James Croll

Born in Perthshire, Scotland, in 1821, James Croll was largely self-educated and came from a modest background. Before becoming known for his scientific work, he held a wide range of jobs, including millwright, tea merchant, insurance agent, and hotel keeper. Despite poor health and limited formal schooling, he developed a deep interest in physics, astronomy, and the natural world.

Croll is best remembered for his work on climate change and the Ice Ages. In the nineteenth century, he argued that variations in Earth’s orbit and related astronomical cycles could drive major changes in climate. Although later scientists revised parts of his theory, his big idea—that orbital changes play an important role in long-term climate patterns—was a major step forward and helped lay groundwork for later research.

He eventually worked with the Geological Survey of Scotland and was elected a Fellow of the Royal Society, a remarkable achievement for someone who had come to science by such an unconventional route. He died in 1890, but his reputation has grown over time as historians of science and climate researchers have recognized how original and influential his thinking was.