Pope Francis, riding a wave of mostly positive reaction to his encyclical on ecology, on Monday set up a Catholic “World Day of Prayer for the Care of Creation” to draw attention to the plight of the planet.

The day, to be marked by the world’s 1.2 billion Roman Catholics each year on Sept. 1, is Francis’s latest move to try to highlight global environmental concerns ahead of a pivotal U.N. summit on climate change in Paris in December.

“As Christians we wish to contribute to resolving the ecological crisis which humanity is presently experiencing,” Francis said in a letter to two Vatican cardinals whose departments are involved in issues of justice, peace and Christian unity.

Sept. 1 is also when Orthodox Christians mark their day for the protection of the environment, giving the gesture added symbolism in relations between the Eastern and Western branches of Christianity.

Francis said the day, to be marked with events in every Catholic diocese around the world, would offer Catholics “a fitting opportunity to reaffirm their personal vocation to be stewards of creation”.

Francis said it would also be a chance to “thank God for the wonderful handiwork which he has entrusted to our care, and to implore his help for the protection of creation as well as his pardon for the sins committed against the world in which we live”.

In June, the pope issued an encyclical on climate change, the first ever dedicated to the environment. The call to his church’s members could spur the world’s Catholics to lobby policymakers on ecology issues and climate change.

He has said he wants the encyclical and other Church initiatives to influence the U.N. Paris summit in December, the purpose of which is to reach a global agreement to combat climate change after past failures.

Last month, at a Vatican-hosted conference of mayors and governors from major world cities, Francis urged the United Nations to take a “very strong stand” on climate change at the summit.