For most
lukewarmists it is certain that humans (GHG emissions) are causing the global temperature to increase. But how much? About +0.5C since pre-industrial times.
Everybody also understands there's some natural variation, year-to-year noise which is 20x greater than the human caused warming signal. The trend over the past century is +1.0C / century. Or +0.2C / decade in the second half.
So lukewarmists believe humans are responsible for about half of the observed warming this century (0.5 out of 1.0), the other half is noise which will cancel out in the long run. That implies the projection for future warming is small.
The alarmist position is the opposite: believing that the noise was probably saving us from more warming, and that other mechanisms have acted to keep the observed warming down. In this view, humans are maybe responsible for over a 100% of the warming. This implies that the noise which has kept things manageable will eventually cancel out and we'll see a sharp increase in the rate of warming in the next two decades.
So yes, I think skeptics, lukewarmists, and alarmists are all interested in GMT through 2030 to get a better idea for how much warming we'll get this century.