For thousands of years, the single species Homo sapaiens, to which you and i have the dubious honor of belonging, has been increasing in numbers.
in the past couple of centuries, the rate of increase has itself increased exprosively. At the time of Julius Caesar, when Earth's human population is estimated to have been 150 million, that population was increasing at a rate such that it would double in 1,000 years if that rate remained steady.
Today, with Earth's population estimated at about 4,000 million (26 times what it was in Caesar's time), it is increasing at a rate which, if steady, will cause it to double in 35 years. Thw present rate of increase of Earth's swarming human population qualifies Homo sapiens as a n ecological cancer, which will destroy the ecology just as sure as any ordinary cancer would destroy an organism.