Published on July 16th, 2018 | by Carolyn Fortuna0
A Scorching Summer In UK Reveals Crop Circles
July 16th, 2018 by Carolyn Fortuna
The UK enjoyed an uncharacteristically sunny and warm spring. There were more sunny hours in May than in any month since current records began in 1929. It was also the warmest May on record, with the average daytime maximum temperature at 17.0C (62.6F). Those extremes have meant havoc for farmers. Pea shortages. Asparagus-lovers, forget it. As the climate gets hotter with new climatological patterns, though, a fascinating phenomenon has surfaced for Welsh farmers — amidst the burnt fields, ancient circles of green have emerged. They’re crop circles, or crop marks, an ancient Phoenix arising and informing a new agricultural generation.
Great Britain as a whole has been facing unprecedented heat, with Wales at the lead recording one of its 5 driest Junes on record — just 22% of its normal rainfall. As fields have dried and browned, new imprints have emerged — shadows, outlines, and wavy imagery in hues of green. These subsurface archaeological features are reminders of the Iron Age, and climatological changes have made these crop marks and their differences in tone or color evident against the surrounding vegetation.
What Causes Crop Circles/ Crop Marks?
The Iron Age, roughly 800 B.C. until 50 A.D., was a time of subsistence settlements, ranging from a reliance on surplus arable production and local rural habitats to associated pastoral activities. Ditches which hugged settlements later filled with topsoil, creating a fertile border that retained water. Today, residual moisture is apparent through more vibrant greens than the surrounding areas, which, in turn, has invited additional resistance to current drought conditions.
These relatively wetter, fertile patches of land have nourished plants, according to research by the Royal Commission on the Ancient and Historical Monuments of Wales (RCAHMW), which has been documenting the rare agricultural landscape. Dr. Toby Driver, Senior Aerial Investigator, said, “I’ve not seen conditions like this since I took over the archaeological flying at the Royal Commission in 1997. So much new archaeology is showing — it is incredible. The urgent work in the air now will lead to months of research in the office in the winter months to map and record all the sites which have been seen and reveal their true significance.”
By their nature, crop marks are visible only seasonally and may not be visible at all except in exceptionally wet or dry years. Although the growth differences may appear small close up, from the air the pattern they make is more visible, as the small changes can be seen as marked differences in tone or color in the context of the normally growing surrounding vegetation.
Droughts can be reveal agricultural features to cropmark hunters, as the differential growth can become apparent in normally hardy species. This latest dry, hot spell has provided an exceptional opportunity to view and catalog the sites — some which were already known — from the air. Differential growth will naturally follow any features buried below. When the sun is low to the horizon, shadows cast by the taller crops can also become visible.
Greenhouse Effects on Agriculture
Even if global warming is kept below +2°C, European agriculture will be significantly impacted. A white paper in the Earth’s Future journal argues that soil degradation may amplify greenhouse gas impacts substantially and thus further hamper crop production.
The Environmental Policy Integrated Climate (EPIC) model is a useful tool to monitor cropping systems. It was developed to estimate soil productivity as affected by erosion. EPIC simulates approximately 80 crops with one crop growth model using unique parameter values for each crop. It predicts effects of management decisions on soil, water, nutrient, and pesticide movements as well as their combined impact on soil loss, water quality, and crop yields for areas with homogeneous soils and management.
Together with regional climate projections from the European branch of the Coordinated Regional Downscaling Experiment, EPIC allows researchers to understand soil degradation and what’s known as “calorie vulnerability” more precisely. Calorie vulnerability occurs due to insufficient compensation for nutrient depletion. If it is not prevented by adaptation measures, calorie vulnerability has the potential to undermine climate benefits that many municipalities are currently undertaking.
Indeed, uncertainties due to future potentials for crop intensification are about 2–50 times higher than climate change impacts.
Climate variability and soil degradation are among the major threats to agriculture, food security, and global crop yields. Crops are sensitive to changes in temperature and precipitation and to rising atmospheric CO2 concentration. Among the changes, temperature increase has the most likely negative impact on crop yields.
“We have had periods of dry weather in the past, where crop marks and parching have exposed archaeology, but this current spell is really exceptional both in extent and longevity and the last time it was to this extent was probably back in the 1970s,” Louise Barker, a senior investigator of archeology at RCAHMW, noted. “Whilst this obviously presents many challenges, one opportunity that arises from this is the discovery of new heritage sites in desiccated grassland and crops which are visible as parch and crop marks.”
The crop marks are a fascinating peek into history. They also provide some insights into ways that farmers and the scientists can work together to understand how crop practices can have multiple benefits for productivity, soil conservation, and regional climate. The conservation of carbon within the soil helps grow healthier crops and prevents carbon dioxide release into the atmosphere, where it contributes to global warming.
Agricultural scientists often visit farms and give presentations at local farm bureaus to help farmers see the broader changes they create. Farmers care about the health of the land beyond their own bottom lines. They are interested to know what is happening locally and why. Crop marks are a reminder that — at least to some degree — regional land-use can help to mitigate climate effects. With such fluctuations in climate and its effects on agriculture, it is certain that economics, policy, and social networks continue to influence agricultural regions.
And, as the global climate continues to change, strategies for improved land management and climate adaption are increasingly vital to managing our own future. Perhaps looking to the past through phenomena like crop marks is one way of understanding our agricultural present.
Photos: Toby Driver (RCAHMW)