This study uses high-resolution sedimentary mercury (Hg) data from the Llanbedr borehole in Wales to estimate carbon emissions from large igneous provinces (LIPs) during the Early Jurassic period (195–175 Ma). The data reveal that periods of elevated Hg levels coincide with significant carbon-cycle changes, including the Toarcian Oceanic Anoxic Event (T-OAE). By analyzing Hg concentrations and accounting for host-phase effects, the researchers estimate that LIP-related carbon emissions, primarily CO₂, were substantial enough to drive environmental changes. However, these emissions are lower than those predicted by some carbon-cycle models, suggesting that additional factors, such as feedback mechanisms or co-emitted gases, may be necessary to fully explain the observed carbon-cycle perturbations. The study highlights the potential of Hg as a proxy for quantifying past carbon emissions and underscores the importance of integrating Hg records with climate models to better understand Earth system responses to large volcanic events. The findings suggest that LIP activity, particularly the Karoo–Ferrar LIP and Central Atlantic Magmatic Province (CAMP), played a significant role in the environmental changes during the Early Jurassic, including the T-OAE and other carbon-isotope excursions. The study also emphasizes the need for more comprehensive models that account for the complex interactions between volcanic emissions, climate feedbacks, and the global carbon cycle.This study uses high-resolution sedimentary mercury (Hg) data from the Llanbedr borehole in Wales to estimate carbon emissions from large igneous provinces (LIPs) during the Early Jurassic period (195–175 Ma). The data reveal that periods of elevated Hg levels coincide with significant carbon-cycle changes, including the Toarcian Oceanic Anoxic Event (T-OAE). By analyzing Hg concentrations and accounting for host-phase effects, the researchers estimate that LIP-related carbon emissions, primarily CO₂, were substantial enough to drive environmental changes. However, these emissions are lower than those predicted by some carbon-cycle models, suggesting that additional factors, such as feedback mechanisms or co-emitted gases, may be necessary to fully explain the observed carbon-cycle perturbations. The study highlights the potential of Hg as a proxy for quantifying past carbon emissions and underscores the importance of integrating Hg records with climate models to better understand Earth system responses to large volcanic events. The findings suggest that LIP activity, particularly the Karoo–Ferrar LIP and Central Atlantic Magmatic Province (CAMP), played a significant role in the environmental changes during the Early Jurassic, including the T-OAE and other carbon-isotope excursions. The study also emphasizes the need for more comprehensive models that account for the complex interactions between volcanic emissions, climate feedbacks, and the global carbon cycle.