To answer the question of whether the additionally emitted CO2 in the atmosphere is indeed a greenhouse gas, it would be necessary, among other things, to conduct additional research for a radiation source with a temperature similar to Earth's surface temperature and measure the absorption of thermal radiation in a mixture of CO2 and air at different temperatures and pressures, as is the case in Earth's atmosphere at various altitudes.
This is an appeal for money. Their paper is finished; they want more cash to do more research. This is a very common way to end research papers.
