Researchers find that shifts in Earth’s orbit can trigger abrupt climate changes, even in warm periods without ice sheets.

Climate can change fast, even when the planet looks stable. Earth has flipped into new patterns within decades in the past.

Regular readers of my column certainly know how to use the Big Dipper to find the North Star (aka Polaris). Some folks believe Polaris is important because it’s the brightest star in the heavens, and ...