2.5. How do scientists know that recent climate change is caused by human activities?

First read pages 5-6 of the document CCE&C and pages 5-6 of the document WWK and then watch the video, “Introduction to Climate Science” (https://www.youtube.com/watch?v=zx_oY92W2JY) by San José State University’s climate scientist Eugene Cordero which supplies an overview of indicators of a warming world and the numerous factors that influence the climate system. After watching this video respond to these questions in the Lesson 2 Response Form.

• How can we tell which factors are the most important?
• What evidence does the narrator give for scientific consensus about human contributions to climate change? 
• What are three lines of evidence that have convinced scientists and scientific organizations that humans are causing climate change? 
• What have you heard about climate climate in the popular media?
• Is human-induced climate change presented as a scientific consensus, or an open debate that’s still up for question? 

Watch the brief “Consensus Sense”  (http://whatweknow.aaas.org/consensus-sense) video from the American Association for the Advancement of Science (AAAS) Use this question to guide your thinking: What arguments do the scientists featured in this video make for moving beyond a debate about the causes of climate change?