The rapid warming of the Arctic, perhaps the most striking evidence of climate change, is believed to have arisen from increases in atmospheric concentrations of GHGs¹ since the Industrial Revolution. While the dominant role of carbon dioxide is undisputed, another important set of anthropogenic GHGs was also being emitted over the second half of the twentieth century: ozone-depleting² substances (ODS). These compounds, in addition to causing the ozone hole over Antarctica, have long been recognized³ as powerful GHGs. However, their contribution to Arctic warming has not been quantified. We do so here by analysing ensembles of climate model integrations specifically designed for this purpose, spanning the period 1955–2005 when atmospheric concentrations of ODS increased rapidly. We show that, when ODS are kept fixed, forced Arctic surface warming and forced sea-ice loss are only half as large as when ODS are allowed to increase. We also demonstrate that the large impact of ODS on the Arctic occurs primarily via direct radiative warming, not via ozone depletion. Our findings reveal a substantial contribution of ODS to recent Arctic warming, and highlight the importance of the Montreal Protocol as a major climate change-mitigation treaty.

北极的迅速变暖，也许是气候变化最显着的证据，据信是由于工业革命以来大气中温室气体浓度的增加^{1引起的。}虽然二氧化碳的主导作用是无可争议的，但在 20 世纪下半叶，另一组重要的人为温室气体也在排放：消耗臭氧层的²物质 (ODS)。这些化合物除了会导致南极洲上空的臭氧空洞外，长期以来一直被认为是³作为强大的温室气体。然而，它们对北极变暖的贡献尚未量化。我们在这里通过分析专门为此目的设计的气候模型集成集合来做到这一点，跨越 1955 年至 2005 年期间，大气 ODS 浓度迅速增加。我们表明，当消耗臭氧层物质保持固定时，北极表面的强制变暖和海冰的强制损失仅是允许消耗臭氧层物质增加时的一半。我们还证明，消耗臭氧层物质对北极的巨大影响主要通过直接辐射变暖发生，而不是通过臭氧消耗发生。我们的研究结果揭示了消耗臭氧层物质对最近北极变暖的重大贡献，并强调了《蒙特利尔议定书》作为一项主要的气候变化缓解条约的重要性。