Alexander von Humboldt

Alexander von Humboldt's five-year expedition to South America (1799-1804) combined botanical, geological, meteorological, and geographical research in a manner that invented modern environmentalism and the concept of nature as an interconnected system. Darwin credited Humboldt's Personal Narrative as the primary inspiration for his own voyage on the Beagle. Humboldt's understanding that human activity could alter climate — expressed in 1800 — was 200 years ahead of its time.