The phrase "temperature tendency" refers to the general direction or pattern in which the temperature is changing over a certain period of time. It indicates whether the temperature is increasing, decreasing, or remaining stable. Full definition
However, we can measure the temperature and estimate how it changes as a result of air flowing over an area, and then calculate the «leftover» residual temperature tendency to get an idea of how diabatic processes (i.e. convection and radiation) are heating the atmosphere. (hannahlab.org)
With such emissions and temperature tendency, other trace greenhouse gases including methane and nitrous oxide would be expected to increase, adding to the effect of CO2. (journals.plos.org)
Unfortunately we can not just go out and directly measure the temperature tendency from convection. (hannahlab.org)