The geological history of the Earth bears the traces of many global climate changes. Variations in temperature, radiation levels and the composition of the planet's atmosphere have proved to be a verdict for some species and an evolutionary impetus for others. Some major extinctions wiped out up to 90 percent of the species of that time, bringing life on the planet to the brink of extinction. Over the last 500 million years there have been five such global catastrophes, and right now according to statistics a sixth one is in progress, and the fastest known in terms of running its course. What is happening on our planet and why is its biosphere degrading so rapidly? Let's try to find out.