Twelve Earth Scientists in Order of Birth Year, Oldest First, From 1834 to 1946

Born in 1834, Powell led the 1869 expedition down the Green and Colorado rivers that made the first government-sanctioned passage through the Grand Canyon. He later served as the second director of the United States Geological Survey from 1881 to 1894, advocating western development policies grounded in careful environmental assessment.

Born in 1861, Nansen first became famous as a polar explorer, leading the first crossing of the Greenland interior in 1888. His science ranged from zoology and neuroscience to oceanography, and he received the Nobel Peace Prize in 1922 for refugee relief work.

Born in 1871, Jaggar was one of the scientists the United States sent in 1902 to investigate the volcanic disasters at La Soufriere and Mont Pelee, an experience he credited with inspiring his career in volcanology. He founded the Hawaiian Volcano Observatory and directed it from 1912 to 1940.

Born in 1891, Bergeron was a Swedish meteorologist of the Bergen School. In the 1930s he and Walter Findeisen developed the idea that clouds hold both supercooled water and ice crystals, so that most precipitation forms as droplets evaporate and accrete onto ice, a process now called the Bergeron process.

Born in 1897, Bjerknes was the son of the meteorologist Vilhelm Bjerknes. He helped develop the Norwegian cyclone model within the Bergen School, and earned a doctorate at the University of Oslo in 1924 for a paper on the dynamics of the polar front.

Born in 1898, Callendar was an English steam engineer who developed the theory linking rising atmospheric carbon dioxide to global temperature. In 1938 he was the first to show that land temperature had risen over the previous fifty years, an effect now called the Callendar effect.

Born in 1903, Hubbert was an American geologist and geophysicist who worked at the Shell research laboratory in Houston. He is best remembered for the Hubbert curve and Hubbert peak theory, a model of how the production rate of a finite resource such as oil rises, peaks and declines.

Born in 1915, Leopold was a leading American geomorphologist and hydrologist, and the son of the conservationist Aldo Leopold. He wrote Fluvial Processes in Geomorphology with Gordon Wolman and John Miller, and argued that water management should rest on geologic, geographic and climatic factors, not only economic and political ones.

Born in 1924, Press was an American geophysicist who advised four United States presidents. He served as Science Advisor to President Jimmy Carter from 1977 to 1981, and as president of the National Academy of Sciences from 1981 to 1993.

Born in 1931, Manabe is a Japanese-American physicist, meteorologist and climatologist who pioneered the use of computers to simulate global climate change. He shared the 2021 Nobel Prize in Physics with Klaus Hasselmann and Giorgio Parisi for physical modelling of Earth's climate.

Born in 1942, Katia Krafft was a French volcanologist and filmmaker who worked with her husband Maurice. Together they became pioneers in filming and recording volcanoes, often working within feet of active lava flows.

Born in 1946, Maurice Krafft was the youngest of the twelve, a French volcanologist and filmmaker. He and Katia died in a pyroclastic flow on Mount Unzen in Japan on 3 June 1991, and their archived footage later fed documentaries including Fire of Love.