Figure 3 shows the results of simulations using the semi-empirical one-dimensional atmospheric-ocean biosphere model (1DAOBM) version 2 (Ollila, 2016), which maintains the GH emission rate at 50 GtCO2 from 2030 on. The results show that in 2100, atmospheric CO2 concentrations will increase to 688 ppm and continue to climb to 935 ppm in 2300. The graph based on the empirical link shows a decrease in CO2 concentration. The reason for this difference is that 1DAOBM-2 takes into account the gradual saturation of the ocean surface layer, which means that the ocean`s ability to absorb CO2 decreases. Finally, the objective is to achieve a new balance between atmospheric CO2 and CO2 in the ocean. For the agreement to enter into force, at least 55 countries, representing at least 55% of global emissions, had to join it. The agreement was opened in April 2016 and was concluded in April 2017. After the head of a country decided to join the agreement, the approval of the national government or the adoption of a national law was required for that nation to participate officially. COP21 does not define the scientific basis of the agreement for the warming effects of anthropogenic emissions. but it relates to a scenario. The IPCC publication “Summary for Policymakers: Mitigation of Climate Change” contributes to the objectives of the UNFCCC and has defined this scenario.
The exact specification of the IPCC (IPCC, 2014) is as follows: according to the simulations of Ollila (2016) by the 1DAOBM-2 model, the residence time of anthropogenic CO2 is 16 years and the same of total CO2 is 55 years. The length of stay of 55 years gives a relaxation period (i.e. the final value of the change) of 4 × 55 years = 220 years, which is significantly shorter than that of the IPCC. The simulations show that while the CO2 emission rate could be maintained at the level of 40 GtCO2 y-1 from 2030, the atmospheric concentration of CO2 would continue to increase at the current rate. However, under the construction scenario, the concentration of 580 ppm in 2100 is much lower than the initial baseline. In 2100, baseline scenarios without further reduction lead to an increase in global average surface temperature of 3.7°C to 4.8°C compared to pre-industrial level (area based on average climate response, from 2.5°C to 7.8°C, taking into account climate uncertainty). The wide variety of these emissions is largely due to differences in emissions of non-CO2 greenhouse gases, such as methane and broussin gas, which vary between two and three models by 2100. Some models with higher non-CO2 emissions have a carbon budget remaining below zero, so more CO2 needs to be removed from the atmosphere than is added by the end of the century. . . .