It means the difference to the average of a certain time frame. Whether it was caused by human activity is a different question. That is why I call it misleading. They certainly want to imply humans caused it, but at the point where they show the chart they haven't really shown it. That requires considering other aspects.
The fastest shifts occurred after large volcanic activity. And cold summers for a few years then led to crop failures.
Am really interested in more analysis of correlation of reduced sunspot activity and then increased volcanic activity. It appears to be a fascinating correlation.
Update - The mammoths with undigested grass in their stomachs, which froze to death while eating, may indicate magnetic pole flip creates faster climate change than volcanic activity.
> Am really interested in more analysis of correlation of reduced sunspot activity and then increased volcanic activity. It appears to be a fascinating correlation.
Sad to see the sunspot conspiracies still alive and kicking. Here, have some 14 year old news about how they don't matter enough to bother with in discussions about today's climate: https://www.nature.com/articles/nature05072
It means the difference to the average of a certain time frame. Whether it was caused by human activity is a different question. That is why I call it misleading. They certainly want to imply humans caused it, but at the point where they show the chart they haven't really shown it. That requires considering other aspects.