Channeling sounds of stoner and doom metal is “Greenhouse Heat Death”, a microtonal track with growling and guttural vocals over a heavy wah-wah drenched guitar groove, and even some synth work. While its title is a reference to the heat death of the universe (the proposed point at which all energy in the universe has dissipated into heat), the lyrics describe how Earth is warming due to greenhouse gasses emitted into our atmosphere. The song uses food metaphors to explain the situation; Earth is being cooked and fried while humanity is merely “good broth” and “hard yolk.”
A demo of the song was released on Demos Vol. 3: Music To Eat Pond Scum To. This version is made up entirely of electronic instruments with Mellotron and synth bass parts, though its structure is close to what appears on the final version up until its ending. The end of the second solo section is completely different and features a new, strange melody before leading to a long bass outro that fades out. A second demo was released on the ATO repress of Nonagon Infinity. This demo was recorded using a different rhythm and key than the final version. It's also longer than the studio version with a jam coming in around the three minute mark that features muted guitar picking akin to the breaks on “Open Water.” This was most likely recorded in 2016 during the sessions for Flying Microtonal Banana as the track has similarities to other released demos, notably the second demo of “Sleep Drifter.” The Gumboot Soup version was played by Cavs (drums), Cook (guitar), Joey (guitar), Lucas (bass) and Stu (guitar/vocals/synthesizer/percussion) and was recorded by Stu at Rada Studios with additional work done at Flightless HQ. Other additional parts were also recorded at Whammy Bar in Auckland which the band played at from 2017-12-06 to 2017-12-11. It's one of two songs on the album to be mixed by Joey. “Greenhouse Heat Death” initially debuted on Triple R radio on December 19th, 2017 with outlets reporting it as “Greenhouse.” It was released as a single on December 20th alongside “The Last Oasis” and sequenced as the second song on Gumboot Soup on December 31st.
The earliest known performance of “Greenhouse Heat Death” was on 2018-02-18 at the Croxton Park Hotel in Naarm (Melbourne). At the start of the year it was typically played as the second song of the first set behind “Rattlesnake”, but by May the song had been pushed further back in the show. Its last two appearances on 2018-06-11 and 2018-06-16 saw it return back to the beginning of the gig. Since then “Greenhouse Heat Death” has not been played live.