Keep it Experiential, Embodied, and Playful
If you want to nurture future climate stewards, one of the most effective strategies you can take with younger learners is to encourage them to explore and appreciate nature! In his book, "Beyond Ecophobia: Reclaiming the Heart in Nature Education", the environmental educator David Sobel talks about the importance of exposure to nature at a young age, citing research that adults who spent a lot of time exploring the outdoors as kids exhibit more pro-environmental behaviors than those that did not. Kids who learn to love nature at an early age are more likely to protect it when they get older.
Play with children in the outdoors, and encourage parents to play with their children in the outdoors. Allow them to direct their own play, but narrate their play by describing what they are doing and asking them questions about what they are doing and why. Opportunities to play should be sustained over time, including returning to familiar places (e.g., a local park) at different points throughout the year.
Avoid using the words "be careful" and reveal your dislikes of certain aspects of nature (e.g., bugs, snakes). Children hear so many words of caution from adults when playing in nature, that they can start to fear nature. Let them get dirty or wet, and let them scrape their knees; they will be better climate stewards as a result. One possible alternative to saying "be careful" is reminding children to "pay attention," and supporting children to notice and manage risks, boundaries, and comfort levels during play.
Playfulness is an important approach to facilitated learning activities as well! Especially for young learners, games, songs, dances, and simulations can be helpful ways to explore complex climate science phenomena and concepts (e.g., the water cycle). Gestures and other embodied forms of learning and communicating are powerful tools for scientific modeling. You can encourage children to embody different plants, animals, water, and other components of ecosystems. For example, they might imagine and mimic how a polar bear would move, play, and care for its young.