Doing civic science is not for everybody. It is a calling where there needs to be a rapport between you and your audience. You need to speak their language. What you have to say is not for everybody. Joe and Jane Farmer in cosmology may just be too hard a sell, although why the night sky isn't bright might work.
Most people are willing to have faith that scientists know what they are doing.
Keep it simple. We who are addicted to precision in terminology and expression, along with the ifs and buts and caveats of a detailed argument, can quickly lose our audience in a welter of detail. But a simple ice cube analogy can show why warming that melts the west Antarctic ice cap would cause global flooding. The audiences may be literate, though not literate in science. Be clear on what your message is and what connection hooks it to some matter of general public interest with which people identify.