my layman understanding, a real statistician will surely intervene.

standard deviation is a measure that informs about the distribution. A high standard deviation means a "wide bell curve". A low standard deviation means that all values are closely clustered around the middle of the curve.

So if your value is 2 x standard deviation (for example) that means it is a relatively rare outlier, since 2 x standard deviation covers 95% of the bell curve. In particle physics I believe they require 5 standard deviations to confirm an observation.

> Each blue line represents a different year since 1982. The red line is this year. It doesn't just set a new record. It has departed entirely from the range of previous observations.

I'm not an authority on this, but here's is my understanding - I'd appreciate if someone could correct my mistakes.

The baseline of 0.0 represents the average of all years. Anything above / below the baseline is a (standard) deviation from the average. The blue lines are the individual years since 1991 [1] while the red line is the year 2026.

If a line is above the baseline, then the sea-surface temperature was hotter on that day than average. If below, it was cooler than average.

The year 2026 is an outlier, dwarfing all the others starting around June / July. The Nino 3.4 sea-surface temperature is significantly hotter than any previous year during that time. New record, I guess?

[1]: I'm confused about the two date ranges given: 1982-2026 and 1991-2020. I'm assuming this graph is based on measurements from 1982-2026 to calculate the average, but the lines shown are only from 1991-2020, for some statistical reason I don't understand.

You can go to the source website https://climatereanalyzer.org/clim/sst_daily/?dm_id=nino3.4

There's is an interactive chart that's easier to understand

I had the same concerns and think the chart would benefit from color grading the individual years by age. If the other outlier in the opposite direction is equally likely then it should also be concerning (obviously it is not). My understanding is the deviation is from the 1991-2020 subset avg, so a warming trend would be indicated by relative drift towards positive in the std dev across years from 82-present

No. The (standard) deviation is 3.5.

> eat less meat, smaller homes, electric cars, green energy, no flights etc.

How much % of the world's population would have to do those things, for the graph to show a reversal of the trend? 10%? 50%? Everyone?

"Eat less meat, smaller homes, no flights"? Sounds like an average person to me because of poverty, lol. Even my family, well above the threshold for poverty, has to do this.

"Electric cars" is less likely tho because having a car at all is a money drain.