Essex Rock

All landscapes are built on rock: from hard stone for building with, to the softest clay or sand. Each piece of rock is a storehouse of prehistorical information; even a simple pebble from the garden has its own complex tale to tell. Geology is the great detective science that can unlock these secrets. In this entertaining and eye-opening book, the authors take a deep dive – quite literally – into their home county of Essex. We are all living in an ice age, an ongoing event that has hugely affected Essex over the last 3 million years. Yet this county was born more than 500 million years ago. Our story begins when the land we know as Essex was part of a large continent close to the South Pole, tracing the geological processes that continue to shape the countryside around us. The form of the land, boulders on village greens, road cuttings, cliffs, stones in church walls – they can all bring geology to light in unexpected and fascinating ways. Aimed at a general readership with no scientific background, chapters progress from fundamentals to intricate details of geological investigations and cutting-edge research. Richly illustrated with photographs and colour diagrams, here the geology of a county is visualised and brought to life as never before, along with pertinent environmental insights in the light of climate change that is happening now.

Glacier response to Holocene warmth inferred from in situ ¹⁰Be and ¹⁴C bedrock analyses in Steingletscher's forefield (central Swiss Alps)

Mid-latitude mountain glaciers are sensitive to local summer temperature changes. Chronologies of past glacier fluctuations based on the investigation of glacial landforms therefore allow for a better understanding of natural climate variability at local scale, which is relevant for the assessment of the ongoing anthropogenic climate warming. In this study, we focus on the Holocene, the current interglacial of the last 11 700 years, which remains a matter of dispute regarding its temperature evolution and underlying driving mechanisms. In particular, the nature and significance of the transition from the early to mid-Holocene and of the Holocene Thermal Maximum (HTM) are still debated. Here, we apply an emerging approach by combining in situ cosmogenic 10Be moraine and 10Be–14C bedrock dating from the same site, the forefield of Steingletscher (European Alps), and reconstruct the glacier's millennial recession and advance periods. The results suggest that, subsequent to the final deglaciation at ∼10 ka, the glacier was similar to or smaller than its 2000 CE extent for ∼7 kyr. At ∼3 ka, Steingletscher advanced to an extent slightly outside the maximum Little Ice Age (LIA) position and until the 19th century experienced sizes that were mainly confined between the LIA and 2000 CE extents. These findings agree with existing Holocene glacier chronologies and proxy records of summer temperatures in the Alps, suggesting that glaciers throughout the region were similar to or even smaller than their 2000 CE extent for most of the early and mid-Holocene. Although glaciers in the Alps are currently far from equilibrium with the accelerating anthropogenic warming, thus hindering a simple comparison of summer temperatures associated with modern and paleo-glacier sizes, our findings imply that the summer temperatures during most of the Holocene, including the HTM, were similar to those at the end of the 20th century. Further investigations are necessary to refine the magnitude of warming and the potential HTM seasonality.

Evidence that modern fires may be unprecedented during the last 3400 years in permafrost zone of central Siberia, Russia

Recent climate change in Siberia is increasing the probability of dangerous forest fires. The development of effective measures to mitigate and prevent fires is impossible without an understanding of long-term fire dynamics. This paper presents the first multi-site palaeo-fire reconstruction based on macroscopic charcoal data from peat and lake sediment cores located in different landscapes across the permafrost area of Central Siberia. The obtained results show similar temporal patterns of charcoal accumulation rates in the cores under study, and near synchronous changes in fire regimes. The paleo-fire record revealed moderate biomass burning between 3.4 and 2.6 ka BP, followed by the period of lower burning occurring from 2.6 to 1.7 ka BP that coincided with regional climate cooling and moistening. Minimal fire activity was also observed during the Little Ice Age (0.7 – 0.25 ka BP). Fire frequencies increased during the interval from 1.7 to 0.7 ka BP and appears to be partly synchronous with climate warming during the Medieval Climate Anomaly. Regional reconstructions of long-term fire history show that recent fires are unprecedented during the late Holocene, with modern high biomass burning lying outside millennial and centennial variability of the last 3400 years.

Pacific multidecadal (50–70 year) variability instigated by volcanic forcing during the Little Ice Age (1250–1850)

The Pacific decadal oscillation (PDO) is the leading mode of decadal climate variability over the North Pacific. However, it remains unknown to what extent external forcings can influence the PDO’s periodicity and magnitude over the past 2000 years. We show that the paleo-assimilation products (LMR) and proxy data suggest a 20–40 year PDO occurred during both the Mediaeval Climate Anomaly (MCA, ~ 750–1150) and Little Ice Age (LIA, ~ 1250–1850) while a salient 50–70 year variance peak emerged during the LIA. These results are reproduced well by the CESM simulations in the all-forcing (AF) and single volcanic forcing (Vol) experiments. We show that the 20–40 year PDO is an intrinsic mode caused by internal variability but the 50–70 year PDO during the LIA is a forced mode primarily shaped by volcanic forcing. The intrinsic mode develops in tandem with tropical ENSO-like anomalies, while the forced mode develops from the western Pacific and unrelated to tropical sea surface temperature anomalies. The volcanism-induced land–sea thermal contrast may trigger anomalous northerlies over the western North Pacific (WNP), leading to reduced northward heat transport and the cooling in the Kuroshio–Oyashio Extension (KOE), generating the forced mode. A 50–70 year Atlantic multidecadal oscillation founded during the LIA under volcanic forcing may also contribute to the forced mode. These findings shed light on the interplay between the internal variability and external forcing and the present and future changes of the PDO.

Three Millennia of Vegetation, Land-Use and Climate Change in SE Sicily

This study presents the first Late Holocene marine pollen record (core ND2) from SE Sicily. It encompasses the last 3000 years and is one of the most detailed records of the south-central Mediterranean region in terms of time resolution. The combined approach of marine palynology and historical ecology, supported by independent palaeoclimate proxies, provides an integrated regional reconstruction of past vegetational dynamics in relation to rapid climatic fluctuations, historical socio-economic processes, and past land-use practices, offering new insights into the vegetation history of SE Sicily. Short-term variations of sparse tree cover in persistently open landscapes reflect rapid hydroclimatic changes and historical land-use practices. Four main phases of forest reduction are found in relation to the 2.8 ka BP event, including the Late Antique Little Ice Age, the Medieval Climate Anomaly, and the Little Ice Age, respectively. Forest recovery is recorded during the Hellenistic and Roman Republican Periods, the Early Middle Ages, and the last century. Agricultural and silvicultural practices, as well as stock-breeding activities, had a primary role in shaping the current vegetational landscape of SE Sicily.

Inventory and classification of the post Little Ice Age glacial lakes in Svalbard

Rapid changes of glacial lakes are among the most visible indicators of global warming in glacierized areas around the world. The general trend is that the area and number of glacial lakes increase significantly in high mountain areas and polar latitudes. However, there is a lack of knowledge about the current state of glacial lakes in the High Arctic. This study aims to address this issue by providing the first glacial lake inventory from Svalbard, with focus on the genesis and evolution of glacial lakes since the end of the Little Ice Age. We use aerial photographs and topographic data from 1936 to 2012 and satellite imagery from 2013 to 2020. The inventory includes the development of 566 glacial lakes (total area of 145.91 km2) that were in direct contact with glaciers in 2008–2012. From the 1990s to the end of the 2000s, the total glacial lake area increased by nearly a factor of six. A decrease in the number of lakes between 2012 and 2020 is related to two main processes: the drainage of 197 lakes and the merger of smaller reservoirs into larger ones. The changes of glacial lakes show how climate change in the High Arctic affect proglacial geomorphology by enhanced formation of glacial lakes, leading to higher risks associated with glacier lake outburst floods in Svalbard.

Documentary Evidence of 17th Century Landcover and Climate Change in Northern China and Mongolia Compared to Modern Spectral Greening Trends

Fighting land degradation of semi-arid and climate-sensitive grasslands are among the most urgent tasks of current eco-political agenda. Particularly, northern China and Mongolia are prone to climate-induced surface transformations, which were reinforced by the heavily increased numbers of livestock during the 20th century. Extensive overgrazing and resource exploitation amplified regional climate change effects and triggered intensified land degradation that forced policy-driven interventions to prevent desertification. In the past, however, the regions have been subject to continuous shifts in environmental and socio-cultural and political conditions, which makes it particularly difficult to distinguish into regional anthropogenic impact and global climate change effects. This article presents analyses of historical written sources, palaeoenvironmental data, and Normalized Difference Vegetation Index (NDVI) temporal series from the Moderate Resolution Imaging Spectroradiometer (MODIS) to compare landcover change during the Little Ice Age (LIA) and current spectral greening trends over the period 2001–2020. Results show that decreasing precipitation and temperature records triggered increased land degradation during the late 17th century in the transition zone from northern China and Inner Mongolia Autonomous Region to Mongolia. From current climate change perspectives, modern vegetation shows enhanced physical vegetation response related to an increase in precipitation (Ptotal) and temperature (T). Vegetation response is strongly related to Ptotal and T and an increase in physical plant condition indicates local to regional grassland recovery compared to the past 20-year average.

Coastal Erosion Vulnerability in Mainland China Based on Fuzzy Evaluation of Cloud Models

Global climate change-induced sea-level rise and storm wave intensification, along with the large population densities and high-intensity human development activities in coastal areas, have caused serious burden and damage to China’s coasts, led to the rapid growth of artificial shorelines development, and formed a “new Great Wall” of reinforced concrete against the laws of nature. After the last ice age, transgression formed the different features of China’s coast. Depending on the types of geological and landform features, coasts are divided into 36 evaluation units, and 10 indicators are selected from natural aspects (including tectonics, geomorphology, sediment, and storms) and aspects of social economy (population, GDP, Gross Domestic Product), and cloud model theory is used to build a coastal erosion vulnerability evaluation index system in China. The results show that high grade (V), high-middle grade (IV), middle grade (III), low-middle grade (II), and low grade (I) coastal erosion vulnerability degrees account for 5.56, 13.89, 41.67, 33.33, and 5.56% of the Chinese coastlines, respectively. The coastal erosion vulnerability of the subsidence zone is significantly higher than that of the uplift zone. Reverse cloud model and analytic hierarchy process calculation show that the main factors that control coastal erosion vulnerability since the transgression after the last ice age are geological structure, topography and lithological features, and in recent years, the decrease in sea sediment loads and increase in reclamation engineering. Mainland China must live with the basic situation of coastal erosion, and this study shows that the index system and method of cloud modeling are suitable for the evaluation of the coastal erosion vulnerability of the Chinese mainland. This study provides a scientific basis for the adaptive management of coastal erosion, coastal disaster assessment and the overall planning of land and sea.

Sedimentary Dynamics Within the Sedimentary Filling of Sebkha Sidi El Hani, Eastern Tunisia

The Sidi El Hani Wetland is located in Eastern Tunisia. It represents the natural outlet of an endorheic system, Mechertate-Chrita-Sidi El Hani, and it collects all the eroded sediment from this watershed. In this chapter, the visual core description focused on three reference sandy bands and on the concept of grey scale variability in order to infer the clay pan response to the climatic variability and erosion during the last two millennia. First, in the uppermost part, the stage Warming Present (WP) stretches from (1954-80= 1874) to 1993, i.e. ≈120yrs; the establishment of modern conditions is characterized by stable conditions with high grey scale. Added to a small salt crust, this period is dominated by a clayey sedimentation. Second, the stage C4 is called the Late Little Ice Age (Late LIA); it stretches between the 80yrBP and 400yrBP, i.e., 320yrs. It is characterized by intermediate GS values; the clayey sedimentation makes up the twofold and threefold laminates. Based on laser granulometer, the genetic approach shows the interplay of eolian and hydraulic erosion.