Climate in the Iron Age

[The Gypsy]

My question: How different was the climate in the late Roman Iron Age around Europe than it is today?

And additionally what was the impact on the cultures that developed in Europe in the period?

[Brennus]

OOOH! Lovely question. Full response coming soon!

[Brennus]

The climate was not as different as today. During the Late Bronze Age and Iron Age there were two major climate fluctuations. The first of these c.1000/800BC resulted in a cooling of the climate. Along the Atlantic seaboard this had the result of producing a wetter climate which in turn resulted in many of the marginal, upland settements of Britain and Atlantic Gaul being abandoned. It is quite likely a similar thing happened in Ireland, although it is quite difficult to be sure as, following the end of the Bronze Age (c.1000BC Western Europe, c.800 BC Britain, c.600 BC Ireland) the Irish settlement record becomes as scant as a stripper's clothes. Palyonological data from Irish peat bogs does show a regeneration of tree coverage around this time, which has been interpreted as indicating a decline in population and shift to pastoralism as a result of climate change. The same climatic change does not really appear to have impacted on Scandinavia or Western Iberia, and both areas show a great degree of settlement continuity until effects of the Romans become felt much later in those areas.

Around c.300BC there was an improvement in climate and temperatures rose which appears to have resulted in an expansion of agriculture across north western Europe. In Britain we can detect an expansion of field systems in the south, as well increased levels of wheat being cultivated. In Ireland we also see the introduction and subsequent develop of a localised form of the La Tene culture, as well as several major earthwork and structural constructions such as the Black Pig's Dyke and Emain Macha in Ulster, all of which would have required a larger, more centralised population than appears to have existed in the earlier Iron Age. In Northern Gaul there is likewise an intensification of agriculture (although French archaeologists will tell you this is because the Belgae arrived at this time rather than being the result of a warmer climate) whilst in the Netherlands the old grabenfelt cremation culture ends and we see people begin to move to much more permanent settlements with expanded agriculture. A similar process can be detected in Jutland around a century or two later. Likewise in central and southern Gaul, c.200BC, there is a major expansion in the number of farmsteads, which can be explained as being the result of a population expansion based on increased food production which in turn can be linked to a warmer climate.

During the Roman period there does appear to have been a degree of anthropogenic global warming. Roman industry was on a much larger scale than much of the indigenous industry which it replaced in western Europe (although exceptions such as central Gaul exist). For example in Iberia and western Britain huge lead mines were opened up. Recent research has suggested that in excess of 50% of the timber grown in the Roman Empire was used as fuel and Roman sites like Pompeii have found massive amounts of charcoal. Likewise the Romans also developed industrial scale charcoal producing sites (which you need if you have cities like Rome and Capua). All of this contributed to further global warming. By late Antiquity, however, it seems this warming was having similar affects to the climate change we are observing today, with the Gulf Stream being put out of place resulting in a return to a wetter, cooler climate. Around this time (although due to a variety of social reasons also) there was a decline in agricultural output and population decline.

[TiagoJRToledo]

Well, I concur with Brennus' response, to a degree.

There wasn't really a huge difference from today's climate, but I would argue that that isn't necessarily true in places like Northern Africa and Mesopotamia. Evidence points towards the climates of these places being much more temperate and the land more fertile than today's arid predominance. The great productive centres of common ceramics and Terra Sigillata of Northern Africa (those known in Tunisia) are actually located inland, as opposed to near the great populated hubs or water streams, which would indicate perfect living conditions were today you can only pass by.

In Mesopotamia, the same would apply. Accounts report that the climate was much more forgiving than today's, and the land was much more fertile and lush. We have to remember that Mesopotamia owes much of the state it is in today to Genghis Khan ordering the destruction of dams and irrigation systems to transform Mesopotamia into a frontier land.

In regards to Roman industry affecting climate change, I would contest that. I do agree that CO2 levels in the atmosphere only surpassed the Roman levels in the Industrial Revolution of the 19th century, but I would argue that the planet has been moving towards an heating period far before the Romans ever came. We only have to have in mind that in 12000 BC, Egypt and the Sahara were covered in tropical forest, and that same forest disappeared with no interference from Man.

And as the side note, we have to always consider the changes that occurred in the geomorphology when we study a culture or a territory. Just to give some examples: the Tagus estuary (Lisbon, Portugal) was much more wide, and at least 50% of today's Lisbon territory was under water; this same river was navigable up to Madrid until the 17th century, and now you can't even get to Santarém; Cadiz (southern Spain) was settled by Phoenicians not because it now is a peninsula, but because it was an island in the 8th century B.C.
This is why I think many places are not found, or are misinterpreted, because people look to the ground as it is now, and not as it was 2000 years ago.

Hope I was of assistance

[Brennus]

Thank you for filling in the glaring gap I left which is North Africa and the Near East.

When you say the planet had been moving towards a warming period does that just apply to the Roman period or extend until the 19th century?

And as the side note, we have to always consider the changes that occurred in the geomorphology when we study a culture or a territory. Just to give some examples: the Tagus estuary (Lisbon, Portugal) was much more wide, and at least 50% of today's Lisbon territory was under water; this same river was navigable up to Madrid until the 17th century, and now you can't even get to Santarém; Cadiz (southern Spain) was settled by Phoenicians not because it now is a peninsula, but because it was an island in the 8th century B.C.
This is why I think many places are not found, or are misinterpreted, because people look to the ground as it is now, and not as it was 2000 years ago.

Very true. In Northern Europe many areas of the modern coastline were now submerged, such as the Norfolk Fens or the Dutch coast. Interestingly though the coast was larger in some areas, such as Yorkshire.

[TiagoJRToledo]

You are most welcome.

When you say the planet had been moving towards a warming period does that just apply to the Roman period or extend until the 19th century?

It applies to the first and second millennium as a whole, even though periods of cooling existed. We know that between extreme cooling periods (Ice Ages) there are extreme warming periods. The difference is that in this warming period, the human species is mass-connected and they view their actions as damaging. What would we be discussing if we we're in a cooling period?

This is not to say that human action is harmless, but I truly believe that the Planet has taken more damage the last 4,5 billion years than it has taken in the last 200 years, and it is still rotating with life in it. The world will change, whether we like it or not, and this alarmism is just the human race feeling threatened.

[TiagoJRToledo]

My question: How different was the climate in the late Roman Iron Age around Europe than it is today?

And additionally what was the impact on the cultures that developed in Europe in the period?

Uff, this one's a doozy. I'll wait for Brennus' full response, and contribute my part. I would also like to address the issue of geomorphology in ancient times vs today's geomorphology, and what problems arise from this.