# Evaluating the Effectiveness of Natural Carbon Sinks Through a Temperature-Dependent Model
## 4 Conclusions  
The continuity equation, together with the observed consistent decrease in the \({}^{14}\)C concentration in the atmosphere after 1963 and the observation of temperature-dependent natural emissions, are powerful tools for evaluating observations. One purpose of this article is to explain the recent rise in concentration growth as a consequence of rising sea surface temperatures instead of a hypothetical unobserved decline in absorption by oceans or plants. While the rise in concentration growth is real, the cause is not a failure of sinks but a larger rise in temperature beyond the trend that corresponded to CO\({}_{2}\) level rise. It should, therefore, not be off-limits to consider temperature as a \"normal\" cause of CO\({}_{2}\) concentration changes in the public debate, as an influencing factor instead of speculating about the absence of sinks without evidence. This does not exclude a causality in the other direction; the greenhouse effect, the rather large temperature coefficient on natural CO\({}_{2}\) emissions, certainly limits the possible climate sensitivity. Regarding causality, the first climate-relevant test of the temperature-dependent model was made on the VOSTOK ice-core data [10], where there were no anthropogenic emissions and the CO\({}_{2}\) concentration of the last 400,000 years was modeled from preceding temperature data. The temperature-dependent model makes it possible to separate better between the actual anthropogenic origin of CO\({}_{2}\) changes and the natural causes, among which temperature is a very important one. Many people were confused when, in 2020, no effect of the anthropogenic emission reduction could be seen in the concentration growth. When the temperature effect is removed, as is the case in the simple model, then the effect of the lockdown-caused emission reduction can be seen, e.g., the green curve in Figure 12.  
The most important contribution is that it became possible to separate downwelling absorptions from upwelling natural emissions. Through the evaluation of the bomb test \({}^{14}\)C time series and by the Suess effect correction, we have a reliable estimate of the yearly absorption rate as 5% of the CO\({}_{2}\) concentration. Together with the precise CO\({}_{2}\) concentration measurements on Mauna Loa and the accepted measurements of anthropogenic emissions from the International Energy Agency (IEA), the continuity Equation (1) constrains the yearly net natural emissions. Together with the extended model, we also have an understanding of their temperature dependency. Some misunderstandings and misconceptions are challenged by the discussed concepts. * The most obvious is the argument of some climate skeptics that anthropogenic emissions have no effect because they are apparently \"drowned\" in the huge natural carbon cycle. The fact is that anthropogenic emissions are a direct cause of concentration growth. Nature behaves as a strict net sink. This is obvious from Figure 7. Both models ended up with a significant, consistent net sink effect for the last 70 years when reliable data were available. Therefore, anthropogenic emissions must have significantly contributed to the total concentration growth. The extended model can hypothetically switch off the variability of natural emissions by setting the parameter for the temperature to 0. Alternatively, the anthropogenic emissions can be set to an arbitrary constant value so that only the temperature-controlled natural emissions control the CO\({}_{2}\) concentration growth. * Natural emissions by gardens, animals, and even agriculture, in general, are increasingly becoming a political target. As discussed, increasing natural emissions from biota are almost always a secondary consequence of a previous increase in photosynthesis and, therefore, NPP. But they are only a fraction of NPP. Therefore, extreme care has to be taken not to create more harm than good by carbon-related political interference with biota or agriculture.