It is an important principle of worship to not only listen to the seasons of the church but also the seasons of our society.  Worship should enable us to lift up our collective voices to God as we bring our major concerns to Him.  Currently there can be little doubt that there is major concern about the effect that we are having the environment.  The European Ecumenical council affirmed the desire of all the major denominations to focus our worship and prayer lives on Gods creation and our impact upon it annually.  This year the churches are setting aside 1st September to the 4th of October to focus on this.  As this is also the same time as many churches celebrate harvest it is probably a good time to do something in your church.