The growth of the human population has resulted in a massive impact on the Earth based on data from the past decades and past century. Scientists call our present period the Anthropocene because the Earth's climate is clearly more affected by human activity than anything else. Carbon dioxide, created from a variety of human activities, has increased more rapidly, and is one-third higher, than at any time in the past 400,000 years.

This carbon dioxide increase, which traps heat in the atmosphere instead of letting it escape into space, is producing ocean water warming and climate change at an alarming rate. The rate of plant and animal species loss has become very high. What is especially alarming is that the rate of change is exponential, not linear. Things are getting ever rapidly worse in the near future, all due to the activities of a large and still growing human population.
skeptic.com: How We Know Global Warming is Real