They also took part in interactive sessions with Eco Schools and Size of Wales looking at the types of action young people can take – and ways to inspire others.
Fe wnaethon nhw hefyd gymryd rhan mewn sesiynau rhyngweithiol gydag Eco Ysgolion a Maint Cymru, gan edrych ar y mathau o gamau gweithredu y gall pobl ifanc eu cymryd - a ffyrdd o ysbrydoli eraill.