The same moments you would find on any dated timeline, sorted the other way around — by the issue they belong to instead of the day they happened. Pick a problem your students already argue about, then follow it backwards through time.
Issues
1
Entries
3
Start here
Each issue gathers its own moments, oldest first, so a class can watch a problem take shape instead of memorizing a list of years.
Issue
What the fight is about
Coal, oil, and gas put carbon dioxide into the air, and carbon dioxide holds heat. Scientists worked that out more than 150 years ago, and the world has been arguing about it ever since — about who should burn less, who should pay for the damage, and how quickly anything has to change. The argument is not about whether the warming is real. It is about cost, responsibility, and time. The entries below are moments when that argument became visible to everyone.
Three years before the experiment usually credited with the discovery, an American scientist and women's rights activist named Eunice Newton Foote filled glass tubes with different gases and measured how warm they got. Carbon dioxide warmed the most.
Swedish chemist Svante Arrhenius calculated in the 1890s that burning coal and other fossil fuels would slowly warm the planet. On October 15, 1902, an Alabama newspaper turned his careful arithmetic into a short, alarming notice — proof of how early the warning reached the public.
On a sweltering June day in 1988, NASA scientist James Hansen testified before a U.S. Senate committee that human-made warming had already begun. The hearing pushed climate change onto front pages and into public debate.
How these entries are made
Written by us
Each description is written in the History Education Foundation's own words — never copied from another organization's site.
Traced to a source
Every entry names where the information came from, and original text is quoted only when it is old enough to be in the public domain.
Built for a classroom
Each entry ends with a why-it-matters question you can put on the board tomorrow morning.