1. This is true 2. Solar output is at one of its minimums 3. "abrupt" in that case means over the course of decades or centuries, not a few years. Re-read that Nature article, it doesn't say what you think it says. 4. Definitely, Earth will be fine, humans not so much. There are plenty of times in the past few hundred million years where humans would have a rough, or impossible, time surviving. 5. Yes 6. Yes 7. Denier or not, you need to read more, starting with the article you linked.