How Long Have We Known About Anthropogenic Climate Change?

At least according to the Rodney and Otamatea Times, Waitemata and Kaipara Gazette



And also the 2012 Popular Mechanics

According to Snopes, well over 100 years: 

On 11 October 2016, the Facebook page “Sustainable Business Network NZ” posted a photograph of a clipping from the 14 August 1912 edition of the Rodney and Otamatea Times, Waitemata and Kaipara Gazette that included a brief item headlined “Coal Consumption Affecting Climate”:

The furnaces of the world are now burning about 2,000,000,000 tons of coal a year. When this is burned, uniting with oxygen, it adds about 7,000,000,000 tons of carbon dioxide to the atmosphere yearly. This tends to make the air a more effective blanket for the earth and to raise its temperature. The effect may be considerable in a few centuries.

This article’s authenticity is supported by the fact it can be found in the digital archives of the National Library of New Zealand.

Further attesting to its authenticity (and perhaps its role as a bit of stock news used to fill space) is that an identical story had appeared in an Australian newspaper a month prior, in the 17 July 1912, issue of The Braidwood Dispatch and Mining Journal, as found in the digital archives of the National Library of Australia.

An even deeper dive reveals that the text of this news item has its origins in the March 1912 issue of Popular Mechanics, where it appeared as a caption in an article titled “Remarkable Weather of 1911: The Effect of the Combustion of Coal on the Climate — What Scientists Predict for the Future”

The science behind this goes back at least 20 years before that.

I first heard about this in 1980.