How much can El Niño be blamed for the jump in CO2?

Something unusual happened in April this year. Between March and April there was a record month to month jump in atmospheric CO2 recorded at Mauna Loa. It went up by 2.71 ppmv. That's 0.6 ppmv higher than the previous highest month to month jump (2.11 ppmv) back in April 2004. However it's not wise to focus on month to month variations. For example, March could have been lower than expected, which would make the jump seem larger than it should be. (It wasn't.) This article explores some of what causes atmospheric CO2 to go up and down. It's not the answer to everything, however I learnt a lot doing the research and I have some unanswered questions too (like a quantitative answer to the title of this article). (Let me know if you see any mistakes I may have made.)

The chart below shows the month by month increase in atmospheric CO2 since the late 1950s. Hover over the chart for the values. The most recent is April at 407.57 ppmv.

Figure 1 | Monthly CO2 at Mauna Loa. Data source: SCRIPPS CO2 Program