Maybe the only good thing about covid hysteria is that it has, for a while, drowned out global warming hysteria. Still, many people have the impression that global temperatures have warmed alarmingly in recent decades. Unfortunately, there is no reliable record of surface temperatures for a number of reasons, including the fact that the activists who are in charge of the records keep changing them to promote the alarmist position.
But that is all right, since warming due to carbon dioxide doesn’t occur at the surface, it occurs in the atmosphere. The only reliable, unfudged record we have of global temperatures is the satellite record in the lower troposphere, which only goes back to 1979. This is the global temperature trend from then until now:
This means that “[t]he linear warming trend since January, 1979 remains at +0.14 C/decade (+0.12 C/decade over the global-averaged oceans, and +0.18 C/decade over global-averaged land).” In other words, at the warming rate that has prevailed since 1979–assuming it continues–the Earth’s average temperature would rise by one degree in 70 years.
How much of that is due to human activity, as opposed to natural variation (e.g., rebounding to normal temperatures after the Little Ice Age), no one knows.
