The modern scientific understanding of global warming did not come from one person.

Some key figures were:

• Joseph Fourier (1820s) proposed that Earth's atmosphere traps heat.

• John Tyndall (1850s–1860s) showed that gases such as carbon dioxide and water vapor absorb heat.

• Svante Arrhenius (1896) calculated that increasing carbon dioxide from burning coal could warm the planet.

• Charles David Keeling (1950s onward) measured the steady rise of atmospheric carbon dioxide, producing the famous "Keeling Curve."

As for validation, the evidence today is very strong. Multiple independent measurements show:

• Global average temperatures have risen substantially since the late 19th century.

• Glaciers and ice sheets are shrinking worldwide.

• Sea levels are rising.

• Heat waves have become more frequent and intense.

• Carbon dioxide levels are higher than at any time in human civilization.

Major scientific organizations worldwide, including National Academy of Sciences, American Association for the Advancement of Science, and the Intergovernmental Panel on Climate Change, conclude that the Earth is warming and that human activities—especially the burning of fossil fuels—are the primary cause of most warming since the mid-20th century.

That does not mean every prediction has been perfect, but the basic claim that increasing greenhouse gases warm the planet has been repeatedly confirmed by observations over more than a century.