Bhai Jeevan Singh Ji(Bhai Jaita Ji) is one of the greatest Sikh of the Khalsa Panth. He wrote an amazing granth called 'Gur Katha' Granth. This granth has amazing knowledge about Rehit and about the way of life of a sikh.
In this Granth, there is a section called 'Ardaas'. In this 'Ardaas' section, in the 4th swaiya, Bhai Jaita Ji has made it clear that its the duty of every Sikh to be an environmentalist.
Below, I am writing the English Translation of the 4th Swaiya.
Swaiya
Bless the buffaloes O Lord and the cows, that nourish us with milk and satiate the soul.
Bless the cattle-keepers who toil with ten nails and yet make merry.
Bless thou the lakes, woodland, trees abloom with fruits and flowers sweet.
Sustain O Lord all nourishment, all cereal that upholds life aquatic, terrestrial and aerial.