"Studies have shown that congregations where pastors talk about climate change have people who are more likely to engage in taking care of creation and to advocate for climate solutions." See the video below.
It is good to care about the Earth, but there is a great deal of debate about climate change and if it is caused by humans. The ELCA has decided it is.
But beyond that, why isn't the ELCA encouraging people to believe in the Lord Jesus Christ for the forgiveness of their sins? You don't hear that message, and it is of utmost importance. Life on Earth is certainly important, but this is how we have true life now and eternal life in heaven.
Here is an environment page on ELCA.org where the video can also be found.