Numbers Don't Lie: 71 Things You Need to Know About the World

by Vaclav Smil

For years I have tried to imagine how Earth would appear to a comprehensive and discerning probe dispatched by wonderfully sapient extraterrestrials.

The best available estimate of the continent’s maximum carrying capacity (including smaller-size forest elephants) was about 27 million animals at the beginning of the 19th century; their actual number might have been closer to 20 million. Today, though, there are well under a million.

Assuming, conservatively, an average embodied rate of 0.25 gigajoules per phone, 4.5 gigajoules per laptop, and 1 gigajoule for a tablet, the annual production of these devices requires about 1 exajoule (1018 joules) of primary energy—that is, roughly equal to total annual energy use in New Zealand or Hungary.

According to the 2018 study by the Intergovernmental Panel for Climate Change, the only way to keep the average world temperature rise to no more than 1.5°C would be to put emissions almost immediately into a decline steep enough to bring them to zero by 2050. That is not impossible—but it is very unlikely.