[KnightOfWords]

Historical civilisations were very vulnerable to changes in local climate as they were heavily reliant on local food production, whereas we routinely ship food across oceans. Events like the [Little Ice Age](https://en.wikipedia.org/wiki/Little_Ice_Age) barely show up in the global climate record.

Earth's climate has varied greatly over time but its the current rate of change that is so alarming. During the last ice age it was about 4.5 degrees colder but it took 10,000 years to reach modern temperatures. We're currently on a path to changes of that magnitude within the next 70-100 years.

[chrisco255]

You're incorrect about your assumptions. If you click the link in the parent post, you'll see that temperatures swung as much as 8C during the ice age. These events are called Dansgaard-Oeschger events (https://en.wikipedia.org/wiki/Dansgaard%E2%80%93Oeschger_eve...) The warming would happen rapidly (within 3 decades), followed by a stepped down cooling period (often lasting hundreds of years). This happened repeatedly during the most recent glacial.

And then more recently, after the last glacial period had ended, you had incidents like the Younger Dryas, for example, where temps plunged to near ice age levels (up to 6C drop in a few decades) and then rapidly warmed all of a sudden. If you read https://en.wikipedia.org/wiki/Younger_Dryas) some are suggesting that a warming episode at the end of the Younger Dryas occurred in as little as a few years and warmed global temps by 7C.

Note, that by the end of the Younger Dryas, the Arctic was as much as 7C hotter than it is today (https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019...).

There's thousands of papers on the Little Ice Age. It certainly shows up all over the world in the fossil record. https://www.sciencedirect.com/search/advanced?qs=little%20ic...

[GeneralPie]

"But there have been several times in Earth’s past when Earth's temperature jumped rapidly, in much the same way as they are doing today. Those times were caused by large and rapid greenhouse gas emissions, just like humans are causing today. In Earth's past the trigger for these greenhouse gas emissions was often unusually massive volcanic eruptions known as “Large Igneous Provinces,” with knock-on effects that included huge releases of CO2 and methane from organic-rich sediments. But there is no Large Igneous Province operating today, or anytime in the last 16 million years. Today’s volcanoes, in comparison, don’t even come close to emitting the levels of greenhouse gasses that humans do.

Those rapid global warming events were almost always highly destructive for life, causing mass extinctions such as at the end of the Permian, Triassic, or even mid-Cambrian periods. The symptoms from those events (huge and rapid carbon emissions, a big rapid jump in global temperatures, rising sea levels, ocean acidification, widespread oxygen-starved zones in the oceans) are all happening today with human-caused climate change. The outcomes for life on Earth were often dire. The end Permian extinction saw around 90% of species go extinct, and it left tropical regions on the planet lethally hot, too hot for complex life to survive. The Triassic extinction was another, one of the 5 biggest mass extinctions in the geological record. Even in the end Cretaceous extinction, in which dinosaurs were finally wiped out by an asteroid impact, a major global-warming extinction event was already underway causing a major extinction within 150,000 years of the impact. That global warming 66 million years ago was due to catastrophic eruptions in India, which emitted a pulse of CO2 that sent global temperatures soaring by 7°C (13°F).

So yes, the climate has changed before, and in most cases scientists know why. In all cases we see the same association between CO2 levels and global temperatures. And past examples of rapid carbon emissions offer no comfort at all for the likely outcome from today’s climate change."

https://skepticalscience.com/climate-change-little-ice-age-m...

[KnightOfWords]

> ...you'll see that temperatures swung as much as 8C during the ice age. The last glacial period itself covers some 100,000 years.

I could have phrased it better, I'm talking about the temperature difference between the end of the last age and the current day.

> ...Dansgaard-Oeschger events

The recorded temperature swings are local rather than global, global temperature does not rise by five degrees in a matter of decades unless something catastrophic happens.

> There's thousands of papers on the Little Ice Age. It certainly shows up all over the world in the fossil record.

Yes, but average global temperatures were barely affected.

[pjc50]

And what was the effect of that on animal life? Not great: https://en.wikipedia.org/wiki/Quaternary_extinction_event#Pl...

[antocv]

Thats why I hate these Greta style "climate activists", since they only focus on climate, as if thats the only bad shit going on concerning environment. And even so, they are wrong about "apocalypse" style of events.

Even if you solve atmospheric conditions, CO2 and temperature, still you have the pollution of the waters, mass extinctions due to habitat loss, car-tyres rubbering off everywhere, unknown untested toxins even on your cloths. Thats like, not talked about.

EDIT: Cant believe somebody downvoted you. Yes nature has done fast changes, faster than human-induced change currently, and "nature" has mass-exterminated most of its life several times over, and other forms of life caused the deaths and biological disaster for most of other life on earth as well. These are facts.

Somehow these Greata climate activists, would like to believe that humans are more powerful in their destruction than cyanobacteria. Wishful thinking really.

[bregma]

There's a good deal of observation bias at play here.

We currently track the "average annual daily global mean temperature" to somewhere around 4 digits of precision, with an accuracy of around 3 digits of precision (back in the day my university TAs would fail any lab report with inverse precision like that, but I'm no PhD in climate science), and with a time frame of hours. Estimated historic temperatures are presented with 2 or 3 digits of precision over a timeframe of centuries or kiloyears.

Saying current trends are unprecedented is motivational and technically correct, but not scientifically sound given the actual data. Well, science as in hard sciences like chemistry and physics in which we could run controlled experiments to generate confidence in our understanding; not soft sciences like economics or nutrition where controlled experiments would be unethical and results are only as good as the next product you're selling.

My point is that you can see the current short-term trends because we have precision and accuracy to be able to do that. We lack the precision and accuracy of historical data to be able to do that, which makes it an argumentum ad ignorantiam.