Three quick suggestions to try for those looking for resources for small groups.
This is an excellent resource that has been developed by the Christian environmental charity, Operation Noah. Physical copies are currently out of stock but the videos are freely available on youtube and the study guide is available as a downloadable pdf.
This was originally written as a Lent group but is suitable for use by a small group at any time of year. It has been extremely well received and helps us to explore how we can approach the big issues facing our society through a Christian worldview.
This course, developed by Green Christian is the newest of the three. It invites us to imagine a new kind of society where both people and planet can thrive, and to find our place in the creation of this new future.