Heatwave unveils ancient settlements in Wales | Hacker News Reader

Heatwave unveils ancient settlements in Wales

bbc.co.uk

It is mindboggling to me that ancient humans could have had such an impact that it's still seen today without concrete, stones, or any lasting structure. Just digging a ditch, then forgetting about it for two thousand years, until one day you can see dark lines in the grass.

Absolutely staggering. I wish they knew that they'd have made such a long-lasting impression on the Earth.

From my house, in North Wales, I can see a vast landscape shaped hugely by ancient hands - Snowdonia. The hills were once heavily forested, and held springs and glades in which Mesolithic, Celtic and Roman peoples lived and farmed - but they are now all moorland, as the trees were felled thousands of years ago, for construction and grazing.

Much of what we think of as natural landscape was made by man.

Even that which is patently unnatural passes without much consideration- the neighbouring farm sits smack atop a Roman fort (situated on an inconvenient hilltop between a known fort on the conwy river and a known fort atop a mountain, which has a view to the sea on one side and our hill, but not the river, on the other) - and my garden atop a Roman road - and nobody knows. The dead giveaway was when we took the mouldering plaster (gypsum atop lime) off the internal walls of the house, to find dressed masonry, and one slab with part of a funerary inscription upon it - the cottage was built from spoilage from the road and tombs that lined it - 400 years ago they would have just been some handily squared off chunks of stone, ideal to build with.

I’m not a local or an expert in this area, but do spend a week or two at least once a year in the mountains, either the Lake District or Wales, so have had a few conversations about this in the past.

> ”as the trees were felled thousands of years ago”

Might you have a source on this you could share? I was under the impression that at least the majority of the deforestation happened in recent centuries or even decades, rather than thousands of years.

I did a quick google and didn’t immediately find much detail, although this [0] article from the Independant claims “half of its ancient woodland lost since the 1930s” talking about Britain as a whole.

Maybe it happened much earlier in North Wales?

Anyway, wherever the line is between natural and man-made, I still really love Snowdonia - was there most recently two months ago (staying quite near you as it happens, a few miles inland from Conwy), it’s such a nice place to get away from city life for a little.

There’s a guy who has been campaigning / writing a lot about this subject (I think specifically about the Lake District but might be wrong) pushing for more tree planting, but I can’t think of the name right now... Edit: George Monbiot. I don’t have time right now to revisit his writing but just remember he’s interesting on the topic.

[0] https://www.independent.co.uk/environment/nature/worrying-sl...

It's true about the trees being felled thousands of yours ago; it's believed to be the same in my local countryside, the Peak.

That claim about half of ancient woodland lost since the 1930s : that's true, but it's referring to what ancient woodland still remained in the 1930s compared to what remains now. Both are very small areas, compared to the amount of land which became forested after the last ice age.

A quick reference I've found; wikipedia (https://en.wikipedia.org/wiki/Blanket_bog) has "In some areas of Europe, the spread of blanket bogs is traced to deforestation by prehistoric cultures.", cited to an article in Nature: Moore, P. D. (1973). The influence of prehistoric cultures upon the initiation and spread of blanket bog in upland Wales. Nature, 241, 350–353.

>Much of what we think of as natural landscape was made by man.

We have similar in Ireland, blanket bogs here were essentially man made.

Inuit whaler's leftovers from four centuries ago are still detectable due to elevated nutrient levels in the ponds that were next to where they butchered their take.

http://www.pnas.org/content/pnas/101/6/1613.full.pdf

Genuinely surprised me when I first read about it.

Near to the Scottish village where I grew up there was a cliff sided promontory reaching out into the sea - this had once held a Pictish fort from well over 1000 years ago and you can easily pick out fragments of burned wood from areas of erosion.

Perhaps it was burned down as part of an early Viking raid (there were notable battles against the Vikings in the area) - who knows?

Edit: Stuff like that is one of the reasons I love living in the UK - the hill behind the house where I currently live has a staggering amount of history - from a Roman camp of Agricola, to a dark age fort, to medieval stuff, 19th century industry and 20th century wars. And that's one small fairly unexceptional hill.....

That's what I find so fascinating about living in New Zealand. There are pubs in the Europe that are older than the first human settlements in New Zealand. Sean's Bar in Ireland dates back to 900 CE.

The first people to arrive in New Zealand, the Maori, arrived c. 1300 CE. New Zealand was the last major land mass to be settled by humans apart from Antarctica.

In 700 years, humans managed to destroy 2/3 of New Zealand's forest cover and drive to extinction the largest bird in existence (at the time) and also the largest eagle in existence: https://en.wikipedia.org/wiki/List_of_New_Zealand_animals_ex...

Iron age hill forts and stone age burials can be very prominent features of the landscape. It's not just latent, occasional traces like the ones that have become visible in the last few weeks which survive.

They could build to last in the stone age, and there's no reason to believe that they would be surprised that their monuments are still standing today...

When it comes to the latent evidence of human occupation, I guess it's a bit more unexpected for it to become so visible to us. But even stone age cooking fires leave very permanent traces. https://en.wikipedia.org/wiki/Fulacht_fiadh

Skara Brae on Orkney still has stone furniture from about 5 thousand years ago:

http://www.orkneyjar.com/history/skarabrae/furniture.htm

Now imagine what we will leave! And we know that we are making "such a long-lasting impression on the Earth"

Douglas Adams' idea of an "entire geological layer of compressed shoes" sounds a lot less daft than it used to. (-:

* https://scientificamerican.com/article/humans-leave-a-tellta...

For those interested in aerial archeology I recommend the work of French archeologist Roger Agache, who pioneered the domain in France in the '60s and '70s and based on whose work tens if not hundreds of Roman-era villas have been mapped in the plains located between the Loire valley and the Northern area of Paris. Just a couple of links: http://www.archeologie-aerienne.culture.gouv.fr/en/discip5-p... (presenting his work in English) and especially this http://www2.culture.gouv.fr/public/mistral/memoire_fr?ACTION... (with actual aerial photos taken by Agache and his team).

Something similar is happening in Holland, where it's possible to see where the historical fields were within current field divisions.

https://www.ad.nl/binnenland/nederland-zo-droog-dat-zelfs-hi...

Though thats only from 50 years ago.

What is nice is that the article mentions the rain shortage, which is a nice way to compare.

Not to be pedantic but does it really qualify as a heat wave? Essentially the whole planet (with a few exceptions) is 2-3 F hotter than the last 100 year avg and the 3-4 highest month ever measured. This is really just new normal temperatures in a continuing upward trend.

I’m sure lots of people in the UK would like to believe that a summer like this is the ‘new normal’. But I can attest to the fact that the last time temperatures and rainfall were like this in the UK was in 1995 and before that 1976 (which I don’t quite remember, but I was there)

Oh yes. We rarely get a runway of heat like this for such a length of time.

Plus, even if not technically a heatwave, we'd still call it one as laypeople. We are built to withstand the cold and wet (buildings, wardrobes, etc). It becomes extremely uncomfortable in hot weather no matter how much we like to moan about shite weather.

Yes, because a heatwave is defined as a period of high temperature relative to the normal.

I live in the UK, and the weather over the last six weeks has been exceptionally dry and warm compared to our usual summer weather [1]. It might not be a heatwave in some technical sense, but here on the ground that's how people are describing it.

[1] "Three fine days and a thunderstorm"

We haven't had a hosepipe ban around here yet so it's not a proper heatwave :)

Totally, it's not only heat wave but also lack of rain. Normally it rains every 3-6 days in Wales, last rain longer than 3minutes I remember was in beginning of May. Last weather with these temperatures I remember is form 2011, but lasted only 3 days in September.

" Essentially the whole planet (with a few exceptions) is 2-3 F hotter than the ... 3-4 highest month ever measured. "

Can you elaborate on this?

I wouldn't be able to until later, but it's fairly easy to find the details under the NOAA's site. They have visualizations and methodology, amazing public resource.

I wonder if this explains crop circles in the USA

Interesting thought but crop circles are made by crops being pressed down in to complex patterns, so probably not?

https://www.google.co.uk/search?q=crop+circles&num=100&sourc...

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