CO₂ transfer via inland waters

There has been a growing recognition in recent decades that inland waters release considerable amounts of CO₂ into the atmosphere. Until now it has been difficult to obtain global estimates of how much carbon is transferred in this way. This study combines new data sets with a systematic approach to the problem and estimates the global emission rate at about two petagrams of carbon per year from streams, rivers, lakes and reservoirs, which is higher than previous figures because of the contributions from streams and rivers. This new analysis also identifies global hotspots in stream and river evasion, with about 70% of the CO₂ flux occurring over just 20% of the land surface.