More people are at risk of natural disasters than ever before -- and much of it is our own fault for continuing to build where nature says not to.

Atlas of the Human Planet outlines human exposure worldwide to six major natural hazards: earthquakes, volcanoes, tsunamis, tropic cyclone winds, tropical cyclone storm surge, and floods. Because cities in disaster-prone areas keep growing, global exposure to major catastrophes doubled between 1975 and 2015. The findings will be used to identify effective policy actions to help communities become more resilient against natural disasters.

The hazards that threaten the greatest number of people are:

Earthquakes, which pose a threat to up to one third of the world's population;

Tropical cyclones, which destroy homes in almost 90 countries;

Flooding, which affected around 1 billion people in 155 countries; and

Volcanoes. The 220 most dangerous volcanoes directly threaten more than 400 million people.

The largest number of people are exposed to earthquakes, and because of urban growth on or near fault lines, people living in seismic areas increased by 93% since 1975. Tsunamis, a consequence of earthquakes, affect coastal areas in many regions as well, with the most dangerous areas concentrated in Asia. The highest amount of built-up surface (buildings and other developments) exposed to tsunamis is in Japan, followed by China, and then the United States.

Floods are the most frequently occurring natural disaster, with exposure highest in Asia, which has 77% of the world's 1 billion at-risk people. Tropical cyclone winds now pose a threat to 1.6 billion people in 89 countries, up from 1 billion in 1975, with the most built-up surface exposure in China and Japan.