I honestly don't care if climate change and pollution kills our planet. The universe will die of heat death eventually anyway, and I doubt future civilizations can harness the energy of collapsed stars.
"This is our harbinger. It brings good tidings.
"We will be dead when it reaches you. Our planet is dying. We do not have time to save ourselves. We only have time to ready ourselves, and to send a message.
"We have seen the signals from those who came before us. They were different, and we still don't really understand them. But if there were those who came before, there may be those who come after. It is in this hope that our harbingers travel.
"One has found you and learned your language so it can relay this message. Please listen.
"The galaxy is dark, and empty, and cold. It spins inevitably toward death. You will die too, one day. Perhaps you will have longer than we have. We hope so. But one day you too must vanish.
"Until that time, you must light the darkness. You must make the night less empty. We are all small, and the universe is vast. But a universe with voices saying "I am here" is far greater than a universe silent. One voice is small, but the difference between zero and one is as great as one and infinity.
"And when your time is passing, please send this message on, so the next voice can speak against the darkness."
-Message of a bygone alien civilisation to posteriority, SCP-1281