Freshwater CO2 Emissions Impact on Climate

Our climate is changing, and we need to know why. This work aims to assess potential causes, such as freshwater sources of atmospheric CO2, not previously considered. The rate freshwater bacteria respired dissolved organic carbon, to produce CO2, was measured between 2008 and 2018 globally. A simple in situ chamber incubation method was used to quantify CO2 emissions from aquatic microbial respiration every 15° latitude from the Arctic (66°N) to Australia’s southern point (43°S). Freshwater emits CO2 at a rate seven times higher than fossil fuel combustion, at 242.7 Pg C y−1 compared to 34.6 Pg C y−1, respectively. My study confirmed that fossil fuel burning contributed only 0.3% of this annual increase in atmospheric CO2. Over the same time, the Keeling Curve showed global atmospheric CO2 grew at a rate of 11,500.0 Pg CO2 y−1. The equivalent of 1.15×1013 tonnes would need to be removed annually to have any effect on the rising atmospheric CO2 levels. This quantity is equivalent to eliminating the weight of a million Great Pyramids of Khufu (Egypt) from the atmosphere per year and is beyond our existing capabilities. However, Milankovitch cycles have a predictable influence on our contemporary changing climate. They show, over geological time, that our planet is warming out of an ice age, not because of freshwater and fossil fuel emissions. We do not control our climate fate. We need to forecast climate change impacts to either adapt or move to a more livable environment.