Empires don't only fall to armies. They fall to the sky.

For ten thousand years, the weather has been the quietest and deadliest force in human history. A few degrees of warming built Rome. A few degrees of cooling starved dynasties, emptied cities, and toppled the mightiest empires on earth — and the people living through it almost never knew why.

Weather of Empire, Book Two of The Forces That Shaped Us, is the true story of how shifting climate built empires, toppled dynasties, and redrew the map of history.

Inside, you'll discover:

How the end of the Ice Age invented farming — and civilization itself

The centuries-long drought that destroyed the world's very first empire

The warm spell that let Rome conquer a continent — and the cooling that helped bury it

The "year without a summer" that starved two hemispheres and haunted a generation

How a single weather pattern — El Niño — helped kill tens of millions in the age of empire

This isn't abstract climate science. It's a gripping, human account of ice cores and grain harvests, of emperors and farmers at the mercy of a sky they couldn't read — and of what it means that, for the first time, we are the ones changing it.

Everything in these pages is true, drawn from the latest science and the oldest records.

If you love Jared Diamond, Sapiens, or Peter Frankopan's The Earth Transformed, you'll race through this — and can begin with Book One, Terrain of Empire.