I had used the word in this context and in lower case:
“…using the power of all forms of communication to tell the story of a new way of thinking about our relationship to the earth and the future.”
A kind editor, who is a PhD ecologist, suggested that to use the lower case was “a subtle but ubiquitous way to de-emphasize our home planet.” I think I agree with him, but wondered what the strict grammarians would say.
Depends on who you ask to some degree. Earth as soil is agreed on as lower case. But…
The problem with the word “earth” is that it, along with a number of other words, can be used as both a common noun and a proper noun. The use of “earth” to refer to soil, ground, or land is almost certainly a common noun and should not be capitalized unless it is at the beginning of a sentence. “Earth” to indicate a place, however, is somewhat more complicated. In general, if “earth” is being used to refer to the planet, but is not being used in an astronomical context, it should be written lowercase.
So: would you leave my sentence as written, or yield to the upper-case version to honor the Planet planet as has been suggested?