Lower CO2 consumption from chemical weathering during warmer climates in North New Guinea

New Guinea represents an important potential influence over the consumption of atmospheric CO₂ and global climate because of its large size, rapid erosion and strongly mafic composition. A new sediment record documenting erosion in northern New Guinea since 350 ka shows that stronger rain during interglacial times erodes more accreted continental crust than mafic arc crust. Although sediment is altered more during interglacials, this change in provenance results in a greater impact on the amount of CO₂ consumed per unit weight. Thus silicate weathering is less efficient at removing CO₂ when global climate is warmer, leaving more greenhouse gas in the atmosphere. New Guinea’s climatically modulated erosion thus acts as an amplifier of global climate variations on orbital timescales.