5.2 Environmental Evidence

A detailed general introduction to the palaeoenvironment of the Highland Region and its study is offered in Chapter 3, and the National ScARF report provided an overview of the past environment of Neolithic Scotland, together with outstanding research questions and suggestions as to how they may be addressed, so only a summary will be provided here. (See also Section 5.3.1).  

As regards the physical environment, specifically the sea level, the picture is complex. Parts of the coast around the Highland Region have undergone a slight fall in sea level over the past 7000 years, while along the north coast, the sea level appears to have been comparable to today’s level. There will also have been localised variations (Shennan et al 2018), and modern sea level rise relating to climate change is complicating the picture yet further. Essentially, it is unlikely that many, if any, Neolithic sites have been lost to sea level rise in this Region. Inland, the partial inundation of the chamber tombs around Loch Calder (Corcoran 1966), necessitating their excavation in 1961, is wholly due to modern human engineering, not to natural processes.

Regarding vegetation cover, by the early 4th millennium BC when the first evidence for the presence of farming communities appeared in this region, a variegated picture emerged, with pine appearing to dominate the forest cover in central Sutherland and Caithness (Tipping et al 2008). Other tree species dominated elsewhere, and there will also have been tracts of unforested land, and some areas where peat had already begun to form; the complexity of the picture is explored in Chapter 3. As for probable anthropogenic clearance and evidence for cereal cultivation, once again regional and local variation in the timing of both is evident, suggesting variation in the dates when cereals began to be cultivated in different parts of Highland Region. Moreover, the recent re-evaluation and Bayesian analysis for the dating of pollen evidence from Lairg by McDonald et al (2021) has cautioned against a simplistic equation of tree pollen decline with agricultural activity and, conversely, of forest regeneration with cessation of agriculture (see Section 5.4.1.1). Incidentally, the same study does not support cereal cultivation at Lairg as early as c 4200–4000 BC (McCullagh and Tipping 1998, 203).

As regards climate and climate change over the course of the fourth and early third millennia BC, while studies such those carried out by Charman (2010) and Stewart et al (2017) provide a general picture of the main trends, the kind of fine-grained analysis undertaken by Cochrane (2020) for the Late Glacial and Interglacial Transition period (c 15,000–8,000 BC) in Caithness has not yet been attempted for the Neolithic period. Indeed, the chironimid insect evidence that Cochrane used as a proxy for climate change, is less likely to yield useful information during the fourth and third millennia since. As Eileen Tisdall has pointed out (pers comm), the temperature does not vary sufficiently during those millennia to cause the kind of changes in chironimid presence that Cochrane had documented for earlier millennia.

What can be said is that, as with all the other aspects of palaeoenvironment, the palaeoclimate record is complex for the fourth and early third millennia. Stewart et al’s (2017) study of storminess, relating to fluctuations in the position and strength of the polar jet stream and based on the analysis of a core from Shebster, Caithness, concluded that storminess increased to a peak between c 3200 BC and c 2900 BC, then declined over the third millennium. Other climate studies, including Charman (2010), have concluded that from an initial state that was somewhat warmer and drier than during the immediate past, the climate became cooler and wetter over the course of the Neolithic, which will have promoted the rise of the climatically hardier barley to dominate over wheat in Scotland.

The over-riding conclusion to be derived from all the varied palaeoenvironmental work that has been undertaken is that simplistic models are to be avoided, and what is needed is a series of fine-grained local studies that can convey more accurately the variability and trends in the Highland Region.