As the sibling comment points out, the rate of increase is important.

Dynamical systems are often sensitive to the value of a parameter, its rate of change and/or its rate of rate of change.

Eg. You can warm milk to a certain temperature (the parameter) on a stove on gentle heat and it will be fine. If you warm it to the same temperature on high heat (i.e. increased rate of parameter), it will burn. That's because the convection process in this system has limited maximum speed.

If you look at when previously the Earth's atmosphere had high CO2, it took hundreds of thousands to many millions of years get there. We did it in a 100 years, so at least a thousand times faster.

I can warm water up slowly or quickly and get the same result. So maybe the substance you're heating plays a role here?

I'm not denying that the rate is significant in this specific conversation, but maybe that wasn't the best example?

Seeing as we're being pedantic, if you heated water slowly enough it would all evaporate before it boiled, so it wouldn't be exactly the same.

The primary difference between a caress of the cheek and a slap to the face is simply the rate at which it occurs.

The Earth has warmed and cooled even more rapidly before. And again I am not disputing the current cause of warning. I am just annoyed with the ignorance of history.

Citations please?

From a cursory look, any such events look like they were part of mass extinctions. I'm curious what exact data you are looking at so I may better understand your statement.

I'm just annoyed with the lack of reading comprehension. My statement was "we've drastically increased one of the primary greenhouse gas concentrations at a rate unseen in Earth's history". I am aware of no other scientific evidence, or even hypotheses, where greenhouse gas concentrations changed as quickly, and that includes periods of extreme vulcanism, such as when the Siberian Traps were created.

Again, if you have any evidence or citations to the contrary, "put up or shut up".

You missed the word 'rate'.

Thank you - that was indeed my primary point. Was a good article yesterday about the "Anthropocene", https://news.ycombinator.com/item?id=40079014, where if you look at graphs of things like temperature, CO2 concentrations, methane concentrations, etc., that the last hundred or so years just basically show a vertical line.

I did not. The Earth has warmed and cooled even more rapidly before.

If you have a source or are referring to something specific, please enlighten us.