Neglecting sinks for N2O at the earth's surface: does it matter?

The uptake of nitrous oxide (N2O) occurs at the surface of the earth both in terrestrial and aquatic systems. This uptake is usually neglected in N2O budget studies. In this article, we discuss the likeliness of N2O uptake in different systems. These systems include soils as well as groundwater systems, riparian zones and surface waters. We address the possible consequences of ignoring surface sinks for N2O in global budgets as well as in national emission inventories. Our estimated surface sink is relatively small compared to the estimates of the present-day global emissions. Neglecting a possible surface sink of N2O may, therefore, not have major consequences for atmospheric budget studies on the global scale. However, locally, N2O uptake may be considerable. For countries with large areas prone to N2O uptake, neglecting this sink in national budgets may have important consequences.