6) Human activities are impacting the climate system.
![A satellite image of Florida, showing a plume of smoke from a large brush fire. A satellite image of Florida, showing a plume of smoke from a large brush fire.](http://ncse.com/files/images/Florida_misr.img_assist_custom.jpg)
The sixth principle is based on the overwhelming evidence, accumulated and assessed by the scientific community for over half a century, that human activities are affecting climate on a global scale. Particularly noteworthy is the increase of atmospheric gases, such as carbon dioxide, methane, nitrous oxide and certain artificial chemicals (including chlorofluorocarbons, for example), that trap outgoing infrared heat, leading to a warming of the atmosphere.
While many who deny the consensus of climate science cast doubt or all together dismiss the multiple lines of evidence that confirm that human activities are affecting climate and the Earth’s ecosystems, there in no doubt in the minds of the scientists who study climate and publish in peer-reviewed climate science journals.
CLEAN’s “Teaching Essential Principle 6” provides overview of the content, why it is important, related pedagogical challenges, and examples of high quality resources by grade level.
Continue to the next section to find out how climate change will have consequences for the Earth system and human lives.