It's a story that appeared in U.S. newspapers in February 1874. The premise was that scientists had discovered the earth was getting hotter and hotter. Europe was predicted to be tropical in 12 years, and soon after that the planet would become too hot to support life. The cause of this warming wasn't carbon emissions, but rather the recent laying of transatlantic telegraph cables, which were supposedly acting like giant electromagnets, pulling the earth into the sun.
This was a very minor nineteenth-century hoax. It didn't generate much interest at the time because it was pretty far-fetched. But it's more interesting to us today because of its depiction of man-made global warming. In fact, I suspect it may be the earliest fictional portrayal of global warming caused by man's technology. At least, I can't find any earlier examples.
The full article about the hoax is in the hoax archive. I've redirected comments there to avoid having duplicate threads.