of the environment uninhabitable for competing anaerobous organisms. Now, humans predominate in the biosphere. We do not need to poisson any predators or concurrents. Homo sapiens sapiens should give up the archaic bacterial behaviour and should treat the neighbourhood more respectfully. The area of nature relatively untouched by people is getting smaller each year. The wilderness is more and more fragile to catastrophes, when its area decreases. Present situation of the global ecosystem is comparable with the situation preceding the biggest mass extinction in the history of metazoons at the paleozoic / mesozoic boundary. We should be careful.