"It's Part of a Natural Cycle"
While that statement is partially correct, one must look at it more specifically. Yes, climate has changed before, but not in the way that it is currently. Some believe that the Earth's rapid climate increase is part of a natural cycle. This means that if it was cold for some time, it then has to heat up again. While scientists say that it is possible that Earth has a natural climate cycle, the scientific community does not know enough about it to solely attribute this extreme global warming to it. Scientists do know that Earth's climate behaves sort of like Newton's law - an object in motion or at rest will stay in that state until another force acts on it. Similarly, the Earth will remain at a steady climate until something compels it to grow cooler or warmer. In this case, many forces (almost all anthropogenic) are causing the planet's climate to increase. Right now, humans are the ones causing the change, not nature's natural cycle. Thus, nature is not adapting adequately to such change. Additionally, it is the way and rate that the climate is changing that is so unhealthy for the environment, not simply the fact that it is changing. The rate is too fast for organisms to adapt, causing mass extinctions across the globe. No known natural forces result in the way that climate has been changing, except for the anthropogenic contributions over the past few years. While in the past, yes, climate has changed due to natural cycles, scientists agree that the way in which this 'cycle' is progressing is caused by humans and is far more unhealthy than any other cycle in the past.
Barry, Patrick L. 20 October 2000. "Earth's Fidgeting Climate." NASA Science News. Accessed 16 October 2017.
Cook, John. 17 July 2015. "Human fingerprints on climate change rule out natural cycles." Skeptical Science. Accessed 15 October 2017.
Dash, Jan, and Cook, John. 2017. "Climate Science Glossary." Skeptical Science. Accessed 16 October 2017.
Contributed by: Ateret Frank, Alleigh Keyes, & Sam Luitjens