The primary grades are a wonderful time for foundational work on climate change, Noah. Fortunately, Next Gen Science Standards give us a guide for age-appropriate learning goals for each level. I have pulled out all of the goals related to climate change, and categorized them by grade level, K-12. See link below for Climate Change & NGSS. As you'll see, the focus in the primary grades is on developing a basic understanding of nature, and how one thing can have an impact on another; for example, a change in habitat affects those who live there. As with every grade, it's important that children know that there are many ways we can help protect nature. For more ideas, visit the Start Learning page on Kids Against Climate Change.
Climate Change & NGSS
Kids Against Climate Change