Kyle Harper

They don't think of it in terms of a biological event or climatic event.

And since that's come up and you've invited, I'll say a little bit about that.

But this is one of the other –

really exciting frontiers where we're learning new things about the human past that we just didn't know 10 or 15 years ago, that in this case, we now have really, really cool paleoclimate data that helps us understand that this period of the 6th and 7th century was also a period of really abrupt and significant natural climate change.

And so we're all familiar with like anthropogenic climate change, the carbon emissions stay in the atmosphere, trap heat, humans are changing the climate.

It's a big problem.

We can talk about it if you want.

I just like to clarify that like that view is not incompatible with the reality that the climate does also change for natural reasons on every timescale from like really long geological timescales to much shorter timescales.

So we live in the Holocene.

The last 11,700 years have been pretty –

It's stable, pretty warm.

It's an interglacial.

We're literally between ice ages right now.

It's been really stable in the big picture.

Yet, even within that stability, there are smaller scale climate variations and climate changes.

Because we need to understand how the Earth system works, how the climate system works in order to be able to model what's happening.

We need an empirical record of what the climate has done.

So for historians, this is like great news because now we have a huge number of sometimes even pretty high resolution climate reconstructions for historical periods across the Holocene.

And so we now know – like we did not know this 20 years ago when I started graduate school, say, that –

The Roman period experienced some really abrupt episodes of climate change.