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<p>Biogenic volatile organic compounds (BVOCs) are important precursors to ozone and secondary organic aerosols in the atmosphere, affecting air quality, clouds, and climate. However, the trend in BVOC emissions and driving factors for the emission changes in different geographic regions over the past 2 decades has remained unclear. Here, regional to global changes in BVOC emissions during 2001–2020 are simulated using the latest Model of Emission of Gases and Aerosols from Nature (MEGANv3.2) with the input of time-varying satellite-retrieved vegetation and reanalysis meteorology data. Comparison of model simulations with the site observations shows that the model can reasonably reproduce the magnitude of isoprene and monoterpene emission fluxes. The spatial distribution of the modeled isoprene emissions is generally comparable to the satellite retrievals. The estimated annual average global BVOC emissions are 835.4 Tg yr<span class="inline-formula">⁻¹</span> with the emissions from isoprene, monoterpenes, sesquiterpenes, and other BVOC comprised of 347.7, 184.8, 23.3, and 279.6 Tg yr<span class="inline-formula">⁻¹</span>, respectively. We find that the decrease in global isoprene emissions (<span class="inline-formula">−0.07</span> % per year) caused by the increase in CO<span class="inline-formula">₂</span> concentrations (<span class="inline-formula">−0.20</span> % per year) is stronger than that caused by changes in vegetation (<span class="inline-formula">−0.03</span> % per year) and meteorological factors (<span class="inline-formula">0.15</span> % per year). However, regional disparities are large. Isoprene emissions increase significantly in Europe, East Asia, and South Asia (0.37 % per year–0.66 % per year). Half of the increasing trend is contributed by increased leaf area index (LAI) (maximum over 0.02 m<span class="inline-formula">²</span> m<span class="inline-formula">⁻²</span> yr<span class="inline-formula">⁻¹)</span> and tree cover. Changes in meteorological factors contribute to another half, with elevated temperature dominating in Europe and increased soil moisture dominating in East and South Asia. In contrast, in South America and Southeast Asia, shifts in vegetation type associated with the BVOC emission capacity, which partly results from the deforestation and agricultural expansion, decrease the BVOC emission and offset nearly half of the emission increase caused by changes in meteorological factors. Overall, isoprene emission increases by 0.35 % per year and 0.25 % per year in South America and Southeast Asia, respectively. In Central Africa, a decrease in temperature dominates the negative emission trend (<span class="inline-formula">−0.74</span> % per year). Global monoterpene emissions show a significantly increasing trend (0.34 % per year, 0.6 Tg yr<span class="inline-formula">⁻¹)</span> compared to that of isoprene (<span class="inline-formula">−0.07</span> % per year, <span class="inline-formula">−0.2</span> Tg yr<span class="inline-formula">⁻¹)</span>, especially in strong greening hotspots. This is mainly because the monoterpene emissions are more sensitive to changes in LAI and are not subject to the inhibition effect of CO<span class="inline-formula">₂</span>. The findings highlight the important roles of vegetation cover and biomass, temperature, and soil moisture in modulating the temporal variations of global BVOC emissions in the past 2 decades.</p>