If we fast-forward to 1700 when the global population had increased more than ten-fold, to 603 million. But a small global population overall meant there was little pressure on forests to make space for land to grow food, and as wood for energy.

The amount of land per person that was needed to produce enough food was not small – in fact, it was much larger than today. The global population at this time was small and growing very slowly – there were fewer than 50 million people in the world. Only 10% of this was lost in the first half of this period, until 5,000 years ago. The world has lost one-third of its forest – an area twice the size of the United States. 3 10,000 years ago 57% of the world’s habitable land was covered by forest. The bar chart just below shows the earth’s surface cover just after the end of the last ice age. I have therefore excluded these categories so we can focus on how habitable land is used. You see that of the 14.9 billion hectares of land on the planet, only 71% of it is habitable – the other 29% is either covered by ice and glaciers, or is barren land such as deserts, salt flats, or dunes. This is shortly after the end of the last great ice age, through to the present day. In the chart we see how the cover of the earth’s surface has changed over the past 10,000 years. How much forest has the world lost? When in history did we lose it? Humans have been cutting down trees for millennia. This is true for some problems, such as climate change.

Many people think of environmental concerns as a modern issue: humanity’s destruction of nature and ecosystems as a result of very recent population growth and increasing consumption.

Global cities over 10 million