Plus: unlike most other measures, we have 400 years of actual observation of the sun's activity. It takes some effort to translate the many ways it's been recorded, and it's not perfect, but the data is there. Climate scientists know the sun had an extended period of low activity through the late 1600s and early 1700s and can form hypotheses.

If we go through another, it's not a big shocker. It's an opportunity to test those hypotheses and develop a better understanding of the impact of solar cycles on the planet's climate. If they're wrong, it's not some grand indictment of climate science. It's just...science. But if they're right and we don't take measures to prevent the worst heating, then we might not get another chance until we recover from the floods and resource wars and the loss of knowledge.