|Tomorrow belongs to the snowman!|
Invaders From The Ice World (Strange Adventures vol.1 No.79, April 1957) is almost certainly the most unintentionally prescient cautionary tale in the entire history of assorted Silver Age science fiction titles, dealing as it does with dramatic and catastrophic changes to Earth's environment definitely caused by mankind and resulting in extinction-level climate change. Oh, the wacky fun of the Silver Age.
|Ugh, interplanetary snowbirds.|
Using their advanced Plutonian science, the energy-beings drop the regional temperature sufficiently so as to create a sort of cold-based hyperbaric chamber with which to acclimate themselves to Earth's relative heat. Pesky kids take advantage of the Summertime blizzard to craft snowmen which the two invading aliens determine are perfect "snow-suits" capable of maintaining the low temperatures they crave - and which moms love!
The next stage of their plan involves walking around slowly and murdering plant life with the raybeams from their eyes. The ultimate goal, as they explain to a passel of militarymen and concerned scientists, is to eliminate all sources of oxygen-production on Earth, thereby promoting the production of carbon dioxide and making the world not only uninhabitable to native life, but blanketed in a heat-reflecting shield of CO2 with which they'll freeze the planet.
|"WHY we built it, I dunno, but now we got it so let's use it."|
Arguably, the threat of two planet-purloining Plutonians should be an easy fix with an open barbecue, a hairdryer or waiting for them to get to Texas. It turns out, against common sense, that the super-cold snowmen shells can withstand bullets, flamethrowers, grenades, bazookas and atomic blasts. Hope they cleared those kids out before they tested it.
Ultimately, the humans decide to fight fire with fire, as it were, and use an experimental cold beam to turn the snowmen bodies as brittle as glass. This causes the Plutonians to leave in defeat or, conversely, perhaps they read a scientific journal and realized they really just needed to wait a century or so until Earth is rendered devoid of life anyway. Or maybe they went to Neptune, that's what I would have done - the commute alone is so much easier.