Fig. 1: Decadal variations of emissions, aerosol index and cloud droplet number concentration during 2001–2020 over major industrial regions and their adjacent oceans.

a–d, Anthropogenic SO₂, BC and OC emissions from the Community Emissions Data System (CEDSv_2021_04_21;⁴⁴) over EU (a), NA (b), IN (c) and EC (d). e–h, AI and N_d from MODIS, N_d from CMIP6 hist/ssp245-GHG and hist/ssp245-NAT experiments over EU (e), NA (f), IN (g) and EC (h). i–l, Same as e–h but for adjacent oceans: EUO (i), NAO (j), INO (k) and ECO (l). Here the variables are normalized against the 20-year mean value in each region, meaning the percent deviation from the mean value (in units of %). The time series are smoothed using robust locally weighted regression algorithm (LOWESS) with a seven-year time window. The numbers in the top right corner of each plot show relative trends (% per year). The corresponding multi-year means and absolute linear trends are displayed in Supplementary Table 1. Also shown is the N_d sensitivity (S_AI) calculated from decadal variations of AI and N_d excluding any high-frequency noises.