Projects per year
 The sulphur released by the 1815 Tambora volcanic eruption resulted in a net cooling after the eruption. The cold climate was responsible for crop failures, leading to serious famine and high food prices in Europe and North America. The year 1816 became known as the “year without summer”. We performed a series of climate simulations with the UK Met Office model HadGEM2-ES to assess the climate and carbon cycle consequences of the eruption. The model shows a temperature decrease of 1 ± 0.1°C and global precipitation decrease of 3.7% in 1816. The following net primary productivity (NPP) increase is caused by strongly reduced plant respiration and supports the overall increase in land carbon storage after the eruption. Most of the carbon is taken up by the soil reservoir, mainly due to increased litter influx. Overall, the change of combined land and ocean carbon implies an atmospheric CO2 decrease of over 6 ppmv. C3 and C4 grasses, used here as an analogy for crops, revealed globally increasing productivity for C3 grasses/crops (e.g., wheat) by ≥8%, while C4 grasses/crops (e.g., maize) decreased by over 12%. Regional positive C3 and negative C4 NPP are mainly found in the tropics and midlatitudes, whereas positive C4 NPP areas are distributed in marginal areas. Negative C3 grasses anomalies are found in high-elevation and high-latitude regions. These findings highlight the importance of including process-based vegetation or crop model components to represent the potentially nonlinear dependencies on climatic changes.