Abstract Emissions from agricultural activities constitute 11% of global greenhouse gas emissions and are hard to abate. Here, we present and analyze a consistent empirical assessment of global emissions from agricultural activities from 1910–2015. Agricultural emissions increased 3.5-fold from 1910–2015, from 1.9 to 6.7 GtCO₂eq yr⁻¹. CH₄ emissions, emissions from enteric fermentation and from livestock products contributed the highest fractions of emissions by gases, processes, and products, respectively. A decomposition analysis quantifies the contribution of major drivers of agricultural emissions dynamics. It reveals that globally and across the entire period, changes in population, agricultural production per capita (‘output’), regional distribution of production (‘regional mix’), and composition of final products (‘product mix’, i.e. a shift towards livestock production) all contributed to increasing agricultural emissions. Conversely, declining emissions per unit of production (‘emissions intensity’), particularly for livestock, partly counterbalanced the emissions increase. Significant variations prevail across regions and time periods. Most notably, the composition of final products counteracted agricultural emissions increase from 1910–1950, but growing livestock production has become an increasingly important driver of emissions growth in more recent periods. This finding unravels that increases in livestock production offset the improvements in emissions intensity of industrial agricultural intensification. Our findings underscore the large potential of reducing livestock production and consumption for mitigating the climate impacts of agriculture.