Chemical Weathering and Erosional Response of Northern New Guinea to Orbital‐Scale Climate Variability

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Plain Language SummaryWe carried out the first research documenting chemical weathering in northern New Guinea for 330 ka. The breakdown of pristine minerals is recognized as being important in regulating atmospheric CO2 and thus controlling the global climate over a variety of timescales. We explore the role played by New Guinea in modulating and responding to climate changes in 330 ka and assess its potential to affect global climate. We reconstruct the changing intensity of chemical weathering and calculate the rates of CO2 consumption and organic carbon burial using well‐established methods. CO2 was consumed in New Guinea more quickly during glacial times because erosion during these periods is more focused on rocks that are more mafic and thus more CO2 consuming. This results in a positive feedback, removing more atmospheric CO2 and allowing the Earth to cool further. The reverse occurs during interglacial times. Organic carbon burial does not vary with climatic cycles and accounts for only ∼15%–20% of the total CO2 drawdown. Modern river sediment loads indicate that New Guinea is much more effective than the major river systems of Asia in removing CO2 from the atmosphere.