In Manhattan’s Union Square, mounted on a building home to a Best Buy and $8,000-a-month one-bedroom apartments, is a public art installation known as the Climate Clock. Between flashes of “Stop Fossil Fuels” and “Protect Earth,” the clock counts down—to the second—until the world is committed irreversibly to 1.5 degrees Celsius of warming. When the clock was first unveiled in September 2020, the world had about seven years and 100-odd days to act. When I visited this February, the countdown