This is a very limited timeline focused on significant milestones; for more in-depth timelines, please see A Climate Chronology (University of Maine) and The Discovery of Global Warming (from the American Institute of Physics).
Severe droughts precipitated the exodus of early humans from Africa
Climate observations date back to ancient Greece and Rome
Aristotle, Hippocrates, and Plato spoke about droughts and subsequent famine due to extreme weather events
Scientists theorize that abrupt climate change contributed to the fall of the Maya civilization
The 1800s/Beginning of the Second Industrial Revolution
1816- The Year Without a Summer
•Famine: particulates from the explosion of Krakatoa blocked sunlight
•Disease: Drought, then flooding, caused mutation in cholera bacteria in the Bay of Bengal; spread from Asia because none were resistant to the new strain
•1824- Joseph Fourier
•Discovered the process whereby gases in the atmosphere trap the sun’s heat and coined the term “greenhouse gases”
•1860s- John Tyndall
•Measured the capacity of water vapor and CO2 to trap infrared light
•1896- Nobel Prize winner Svante Arrhenius was the first to calculate human-driven contributions (through coal-burning) to the “greenhouse effect”, a term that he coined
1957- Roger Revelle (Scripps Institution of Oceanography) and Hans Suess (U.S. Geological Survey) discovered the chemical pathways of ocean CO2 uptake. Findings showed they had limited ability to absorb the CO2 released through burning fossil fuels. Refinement of their calculations hasn’t changed the basic conclusion.
•1965 President Johnson said publicly,"[t]his generation has altered the composition of the atmosphere on a global scale through ... a steady increase in carbon dioxide from the burning of fossil fuels."
•In 1969 Senator Daniel Patrick Moynihan was warning of a dangerous sea-level rise of 10 feet or more. "Goodbye New York" he said. "Goodbye Washington.”
•“Over a ten-year horizon, extreme weather and climate-change policy failures are seen as the gravest threats.”
•from The Global Risks Report (World Economic Forum) 2019
Resources are continually updated, with the most recently-published placed at the top.
•East African megadroughts between 135 and 75 thousand years ago and bearing on early-modern human origins- PNAS October 16, 2007 104 (42) 16416-16421.
•Climatic change as a topic in the classical Greek and Roman literature. Climatic Change 7, 441–454 (1985).