Hacker News Reader

Comment by rsecora | Hacker News Reader

For those wondering why there is zig zag in the plot after 1958. The data source changed at that date [1].

  * 1000 - 1958: Historical CO2 record from the Law Dome DE08, DE08-2, and DSS ice cores

  * 1958 - Today: in situ air measurements at Mauna Loa, Observatory, Hawaii.

[1] https://www.co2levels.org/#sources

View on HN

I came to ask exactly this! Although, any clues for why the Hawaii measurements follow that pattern?

It's due to vegetation growth during the summer in the northern hemisphere

https://www.climate.gov/news-features/understanding-climate/....

Oh wow! So interesting to see such a concrete impact from vegetation!

Hawaii does month by month measurement and the seasons have vastly different CO2 levels due to plant activity. Going back further was just a rough yearly average.

The zig zags are a reasonably smooth yearly wave if you zoom into them.

Reply on news.ycombinator.com