Science!

When did scientists first warn humanity about climate change?

John Tyndall's setup for measuring radiant heat absorption by gases, via Wikimedia Commons

All a Commie plot, obvs. Since the ancient Greeks, even.

Scientists first began to worry about climate change toward the end of the 1950s, Spencer Weart, a historian and retired director of the Center for History of Physics at the American Institute of Physics in College Park, Maryland, told Live Science in an email. "It was just a possibility for the 21st century which seemed very far away, but seen as a danger that should be prepared for."

The scientific community began to unite for action on climate change in the 1980s, and the warnings have only escalated since. However, these recent warnings are just the tip of the melting iceberg; people's interest in how our activities affect the climate actually dates back thousands of years.

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The ancient Greek debates were among the first documented climate change discussions, but they focused only on local regions. It wasn't until a few millennia later, in 1896, that Swedish scientist Svante Arrhenius (1859-1927) became the first person to imagine that humanity could change the climate on a global scale, according to Weart. That's when Arrhenius published calculations in The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science showing that adding carbon dioxide to the atmosphere could warm the planet.

This work built on the research of other 19th-century scientists, such as Joseph Fourier (1768-1830), who hypothesized that Earth would be far cooler without an atmosphere, and John Tyndall (1820-1893) and Eunice Newton Foote (1819-1888), who separately demonstrated that carbon dioxide and water vapor trapped heat and suggested that an atmosphere could do the same, JSTOR Daily reported.

Arrhenius' climate change predictions were largely spot on. Human activities release carbon dioxide, methane and other greenhouse gases that trap radiation from the sun and hold them in the atmosphere to increase temperature like a warming greenhouse, hence the term "greenhouse effect." However, Arrhenius' work was not widely read or accepted at the time, nor was it even intended to serve as a warning to humanity; it can be viewed as such only in hindsight. At the time, his work simply recognized the possibility of humans influencing the global climate and for a long time, people viewed warming as beneficial, according to Weart.

There was some coverage of fossil fuels affecting climate in the general media, according to a now-viral 1912 article first published in the magazine Popular Mechanics, USA Today reported. The article, which ran in a few newspapers in New Zealand and Australia later that year, recognized burning coal and releasing carbon dioxide could increase Earth's temperature, noting that "the effect may be considerable in a few centuries."

The scientific opinion on climate change wouldn't begin to shift until two significant experiments some 60 years after Arrhenius' realization. The first, led by scientist Roger Revelle (1909-1991) in 1957 and published in the journal Tellus, found that the ocean will not absorb all of the carbon dioxide released in humanity's industrial fuel emissions and that carbon dioxide levels in the atmosphere could, therefore, rise significantly. Three years later, Charles Keeling (1928-2005) published a separate study in Tellus that detected an annual rise in carbon dioxide levels in Earth's atmosphere. With carbon dioxide levels known to affect the climate, scientists began to raise concerns about the impact human-related emissions could have on the world.

Musical component.[Spotted at Stolen from Attention to the Unseen].