Will need to see more evidence re; smoke/volcano. Spencer is missing the two obvious factors for UAH warmth: GHG and improved satellites with no diurnal drift. Evidence for the last point is the UAH trace - the period after the 2016 nino is much warmer relative to the super nino peak than the period after the 1998 nino. What happened in 1998? the MSU to AMSU transition. Scientists still don't know which satellite was right NOAA-14 or NOAA-15. UAH picked the colder satellite, of course, which looks like the wrong choice when compared against other series. Meanwhile per the article below, recent satellites have essentially no diurnal drift, with very stable performance for climate detection.
https://advances.sciencemag.org/content/4/10/eaau0049.full