@chrisnelder To be precise, it is SSP2 basis that took hits recently. It corresponds to a respect of countries' pledges on GHG emissions, and in the recent years we got Trump election and USA out of Paris agreement, the Russian war on Ukraine, and now US and Israël's attack on Iran. These are quite significant events not going in the direction hypothetized by SSP2 ; meanwhile, plane transportation is at its highest.
If we regard SSP2-4.5 emissions, it does seems that up to ~2023 (little more recent data is available), we match that quite well (e.g. https://journals.sagepub.com/doi/10.1177/29768659241304854 figure 3), but the political and economic direction is concerning.