Shortly after the end of the last great ice age — 10,000 years ago — 57% of the world’s habitable land was covered by forest. That’s 6 billion hectares. Today, only 4 billion hectares are left. The world has lost one-third of its forests, an area twice the size of the United States. Only 10% of this was lost in the first half of this period, until 5,000 years ago. The turn of the 20th century is when global forest loss reached the halfway point: half of total forest loss occurred from 8,000 BCE to 1900; the other half occurred in the last century alone. Deforestation is not a new problem: relatively small populations of the past were capable of driving a large amount of forest loss. But deforestation accelerated over the last century, driven by the continued expansion of land for agriculture. Urban land accounts for just 1% of global habitable land. The world passed “peak deforestation” in the 1980s, and it has been on the decline since then. Improvements in crop yields mean the per capita demand for agricultural land continues to fall. Since 1961, the amount of land we use for agriculture has increased by only 7%. Meanwhile, the global population has more than doubled, from 3.1 to 8 billion. This means that agricultural land per person has more than halved. There are real reasons to believe that this century doesn’t have to replicate the destruction of the last one.