Abstract Anthropogenic emissions of greenhouse gases (GHGs) are the main cause of Arctic climate change. While carbon dioxide (CO2 ${text{CO} }{2}$) is undoubtedly the largest contributor, the impact of non‐CO2 ${text{CO} }{2}$ GHGs on the Arctic system has not been quantified to date. Here we perform and analyze a new set of climate model experiments designed for this purpose. Focusing on the period 1955–2015, we show that the five important non‐CO2 ${text{CO} }{2}$ GHGs have warmed the Arctic by 0.72–1.11 K, and melted 0.90–1.21 million km2 ${text{km} }^{2}$ of September sea ice. These values amount to 60%–90% of the impacts from CO2 ${text{CO} }{2}$ alone. Individual forcing experiments reveal that ozone‐depleting substances have caused the strongest non‐CO2 ${text{CO} }{2}$ impact, followed by tropospheric ozone and methane, with smaller roles for nitrous oxide and stratospheric ozone. Our findings suggest an alternative pathway to mitigate Arctic climate change, whose effectiveness may depend on whether non‐CO2 ${text{CO} }{2}$ emissions are abated separately from each other or concomitantly.