Enhanced carbonate and silicate weathering accelerates recovery from fossil fuel CO 2 perturbations

Increasing atmospheric CO 2 and surface temperatures should increase carbonate and silicate weathering rates, directly via warming, and indirectly via the CO 2 fertilization effect enhancing plant productivity. Enhanced weathering should in turn increase alkalinity input to the ocean and accelerate long‐term CO 2 uptake. We added silicate and carbonate weathering and carbonate sediments to an existing global carbon cycle and surface temperature model and subjected it to a range of long‐term fossil fuel emissions scenarios, spanning 1100–15,000 GtC in total. Emissions of ≥7350 GtC dissolve all carbonate sediments, and enhanced carbonate and silicate weathering accelerate subsequent CO 2 removal from the atmosphere by up to a factor of 4. For 1100–4000 GtC emissions, enhanced weathering accelerates CO 2 removal by a factor of 1.5–2.5. However, it takes >1 Myr for silicate weathering to stabilize atmospheric CO 2 . If land use tends to suppress vegetation and weathering rates on this timescale, then CO 2 will stabilize above preindustrial levels.