As we’ve arrived to the end of Game of Thrones Season 7, that’s left us all at the edge of our seats hoping the next year, or two, fly by quickly. In Season 7 Episode 6: Beyond the Wall, we see Daenerys and her dragons fly into battle. Unfortunately, one of her three children was speared by the Night King. While all three dragons kill thousands of wights with their fiery breaths, the GoT mad team at Carbon Consulting Company (CCC) started to think about the amount of carbon emissions released during this epic battle. So, we decided to estimate the carbon emissions from all the fire breathing done by the dragons during the epic battle.
Dragons are massive reptiles that can fly and breath fire as a means of defense— they can even cook food!  It is said that the fire released by dragons is a mixture of chemicals similar to those in ‘gas flaring’. Flare gas (known as “associated petroleum gas”) is a form of natural gas, comprised of 81% Methane, 5% Ethane, 6% Propane, 4% Butane, 1% Nitrogen, and trace amounts of other chemicals. 
Our research unearthed the seminal study of the phenomenon; a report titled ‘From Smaug to Smog: Historical carbon emissions due to dragons in Middle Earth’, a descriptive outline of Drogon’s carbon emissions in the film adaptation of J. R. R. Tolkien novel, The Hobbit. Using this rich source material, the CCC team drew up a broad estimate of Drogon’s carbon footprint in the on-screen battle with the White Walkers in Beyond the Wall. (As we don’t really know the real-time length of the battle or even the dragons’ flight during this time, we are limiting ourselves to the on-screen fire breathing only)
We have determined Drogon’s length to be 70m (referenced by the size of a 747 jumbo) with an estimated weight to be 653.33 tonnes (larger than the recorded weight for Smaug). Assuming flame temperatures of Drogon and Smaug are the same (and yes we know that this is an assumption that transcends vastly different universes and realities), the maximum sustainable energy expenditure is estimated to be 27.65 GJ/day. The maximum emissions are 1.67 kg CH4 per day and maximum emissions are 0.13 kg CH4 per hour. Drogon’s fire breathing time in the fight scene lasted roughly 33 seconds (on-screen), making his total emissions for the battle to 0.073 kg CH4.
On the other spectrum, Rhaegal and Viserion jointly produced maximum emissions of 0.12 kg CH4 per hour, assuming they are both 90% of Drogon’s size. Their combined on-screen fire breathing lasted 66 seconds for a total of 0.13 kg CH4 for the battle scene (assuming all three breathed fire for roughly the same amount of time).
So, what is the carbon footprint of Drogon’s big battle? 1.83 kg CO2e (roughly one-fifteen thousandth of the emissions caused by launching a space shuttle into orbit).
His little brothers, Rhaegal and Viserion, had a total of 3.29 kg CO2e of emissions for the same period.
Given that the population of dragons are minimal in Westeros, as well as Viserion’s death, climate change impacts of the remaining 2 dragons would be negligible (also Winter is here, so maybe a little global warming in Westeros could help!).
But could the resurrection of the ice dragon zombie lead to a new era for the dragons? Only a few more years to find out.