*Edited by Nikolay Britun and Tiago Silva*

Low-temperature non-equilibrium gaseous discharges represent nearly ideal media for boosting plasma-based chemical reactions. In these discharges the energy of plasma electrons, after being received from the electromagnetic field, is transferred to the other degrees of freedom differently, ideally with only a small part going to the translational motion of heavy gas particles. This unique property enables the important application of non-equilibrium plasmas for greenhouse gas conversion. While the degree of discharge non-equilibrium often defines the energetic efficiency of conversion, other factors are also of a great importance, such as type of discharge, presence of plasma catalysis, etc. This book is focused on the recent achievements in optimization and understanding of non-equilibrium plasma for gas conversion via plasma modeling and experimental work.

ISBN 978-1-78984-840-3

Plasma Chemistry and Gas Conversion

Published in London, UK © 2018 IntechOpen © Cappan / iStock


*Article* **Late Pleistocene Boulder Slumps Eroded from a Basalt Shoreline at El Confital Beach on Gran Canaria (Canary Islands, Spain)**

**Inés Galindo 1, Markes E. Johnson 2,\*, Esther Martín-González 3, Carmen Romero 4, Juana Vegas 1, Carlos S. Melo 5,6,7,8, Sérgio P. Ávila 6,8,9 and Nieves Sánchez 1**

**Abstract:** This study examines the role of North Atlantic storms degrading a Late Pleistocene rocky shoreline formed by basaltic rocks overlying hyaloclastite rocks on a small volcanic peninsula connected to Gran Canaria in the central region of the Canary Archipelago. A conglomerate dominated by large, ellipsoidal to angular boulders eroded from an adjacent basalt flow was canvassed at six stations distributed along 800 m of the modern shore at El Confital, on the outskirts of Las Palmas de Gran Canaria. A total of 166 individual basalt cobbles and boulders were systematically measured in three dimensions, providing the database for analyses of variations in clast shape and size. The goal of this study was to apply mathematical equations elaborated after Nott (2003) and subsequent refinements in order to estimate individual wave heights necessary to lift basalt blocks from the layered and joint-bound sea cliffs at El Confital. On average, wave heights in the order of 4.2 to 4.5 m are calculated as having impacted the Late Pleistocene rocky coastline at El Confital, although the largest boulders in excess of 2 m in diameter would have required larger waves for extraction. A review of the fossil marine biota associated with the boulder beds confirms a littoral to very shallow water setting correlated in time with Marine Isotope Stage 5e (Eemian Stage) approximately 125,000 years ago. The historical record of major storms in the regions of the Canary and Azorean islands indicates that events of hurricane strength were likely to have struck El Confital in earlier times. Due to its high scientific value, the outcrop area featured in this study is included in the Spanish Inventory of Geosites and must be properly protected and managed to ensure conservation against the impact of climate change foreseen in coming years.

**Keywords:** coastal storm deposits; storm surge; hydrodynamic equations; upper pleistocene; marine isotope substage 5e; North Atlantic Ocean

**Citation:** Galindo, I.s; Johnson, M.E; Martín-González, E.; Romero, C.; Vegas, J.; Melo, C.S; Ávila, S.P; Sánchez, N. Late Pleistocene Boulder Slumps Eroded from a Basalt Shoreline at El Confital Beach on Gran Canaria (Canary Islands, Spain). *J. Mar. Sci. Eng.* **2021**, *9*, 138. https:// doi.org/10.3390/jmse9020138

Received: 23 December 2020 Accepted: 19 January 2021 Published: 29 January 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

#### **1. Introduction**

Evidence for the influence of hurricanes in the northeast Atlantic Ocean during the Late Pleistocene is based on analyses of storm beds preserved on Santa Maria Island in the Azores archipelago [1] and Sal Island in the Cabo Verde archipelago [2]. This line of research follows a growing interest in coastal geomorphology as related to the accumulation of mega-boulders attributed to superstorms or possible tsunami events [3]. Documentation of eroded mega-boulders from rocky shores in Mexico's Gulf of California during the subsequent Holocene [4–6] adds to our knowledge of the physical scope of deposits that can be directly related to historical storm patterns. The Canary Islands in Spain represent seven main islands and numerous islets and seamounts in the North Atlantic located over lithospheric fractures off the northwest coast of Africa, with radiometric dates that vary from 142 Ma to 0.2 Ma along a general east to west axis [7]. At the center of the archipelago, Gran Canaria Island has a volcanic history dominated by subaerial development dating back to 13.7 Ma with successive stages of construction and erosion of the island edifice [8].

The attraction of Gran Canaria for this study is based on a distinctive rocky paleoshore formed by a 3-m thick lava flow exposed laterally along El Confital beach, on the southwest side of La Isleta peninsula, located in the northeastern quarter of Gran Canaria Island. Subaerial flows around several craters preserved atop the Isleta volcanoes exhibit variable Pliocene to Quaternary ages [8], but the basalt shore at El Confital beach is dated to approximately 1 Ma [9,10]. Prior to this contribution, a paleontological study at El Confital beach described an older assemblage of Miocene fossils at one end and a more extensive assemblage of intertidal to shallow subtidal invertebrates confined to the last interglacial epoch attributed to the Eemian Stage, also correlated with Marine Isotope Substage 5e, approximately 125,000 years in age [11]. The goals of this subsequent study include a review of the marine fossil fauna with particular emphasis on species zonation, and with an added emphasis on the extent of encrustations by coralline red algae. Most importantly, this work features extensive analyses of boulders eroded from the paleoshore, among which the Upper Pleistocene biota is preserved. In particular, the physical analyses conducted for clast shape and size are integral to estimates of wave heights based on competing mathematical equations applied to a rocky shoreline composed of joint-bound basalt and hyaloclastite layers.

The range in estimated wave heights extrapolated from average boulder size, contrasted against maximum boulder size at multiple sample sites, suggests that a pattern of repetitious storms is implicated with the coastal erosion of La Isleta and more generally of Gran Canaria Island over an extended period of Late Pleistocene time. The viability of this inference is tested against the historical record of cyclonic disturbances in the eastern North Atlantic Ocean around the Azorean and Canary Islands. Increasing interest in the historical record of storms in this region is available mainly in Spanish-language reports, but also well summarized in the international literature [12]. This approach with reference to historic storms is predicated on a similar analysis of coastal storm beds from the Pleistocene of Santa Maria Island in the Azores [1] as well as coastal boulder beds from the Holocene of Mexico's Baja California [4–6].

#### **2. Geographical and Geological Setting**

Gran Canaria is the third largest and most centrally located island in the Canary Archipelago, situated 150 km off the northwest coast of Africa (Figure 1a,b). With an area of 1560 km2, the island exhibits a circular map outline with an outer perimeter of about 50 km showing a pattern of ravines radiating from the island center at an elevation of 1949 m above present sea level. La Isleta peninsula lies in the northeastern part of Gran Canaria Island, now linked to it by a sandy isthmus about 200 m in width and around 2 km long (Figure 1b,c). Gran Canaria island emerged during the Miocene and reflects a complex geological evolution including the formation and erosion of several stratovolcanoes. Pliocene-Quaternary mafic fissure eruptions were concentrated along the northeastern half of the island. Volcanic activity on La Isleta began during the early Pleistocene with the formation of submarine volcanoes more than 1 Ma ago [9,10]. At least two submarine Surtseyan eruptions separated by marine sedimentary rocks have been identified. The later subaerial phase includes several mafic fissure eruptions (Figure 1c). In El Confital Bay, located off the east-southeast part of La Isleta, erosion has dominated since the middle Pleistocene (>152 ka) and marine, aeolian, and colluvial deposits have been deposited overlying the volcanic sequence (Figure 1d). This area was intensively modified by quarry operation, military activities, and expansion of a shantytown. The clearing of the coastal zone after illegal settlement between 1960 and 1995 and its subsequent elimination by civil authorities, resulted in the area of the deposit encompassed by a larger part of the Confital platform being compromised.

**Figure 1.** Canary Archipelago and features of the centrally located Gran Canaria Island: (**a**) Canary Archipelago with inset showing the position of Gran Canaria; (**b**) central island of Gran Canaria with an arrow pointing to La Isleta on the northern periphery of the island; (**c**) geological map of the volcanic edifice that forms La Isleta with inset box marking El Confital beach (coordinates in UTM m, H28 R); (**d**) map of the kilometer-long beach at El Confital showing seven localities from which sedimentological and paleontological data were drawn for this study. Modified from the 1990 Geological Map by Balcells and Barrera at a scale of 1:25,000 [10].

El Confital bay has a U-shape open to the southwest and is bound on the northeast by an escarpment more than 100 m high. The beach has been developed over a littoral platform (Figure 1c,d) covering approximately 0.1 km2 that consists of highly fractured hyaloclastite tuffs from the submarine stage and volcanoclastic deposits including marine fossils. Parallel to the beach, a basalt cliff line extends parallel to the coast for a broken distance of about a kilometer. Cliffs crop out at an elevation of 1 m in the central part of the area and rise to more than 10 m at opposite ends in the southeast and northwest. In these parts, tuffs are overlain by subaerial lava flows and the cliff reaches a height of more than 10 m.

#### **3. Materials and Methods**

#### *3.1. Data Collection*

Gran Canaria was visited in April 2018, when the organizing author was invited to appraise the beach and rocky shoreline at El Confital beach on the east side of Las Palmas de Gran Canaria. The original data for this study was collected in October 2020 from deposits dominated by basalt boulders consolidated within a limestone matrix. Individual basalt clasts from six stations were measured manually to the nearest half centimeter in three dimensions perpendicular to one another (long, intermediate, and short axes). Differentiated from cobbles, the base definition for a boulder adapted in this exercise is that of Wentworth [13] for an erosional clast equal to or greater than 256 mm in diameter. No upper limit for this category is defined in the geological literature [14].

Triangular plots are employed to show variations in clast shape, following the design of Sneed and Folk [15] for river pebbles. In the field, all measured clasts were characterized as sub-rounded and a smoothing factor of 20% was applied uniformity to adjust for the estimated volume first calculated by the simple multiplication of the lengths of the three axes. Comparative data on maximum cobble and boulder dimensions were fitted to bar graphs to show size variations in the long and short axes from one sample to the next. Comparative data on maximum cobble and boulder dimensions were fitted to bar graphs to show size variations in the long and intermediate axes from one sample to the next. The rock density of basalt from the Pleistocene sea cliffs on El Confital beach is based on laboratory analyses in an unpublished PhD thesis that yields a value of 2.84 g/cm3 [16].

#### *3.2. Hydraulic Model*

Dependent on the calculation of rock density for basalt, a hydraulic model may be applied to predict the force needed to remove cobbles and boulders from a rocky shoreline with joint-bound blocks as a function of wave impact. Basalt is the typical extrusive volcanic rock characteristic of many oceanic islands. Herein, two formulas are applied to estimate the size of storm waves against joint-bounded blocks derived, respectively from Equation (36) in the work of Nott [17] and from an alternative formula using the velocity equations of Nandasena et al. [18], as applied by Pepe et al. [19].

$$Hs = \frac{\left(\frac{\rho\_s - \rho\_w}{\rho\_w}\right)a}{\mathcal{C}\_1} \tag{1}$$

$$\mu^2 = \frac{2\left(\frac{\rho\_s - \rho\_w}{\rho\_w}\right) \lg \left(\cos \theta + \mu\_s \sin \theta\right)}{\mathcal{C}\_1} \tag{2}$$

where *Hs* = height of the storm wave at breaking point; *ρs* = density of the boulder (tons/m3 or g/cm3); *ρw* = density of water at 1.02 g/cm3; a = length of the boulder on long axis in cm; θ is the angle of the bed slope at the pre-transport location (1◦ for joint-bounded blocks); *μs* is the coefficient of static friction (=0.7); Cl is the lift coefficient (=0.178). Equation (1) is more sensitive to the length of a boulder on the long axis, whereas Equation (2) is more sensitive to the length of a boulder on the short axis. Therefore, some differences are expected in the estimates of *HS*.

#### **4. Results**

#### *4.1. Characteristics of the Conglomerate*

Two principal facies of Pleistocene conglomerates occur at El Confital. The first is linked to the background cliffs at opposite ends of the bay and the second is related to the open paleo-platform 5 to 10 m distal from the cliffs in the more central part of the beach. Along the higher cliffs, a marine conglomerate fills paleo-channels and forms ridges trending NNE–SSW perpendicular to the shore (Figure 2a,b). The channel conglomerate is well cemented and consists of coarse-grained (pebble to boulder size) clasts embedded in a white matrix of bioclastic calcarenite. The matrix incorporates marine mollusks and calcareous algae. Commonly reaching a cubic meter in size, boulders are generally ellipsoidal to angular in shape and well rounded. The largest boulders exhibit a long axis in excess of 2 m. Locally, the matrix is composed of reddish sands derived from eroded hyaloclastite tuffs (Figure 2c). Neptunian dykes related to the emplacement of this deposit cut into the tuffs and volcanoclastic deposits filled with carbonates and zeolites as well as bioclasts and gravels (Figure 2d). The more distal conglomerate is deposited nearly horizontal across the shore platform. Here, boulders are smaller and more rounded, and the matrix consists of coarse-grained bioclastic sand.

**Figure 2.** Conglomerate slumps above El Confital beach south of La Isleta; (**a**) incision approximately 3.5 m deep in cliff face filled with basal boulders loosened from the adjacent basalt formation (backpack for scale); (**b**) boulder-filled cut in the same cliff face with individual boulders exposed in bas relief (the largest boulder at the bottom has a long axis of approximately 75 cm); (**c**) reddish sands derived from eroded hyaloclastite; (**d**) details showing filling of a neptunian dyke and syndepositional fractures in basalt (tape-measure case for scale).

#### *4.2. Comparative Variation in Clast Shapes*

Raw data on clast size in three dimensions collected from each of six sample sites are recorded in Appendix A (Tables A1–A6). Regarding shape, points representing individual cobbles and boulders are fitted to a set of Sneed-Folk triangular diagrams (Figure 3a–f). The spread of points across these plots reflects a consistent pattern in the variation of shapes from one sample to another. As few as one to three points fall within the upper triangle in each diagram, which represents an origin from a perfectly cube-shaped endpoint as a jointbound block of basalt. No more than five points from each sample fall within the lower, right-hand rhomboid in these diagrams. This extreme corner signifies elongated blocks with one super-attenuated axis in relation to two axes that are significantly shorter by 75% or more. The result is a bar-shaped piece that originated as a joint-bound block of basalt. The plot with the greatest number of points in these two extremes is from locality 5 (Figure

3e), from a position closer to the western end of the paleoshore. Numbering between 10 and 15 per sample, the majority of points from each of the six samples fall within the central two rhomboids directly below the top triangle. Such points clustered at the core of a Sneed-Fold diagram are typical of clasts for which two of the three dimensions are closer in value than the length of the third axis. It is notable that no points appear anywhere along the margin of rhomboids on the left side of these diagrams. It is clear that no tendency in shape towards plate-shaped clasts is evident in the data. The general slope of points in agreement from the six plots follows a uniformly diagonal trend from the top to the lower right-hand corner. The trend in distributed points from these plots signifies the rounding of clasts in which two of the dimensions (maximum and intermediate lengths) are more closely matched with the third as an outlier.

**Figure 3.** Set of triangular Sneed-Folk diagrams used to appraise variations in cobble and boulder shapes sampled along the Upper Pleistocene paleoshore east to west at El Confital beach south of La Isleta: (**a**–**f**) sample localities 1 to 6 represented, respectively.

#### *4.3. Comparative Variation in Clast Sizes*

Drawn from original data (Tables A1–A6), clast size is plotted to the best effect on bar graphs as a function of frequency against maximum and intermediate lengths of the two longest axes perpendicular to one another. The dozen graphs plotted (Figure 4a–l) exhibit trends in clast size sorted by intervals of 15-cm, in which the boundary between cobbles and boulders is embedded within the range for clasts between 16 and 30 cm in diameter. The left-hand column (Figure 4a,c,e,g,k) depicts lateral variations in maximum boulder length from the six samples on an east to west transect along the Upper Pleistocene paleoshore. Overall, each of the samples in this dimension is numerically dominated by boulders in contrast to cobbles at ratios from 3:2 and 4:1. Samples from the east end (Figure 4a,c) reflect differences that conform to a normal bell-shaped curve, whereas samples from the west end (Figure 4i,k) are strongly skewed to include a few boulders of extreme size in excess of one meter. In contrast, the right-hand column (Figure 5b,d,f,h,j,l) shows lateral variations in values for intermediate length of clasts. In all but two examples (Figure 4f,j) the number

of measurements falling within the interval of 16 to 30 cm exceeds those registered for the same interval as measured for the long axis. This result reflects a general shift in size to smaller frequencies compared to the left-hand column and confirms the diagonal trend in shapes illustrated by the Sneed-Folk diagrams (Figure 4a–f). Skewness that mirrors the inclusion of extra-large clasts is especially evident in the bar graphs at the extreme ends of the paleoshore (Figure 4b,l). The largest basalt clast identified in the entire project registered a long axis of 214 cm, an intermediate axis of 94 cm, and short axis of 50 cm (Table A6).

**Figure 4.** Set of bar graphs used to contrast variations in maximum and intermediate boulder axes from six samples at El Confital beach south of La Isleta: (**a**,**b**) bar graphs from locality 1; (**c**,**d**) bar graphs from locality 2; (**e**,**f**) bar graphs from locality 3; (**g**,**h**) bar graphs from locality 4; (**i**,**j**) bar graphs from locality 5; (**k**,**l**) bar graphs from locality 6.

**Figure 5.** Examples of abundant marine fossils from the paleoshore exposed at El Confital beach: (**a**) filling among larger boulders that includes the elbow shell (*Patella aspera*) and barnacles (*Balanus trigonus*) with bottlecap for scale; (**b**) bivalve (*Chama gryphoides*) with pen-tip for scale; (**c**) gastropod (*Gemophos viverratus*) with 3-cm scale; (**d**) gastropod (*Cerithium vulgatum)* with scale bar = 1 cm; (**e**) large colony of gastropods (*Dendropoma cristatum*) with rock hammer for scale.

#### *4.4. Paleontological Inferences on Water Depth*

A moderately rich molluscan fauna of 42 marine gastropods and eight bivalves from El Confital (Table 1) that also includes barnacles and rhodoliths formed by coralline red algae is maintained in the permanent collections of the Tenerife Science Museum. Overall, these fossils reflect organisms that lived under inter-tidal to shallow subtidal conditions as confirmed by outcrop relationships, where currently the fossil remains are visible cemented in place along small sections of the bay and in ravines that form after heavy rains. The Pleistocene fauna at El Confital corresponds to a high-energy setting against a rocky shore highlighted by the abundance of mäerl and rhodoliths associated with relatively abundant patelid gastropods (Figure 5a), chamid bivalves (Figure 5b), and other mollusks (Figure 5c,d). Extensive colonies of vermetid gastropods (*Dendropoma cristatum*) are represented as discrete biological clasts incorporated within the conglomerate (Figure 5e). Although extensive shell fragmentation is evident, it is worth noting the high rate of complete shells, which include delicate ornamentation. In the case of pateliform shells, preservation also features evidence for stacking. This taphonomic trait is characteristic of a high-energy regime. At the base of the deposit on the platform at El Confital (Figure 2, locality 7), there is evidence of bioturbation possibly related to the activity of crabs. Also, trace fossils likely related to the activity of polychaets are preserved within the neptunian dykes that are common on the platform.

**Table 1.** Summary species list of epifaunal, infra-intertidal invertebrates from the Upper Pleistocene strata exposed at El Confital beach correlated with Marine Isotope Substage 5e. Extinction is denoted by asterisk.

In addition to preservation of whole but also fragmented rhodolith debris (Figure 6a,d) that signify the remains of a Pleistocene mäerl bed at El Confital, deposits are notable for the conglomerate consisting of mixed basalt cobbles and large boulders that exhibit erosional smoothing. The growth of coralline red algae in thin layers encrusted around and among these basalt clasts is widespread (Figure 6). In some examples, algal crusts are localized

and fail to completely surround individual cobbles leaving some parts free as viewed profile (Figure 6a). This scenario implies that some clasts were only partially coated by crustose algae elsewhere and subsequently were transferred to the conglomerate. In other examples, thick growth of algal crusts completely fills voids between boulders and small cobbles fixed in between (Figure 6b). This suggests an alternative scenario in which algal growth occurred perhaps on the outer margin of the conglomerate after its mass accumulation. Crustose red algae also are found in patches attached to basalt boulders exposed in three-dimensional relief (Figure 6c).

**Figure 6.** Examples of basalt cobbles and boulders heavily encrusted by coralline red algae: (**a**) space between two adjacent boulders filled by algal-encrusted cobbles and pebbles (scale bar = 2.5 cm); (**b**) close-up view of thick algal encrustations in the space among basalt clasts (bottle cap for scale); (**c**) hat-size basalt boulder with remnants of coralline red algae (clasp on hat string = 3 cm).

#### *4.5. Storm Intensity as a Function of Estimated Wave Height*

Clast sizes and maximum boulder volumes drawn from the six field localities are summarized in Table 1, allowing for direct comparison of average values for all clasts, as well as values for the largest clasts in each sample based on Equations (1) and (2) derived from the work of Nott [16] and Pepe et al. [19].

The Nott formula [17] shown in Equation (1) yields an average wave height of 4.5 m for the extraction of joint-bound blocks from basalt sea cliffs exposed at El Confital beach and their subsequent transfer as slump boulders in samples 1 to 6. A much larger value for a wave height of 11 m is derived from the average of the largest single blocks of basalt recorded from the six locations. More sensitive to clast length from the short axis, the more sophisticated Equation (2) from Pepe et al. [19] yields values that are consistently lower for the estimated average wave height and estimated maximum wave height. The difference between the two calculations for estimated average wave height as well as estimated maximum wave height is, however, very small at 30 cm. Notably, the value for average maximum wave height derived from Equation (1) from Nott [17] is 2.5 times as high as the value found for overall average wave height using the same formula. Essentially the same factor applies to the slightly lesser values derived from Equation (2) according to Pepe et al. [19]. Clearly, the hydraulic pressure with extreme wave impact is necessary to loosen and budge the largest fault-bound blocks of basalt in the Pleistocene cliff line, as represented by the enormous block at locality 6 estimated to weigh 2.25 metric tons (Table A6). The essential issues under consideration in the following sections pertain to the singularity of a lone event of extreme magnitude as opposed to the repetition of many, but less energetic events in the shaping of the Pleistocene boulder slumps at El Confital beach.

#### **5. Discussion**

#### *5.1. Integration of Paleontological and Physical Data*

Boulders derived from horizontal layers of joint-bound basalt that originated as a subaerial flow about 1 million years ago at El Confital are estimated to have undergone wear that resulted in a 20% reduction in volume from more cubic or bar-shaped blocks (Figure 4) due to mutual friction under wave shock and subsequent erosion that smoothed sharp corners. Pleistocene fossils incorporated within the resulting conglomerate (Table 1, Figure 5) reflect an age correlated with Marine Isotope Stage 5e during the last interglacial epoch [11,20–23].

The assemblage represents a high-diversity, intertidal to shallow subtidal fauna dominated by mollusks that thrived on a basalt shelf on the southern margin of a small volcanic edifice. Except for those few limited to the MIS5e, most of the species listed in Table 1 continue to inhabit the contemporary coasts of the Canary Islands. These taxa are characterized by a preference for rocky or mixed littoral bottoms (sandy with rocky clasts of different sizes) up to a depth of about 3 m within the intertidal zone. The various species occupy different niches, such as crevices or intertidal pools or beneath rocks, which provide protection from the intense northwesterly waves that dominate the shores of the Canary Islands. In the case of El Confital today, there also occurs a wide rocky intertidal flat with little slope. In these shallows, the organisms are grouped in parallel bands or remain associated with pools at low tide, depending on their ability to adapt to environmental factors such as desiccation, temperature, salinity, and water agitation that condition life in that environment [23]. The intertidal shallows are home to a high number of marine organisms, highlighted by the dominant populations of pateliform and trochid gastropods.

Some of the larger clasts and boulders are encrusted with crustose red algae exhibiting rinds in excess of a centimeter in thickness (Figure 6). In places, surviving patches of red algae retain a rose coloration typical of coralline red algae (Figure 6c), but it may be due to inorganic discoloration. In addition to platy red algae cemented directly onto cobbles and boulders, whole rhodoliths and the debris of broken rhodoliths occur in pockets scattered throughout the conglomerate (Figure 5a). Some faunal elements may have lived within the interstices of adjacent boulders after the conglomerate was formed during slump events. Platy red algae are concentrated unevenly on the sides of cobbles and smaller boulders (Figure 6a), leaving other faces vacant. Some open spaces between adjacent boulders appear to have been filled by the continual growth of crustose red algae (Figure 6b). On the other hand, rhodoliths potentially composed of the same species of coralline red algae in unattached growth forms expressed by spherical shapes would have expired due to a lack of mobility.

A proper survey has yet to be undertaken to identify the genera and possible range of species belonging to coralline red algae that encrust cobbles and boulders in the Upper Pleistocene deposits at El Confital. Such a study necessarily entails the collection of samples for the making of thin sections transversely through crusts in order to identify features diagnostic at least on a genus level. Until such time, the best that can be said is that the present-day distribution of marine algae is widespread throughout the Canary Islands and keyed to habitats around individual islands in the Canary archipelago. Among the Corallinaceae known to be specific to Gran Canaria island, at least five genera are present, including *Hydrolithon*, *Lithophyullum*, *Lithoporella*, *Mesophylum*, and *Neogoniolithon*. Among these, *Lithophyllum* is the most diverse with four species locally attributed to that genus around the island [24]. From a paleoecological point of view, what is most telling about the boulder beds at El Confital at this stage of investigation is that they came to reside in shallow water within the upper photic zone consistent with the associated fossil fauna.

Overall, the combination of paleontological and physical evidence points to an open shelf setting on the margin of a small volcano around which a distinctly shallow-water biota thrived prior to interruption by storm events that eroded a series of parallel channels perpendicular to the strike of the paleoshore. These submarine gullies define the depositional space in which the Upper Pleistocene conglomerate was accommodated and preserved (Figure 3a,b).

Based on the application of two competing mathematical models that consider different dynamics [17,19], the estimated average height of storm waves that broke onto the south shore of La Isleta are remarkably similar in the range between 4.2 and 4.5 m (Table 2). However, the largest half-dozen boulders sampled from six study sites yield a much higher average estimated height of storm waves between 10.8 and 11.1 m (Table 2). Under any circumstances, such results would represent extremely large waves. These numbers represent clear outliers in the data, although based on boulders of extraordinary size and weight up to 2.25 metric tons. It may be that lesser waves were instrumental in gradually loosening the biggest basalt blocks from a joint-bound condition to a point where gravity slid them into nearby channels enlarged by multiple storm events. Rare hurricane events are more likely to have generated storm waves on the order of 6 to 8 m that impacted the Pleistocene rocky shore at El Confital. An entirely different set of equations is used to estimate the landward onrush of water due to tsunami events, but the complete absence of basalt boulders on the slopes of La Isleta (Figure 2) mitigates against this scenario.

**Table 2.** Summary data from Appendix A (Tables A1–A6) showing maximum bolder size and estimated weight compared to the average values for sampled boulders from each of the transects together with calculated values for wave heights estimated as necessary for boulder-beach mobility. Abbreviations: EAWH = estimated average wave height, EMWH = estimated maximum wave height.


**5.1 Spetzler-Martin (S-M) grading**

In 1986, Spetzler and Martin introduced the most commonly used grading scale for cAVMs; it uses three anatomical features of AVM (nidus size, nidus location relative to the eloquent brain (**Figure 10**), and pattern of venous drainage) to generate five cAVM grades (**Table 1**).

To determine S-M grade of cAVMs, size of the nidus, venous drainage, and eloquence of adjacent brain tissue are determined in angiography, brain CT scan, and/ or MRI of the brain. A numerical value is assigned for each category, as described in **Table 1**. The grade is derived from adding the points awarded for each category; for example, for grade I, the lesion would be small (less than 3 cm/1 point), in noneloquent region (0 point), and have only superficial drainage (0 point) (**Figure 11**); therefore, excision of such lesion would be complete, minimally invasive, and associated with low surgical complications. Whereas for grade V, the lesion would be large (more than 6 cm/3 points), sited within or immediately close to eloquent brain

#### **Figure 10.**

*The anatomic areas considered neurologically eloquent. (A) Deep eloquent area (hypothalamus, thalamus, brain stem, and cerebellar peduncle). (B) Eloquent area in cerebral cortex (sensory-motor, primary visual, and language area) [19].*

#### **Table 1.**

*Spetzler-Martin (S-M) grading scale is used to make decisions about treatment risks.*

#### **Figure 11.**

*Grade I AVM; (A) Vertebral angiograms. (B) Anteroposterior view cerebellar AVM less than 3 cm (1 point), superficial on cerebellar cortex (0 point), superficial drainage (through superficial cerebellar hemisphere veins–arrows: 0 point) [19].*

(1 point), and venous drainage would drain into deep venous system (**Figure 12**), so excision of such lesion is extremely difficult and associated with significant risk of bleeding and surgical morbidity and mortality. Moreover, obliteration of large cAVMs leads to sudden increase in perfusion, which leads to vasogenic edema or hemorrhage (normal perfusion pressure break through phenomenon). There are certain lesions that should not be considered for surgery such as large AVM that invades eloquent critical area or diffuse nidus that involves crucial structure such as hypothalamus or brain stem (**Figure 13**), so the surgical resection of such lesions would necessarily be associated with significant neurological deficit or death. These AVMs are graded under separate category (grade VI) and considered as inoperable AVM [22, 23].

The S-M grading scale was introduced to predict the outcome of surgical resection but can also be used to predict the radiosurgical outcome. Lower grades (grades I and II) are associated with a good result and less postoperative neurological deficit in comparison with grades IV and V [21–23].

Multiple retrospective studies showed that rates of poor outcome were highly correlated with S-M grade. Precisely, rates of poor outcome were calculated as follows: S-M grade I = 4% (95% CI, 2–7), S-M grade II = 10% (95% CI, 7–13), S-M

#### *Cerebral Arteriovenous Malformations (cAVMs): What Is New? DOI: http://dx.doi.org/10.5772/intechopen.90096*

grade III = 18% (95% CI, 15–22), S-M grade IV = 31% (95% CI, 25–37), and S-M grade V = 37% (95% CI, 26–49). These results prove that microsurgical resection is suitable for low-grade cAVMs (S-M grades I and II), whereas surgical resection of high-grade cAVMs (S-M grades IV and V) is associated with a high risk of poor patient outcome. Lawton and Davies et al. subcategorized grade III into three groups based on a specific combination of the same anatomical features (size, location, and venous drainage) to improve prediction of treatment outcome:

Group 1: Patients with S-M grade III cAVMs (a combination of small size, eloquent location, and deep venous drainage) have surgical outcomes similar to those of S-M grades I and II.

#### **Figure 12.**

*Grade VAVM; (A) Carotid angiogram, arterial phase. (B) Venous phase, AVM greater than 6 cm (3 points), situated in corpus callosum with a deep thalamic component (eloquent: 1 point), draining into a hugely dilated internal cerebral vein (deep drainage–arrow 1 point) [19].*

#### **Figure 13.**

*Grade IV AVM (inoperable AVM), (A) Vertebral angiogram, anteroposterior view. (B) Lateral view, arterial phase this lesion fed by multiple vessels from rostral basilar artery, surrounding and invading the mesencephalon [19].*

#### **Table 2.**

*Supplementary Spetzler-Martin or Lawton-Young cAVM grading scale.*

Group 2: Patients with S-M grade III cAVMs (a combination of medium size, noneloquent location, and deep venous drainage) have a poor surgical outcome similar to that of S-M grades IV and V.

Group 3: Patients with S-M grade III cAVMs (a combination of medium size, eloquent location, and superficial venous drainage) have a poor surgical outcome similar to that of S-M grades IV and V [23].

Supplementary grading scale to traditional S-M grading scale was proposed in 2010 to enhance its predictive power for predicted outcomes after surgical resection of cAVMs. This supplemental scoring system added three factors that affect patient's outcome (age, hemorrhagic presentation, and nidus configuration) (**Table 2**). The supplementary grading scale named Lawton-Young supplementary grading scale has been authorized in a separate cohort of 1009 patients [21, 23].

#### **6. Treatment of cAVMs**

Complete resection or obliteration of the nidus and AV shunt is considered as the treatment of choice of cAVMs. Incomplete nidal resection does not decrease hemorrhage risk. However, There are few reports of partial resection may improve neurological symptoms in patients who have neurological symptoms related to hemodynamic. There are three complementary therapeutic techniques that have been developed to achieve these goals (microsurgery ± embolization, stereotactic radiosurgery, and embolisation). The treatment plans of cAVMs should be carefully taken by a multidisciplinary team of knowledgeable and skilled physicians. They should take the size, location, and vascular features of the AVM in consideration. Moreover, risks of significant complications such as short- and long-term hemorrhage risk, feasibility, associated aneurysm, patient's age, risks of intervention, availability of interventional radiologist, and size and compactness of the nidus should be assessed. The short- and long-term hemorrhage risk is associated with a history of raptured cAVM, patient age, AVM location, size, and vascular morphological features [23–25].

Children and young adults have a long life expectancy, and the risk of intracerebral hemorrhage (ICH) is gradually increasing over the years. Therefore, curative therapy and complete obliteration are recommended whenever possible, while conservative treatment may be considered for elderly patients. The cumulative risk of hemorrhage can be calculated by the formula: lifetime risk of hemorrhage = 1 – (1 − P) × N (N is the expected years of life remaining, and P is the annual probability of hemorrhage). Another more straightforward formula is as follows: lifetime risk of hemorrhage = 105-patient's age in years.


**2.3 Analytical sample**

For this analysis, we only used the ABCD baseline sample. We included the ABCD study regardless of their race, ethnicity, and psychopathologies [81]. However, we limited the sample to those who had complete data on our variables and met satisfactory imaging quality. Our analytical n for the analyses \*presented here is 7959.


*3.1. Chemical Characterization*

The proximate composition and fatty acid profile for *Rhus coriaria* from Sicily are reported in Tables 1 and 2, respectively.

**Table 1.** Proximate composition of *Rhus coriaria* from Sicily.

ND, not determined.

These results show that sumac represents a source of dietary fiber, which may be useful for relieving gastrointestinal upset [30].

In line with previous studies, fats represent the second most abundant compounds [5,9]. The fatty acid composition is reported in Table 2. As it can be observed, sumac fruits contain 65.09 ± 1.67% of polyunsaturated fatty acids, and the contents of linoleic (omega 6)

and α-linolenic acid (omega 3) are 30.82 ± 1.21% and 1.85 ± 0.07%, respectively. This result confirms that this fruit could represent a source of unsaturated fatty acids, as previously reported [9]. Furthermore, oleic acid is the most abundant fatty acid, representing 31.67 ± 1.29%.

**Table 2.** Fatty acid profile of *Rhus coriaria* from Sicily.

Total phenolic and total anthocyanin contents of *R. coriaria* extract are 71.69 ± 1.23 mg/g as gallic acid equivalent, and 6.71 ± 0.12 mg/g as cyanidin-3-O-glucoside equivalents,respectively. These two classes of compounds in sumac are the principal constituents responsible for its phytochemical activity. *R. coriaria* is, hence, a source of healthy substances and is useful in various fields and applications.

In agreement with a previous study [31], our results confirm that sumac is a good source of minerals, so it could be a suitable tool to increase dietary mineral intake. As reported in Table 3*, R. coriaria* is mainly rich in potassium, calcium, magnesium, and phosphorus, followed by aluminum, iron, sodium, boron, and zinc.

**Table 3.** Mineral elements (mg/kg) in *Rhus coriaria* fruits powder.

The polyphenolic composition of methanolic sumac extract is reported in Table 4. The total polyphenols account for 71.69 mg/g. The flavonoids and phenols represent 18.48% and 81.52%, respectively. The first component identified was gallic acid, followed by quercetin, methyl digallate, pentagalloyl-hexoside, and kaempferol 3-O-glucoside.


**1. Introduction**

Pakistan is the fifth most populous and developing economy, with a population of over 22.50 million. The world's best irrigation system lies in Pakistan and 80% of the country's population lives in the Indus Basin. Despite this, Pakistan has become a water-stressed country and, as per the estimates of the United Nations (UN), the availability of per capita water in Pakistan is 1090 m3 [1,2]. The agricultural sector has been the key contributor towards the economic developments of the country since it achieved independence. The contribution of the agricultural sector to GDP of Pakistan during FY 2021–22 was around 22.7%, comprising 37.4% of the labor force [3]. The agricultural sector and water resources are under immense pressure, as the population of the country is increasing 2.6% [4]. The increasing population demands more food, which requires more areas to be cultivated. The Pakistan Council of Research in Water Resources (PCRWR) have intimated that a water shortage is expected by 2025 if no new water reserves are constructed. Farmers are fulfilling their agricultural water needs by overexploiting ground water. The poor quality of ground water is resulting in salinization, which is an alarming concern for

**Citation:** Zahra, S.M.; Shahid, M.A.; Misaal, M.A.; Zaman, M.; Imran, M.; Azam, S.; Hussain, F. Sustainable Water Management in Indus Basin and Vulnerability Due to Climate Change. *Environ. Sci. Proc.* **2023**, *25*, 36. https://doi.org/10.3390/ ECWS-7-14203

Academic Editor: Luis Garrote

Published: 14 March 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

sustainability of agriculture in Pakistan [3]. Pakistan is among the list of countries which are significantly affected by salinity. Conjunctive management practices of ground and surface water can increase the irrigation effectiveness and efficiency [4]. About 70% of irrigated plains are using ground and surface water simultaneously. With the growing economy, the distribution and management of irrigation waterways is a serious concern for the future. The municipal and industrial supplies in urban areas are predicted to reach 14 km3 from 5.3 km3 by 2025 [1] and per capita water availability will be reduced by 32%, resulting in a food shortage of 70 million tons [5]. The Indus Basin was designed to supply low-intensity irrigation in large areas of canal command. The increase in cropping intensity is increasing the gap in supply demand and creating incessant unrest.

Climate change is one of the worst developments of that century, and has significantly affected water supply and cropping patterns. Glacial melt and retreat, change in precipitation patterns, and snow melt are the most frequently observed uncertainties resulting from climate change. About 45% of basin flow is generated by snow and glacial melt, which indicates that vulnerability to climate change is very high. The Hindu Kush Himalaya (HKH) range is widespread over 2000 km2 in the Asian continent and contains rivers such as the Brahmaputra, Indus, and Ganges. Almost 1 billion people in Nepal, India, Bangladesh, Pakistan, China, and Bhutan are dependent on these rivers. Recent studies have predicted that glacial melt will be increased due to global warming, which can increase the river flows by 40% [6], but the average flow rates will be decreased by 60% in Indus Basin [7]. The duration between May and September accounts for 85% of discharge in the Indus Basin in form of snow and glacial melt and monsoon activity. The hydrological cycles are expected to change, as the floods of 2010 and 2022 are examples of a hydrological system [8]. Therefore, there is a need to adopt and implement water management techniques, the building of new reservoirs for water storage, and the allocation of water resources in an optimum way. Additionally, mitigation measures are needed to tackle the effects of climate change to ensure water and food security and safety in Pakistan.

### **2. Materials and Methods**

### *2.1. Study Area*

The area of the Indus Basin is 566,000 km2 and spread over four provinces of Pakistan, i.e., Punjab, Khyber Pakhtunkhwa, Baluchistan, and Sindh. The basin length of Indus is about 2900 km. It is fed by the eastern (Sutlej and Ravi) and the western (Chenab, Kabul, and Ravi) rivers, as shown in Figure 1. The river flows through an elevation of 18,000 ft from the Himalayas to the plains of Sindh and discharges into the Arabian Sea. The Indus Basin in Pakistan has a mean annual flow of 176 billion m3 and 90% of the flow is used for irrigation purposes. The irrigation network consists of the main, branch canal, and distributaries with a length of about 57,000 km, with 88,600 outlets.

**Figure 1.** Digital elevation model of Indus Basin with dams, rivers, and flood-affected areas.

### *2.2. Data Collection and Analysis*

Pakistan is one of the most climatically varied countries due to its wide temperature range, which includes extremes such as the Sahara desert's temperature and the arctic cold of Alaska. Data on extreme events of climatic parameters, i.e., temperature and precipitation, were collected for the duration of 1919–2022. The data were collected from the World Meteorological Organization (WMO) [9] and Pakistan Meteorological Department (PMD) [10]. The collected data were processed in GIS to highlight the main areas in which extreme events occurred. As per the intensity of extreme events, the hot spotted areas were graded using Inverse Distance Weighing (IDW) method.

### **3. Results and Discussion**

### *3.1. Sustainability of Water*

Pakistan is the fifth most populous country in the world, with a population growth rate of 2.6%; its population is expected to reach 250 million by 2025 [4]. The urban population of Pakistan comprised 37% of the country's population in 2017, and this is expected to reach 52% by 2025 [5]. The movement of the population towards cities will increase water consumption by 8%. The per capita water availability in Pakistan was 5000 m3 in 1947, which was reduced to 1100 m3 in 2005 and is predicted to drop to 800 m3 by 2025 [5]. According to the estimates of the UN, the water demand in Pakistan is increasing by 10% per annum. The area-wise water withdrawal in Pakistan is calculated as 175 km3, of which around 71% (124.25 km) is from surface water and 29% (50.75 km) is from groundwater [8]. In Pakistan, surface water has always been a burning topic, but groundwater has also many problems associated with it, i.e., salinity, overdraft, and waterlogging. According to an estimate, there are 0.8 million pumps installed in Pakistan and 50% of agricultural water needs in Punjab are met by them. The over-pumping of groundwater has led to the salinization of 4.5 million hectares; about 50% of the area lies in irrigated plains of the Indus Basin. The inappropriate irrigation practices and waterlogging due to seepage from unaligned canals have affected nearly 1 million hectares of irrigated plain of the Indus Basin, but the problem of salinity is worse in Sindh. The curative measure was taken to counter the problem of salinity, but proved to be futile, and the land productivity badly decreased. The water storage capacity of Pakistan is considerably lower than that of developed countries. The per capita water availability in US and China is 5000 and 2000 m3, respectively, while it is 150 m3 in Pakistan [1]. The storage capacity of Pakistan is only 30 days, while our neighboring country India has 120 to 220 days. The maximum storage capacity of water, i.e., 900 days. The storage capacity of any country depends upon its reservoirs. Pakistan has only two main reservoirs, i.e., Tarbela and Mangla, and the capacity of both reservoirs has been reduced by 20 and 32% due to sedimentation [5]. The Lieftinck report of 1968 stated that one Tarbela-sized reservoir every 10 years is necessary to meet the increasing demands of agriculture. It is also recommended to increase the storage capacity to 22 billion m3 by 2025 to meet the projected requirement of 165 billion m3. If no new reservoirs are developed, the water availability will be reduced by 12% by the next decade due to sedimentation. Another reason for the development of new reservoirs is the increasing industrialization and urbanization, which demands more energy to fulfill their needs.

### *3.2. Extreme Events*

Extreme high and low temperatures, as well as the heaviest rainfalls, are all features of Pakistan's weather. In Turbat, Balochistan on 28 May 2017, a record-breaking 53.7 ◦C was measured, making it the hottest day in Pakistan's history [11]. On 26 May 2010, at Moenjo Daro, Sindh, Pakistan, a temperature of 53.5 ◦C was recorded, making it the second-hottest day in the country's history [12]. This was the fifth-highest temperature ever reported on Earth. On 23 July 2001, Islamabad received 620 mm of rain, the largest amount ever recorded rainfall in just 10 h.


**2. The story of human resolve**

As much as we must acknowledge that humanity was deeply humbled by the ongoing pandemic, and that all-too-frequently we had to re-learn the collective lessons of declaring premature victory, we also need to emphasize the story of human resolve and our ability to "rise to the occasion" when facing overwhelming odds [5, 7–9]. The COVID-19 pandemic taught us much about being a true "global community" [10]. Within this general context, a thorough evaluation is warranted of the relationship between COVID-19 and IHS, including a detailed examination of all pertinent domains that directly or indirectly influence our ability to maintain human health and wellness. Using the expanded definition of 'health security' in the context of a global pandemic is especially important and central to highlighting the real-time impact of an emerging infectious disease (EID) on multiple other spheres of human life, with medical and direct healthcare aspects constituting only a small proportion of factors able to actively modulate wellness and health across the planet [11–18]. In fact, one might argue that a more comprehensive, inclusive, and multidimensional approach to the current pandemic contributed to a significant reduction in both human and economic costs of this once-in-a-century global event. And even more importantly, the above is a true reflection of human resolve and a testament to our collective accomplishments when we all work together as a community.

### **3. The COVID-19 pandemic as a transformational event**

Global challenges, including a devastating pandemic, often force our existing systems, established patterns, and the way we operate in general, to rapidly evolve and change in response. While it is generally acknowledged that there is often an inherent "reluctance to change," especially in the presence of contentment with the *status quo*, major transformational events are defined as such because they mandate change – and often in ways that are difficult to initiatially anticipate. Thus, the initial change can be – quite understandably – reactive. However, the longer-term response to the pandemic tends to be more deliberate as well as more constructive. This is especially true in the context of research, development, and distribution of therapies, vaccines, therapeutic devices; an acknowedgmet of treatment limitations that are assessed within an ethical framework; as well as serious consideration of cultural, religious, and family centered approaches [19, 20].

#### **4. Technology-driven transformation of healthcare**

The early pandemic created a perfect milieu for various existing technologies to enter mainstream implementation and use [21]. Two particular technological advances worth mentioning in this context, both already well in the state of "transition into mainstream" irrespective of the ongoing pandemic, are tele-health and artificial intelligence [22, 23]. At the same time, the adoption process of novel technologies and approaches must also ensure that we carefully factor in appropriate patient safety considerations, any potential limitations, well-defined staff responsibilities, evolution of team roles, as well as adherence to protocols [24]. While such technologies very quickly become a part of the modern medical lexicon, widespread acceptance was often challenged, not just by individual human reluctance or aversion, but also by the simple reality that such digitial tools, despite the need for rapid and widespread implementation, have not quite matured for the intended role(s) they were originally conceived to fulfill.

*Introductory Chapter: International Health Security in the Era of COVID-19 DOI: http://dx.doi.org/10.5772/intechopen.98691*

#### **5. Post-pandemic recovery: toward sustainable future**

Although current events make it challenging to clearly picture the post-COVID-19 future, it is likely just a matter of time before we enter this new and eagerly awaited "state of the planet." It will hopefully be a state where politics, economic health, violence, acute and chronic disease, racial disparities, health care access, the viability of health care systems, delivery of care, mental health, homelessness, and aging are seriously re-evaluated and addressed. It will be critically important that this future is constructed in a manner that The United Nations proposed in their landmark document discussing 17 sustainable goals for the future [18]. These suggestions are a roadmap to assist in overcoming challenges such as poverty, environmental concerns, various socio-economic injustices, the climate change, among other agenda points. Within this context, we must ask, "Is the social, economic, and political infrastructure of the planet ready for such demands?" There is no doubt that community participation on local, regional, national and international levels will be necessary for a successful and sustainable outcome for the planet and for the humanity [25]. Of additional importance, it is also vital that the knowledge of pandemic preparedness fundamentals becomes an established competency for those holding or running for political office, where ignorance and complacency toward implementing viable solutions for problems with established political, social, economic, and scientific evidence is simply not acceptable [5].

#### **6. Humans and humanity**

As the pandemic continues beyond 2020 the world will likely see an imbalance between the vaccinated and the unvaccinated, the 'pro-maskers' and the 'antimaskers,' the believers of science and the non-believers of science, the true warriors (health workers on the ground) and the media warriors (the speakers in media), the false news mongerers and the seekers of truth [11, 26, 27]. As we battled to save lives, the pandemic tested our resilience at an individual level and also tested our values as a global society. Sharing, caring, supporting, collaborating, empathy, compassion, resilience and resolve were actively tested, every minute of every day, at every location, and for every human being. Food, water, hospital beds, medications, and oxygen were simultaneously in high demand and in short supply [22].

Across intensive care units on every continent, critically ill patients fought for every breath, fought to live, fought for another opportunity to be with their loved ones. The entire humanity was fighting to survive as COVID-19 mercilessly affected individuals, families, nations, political and economic spheres. The pandemic changed geopolitical relationships, industry partnerships and economic projections. It changed and will continue to change the way things humans do well into the future, and potentially forever across some domains (e.g., pandemic preparedness and management) [5, 22].

When looking at the COVID-19 pandemic events from a truly global and comprehensive perspective, it is a giant test of how humans approach and embrace international health security. In the context of 'health security,' the actual degree of security is closely related to the overall degree of 'health insecurity' that exists around us. Maintenance of health security requires ongoing efforts and a constant focus on all mission-critical elements [18]. As this herculean task is being undertaken, the attainment of 'health security' thus becomes a careful balancing act that involves politics, competing interests, social, and economic considerations. Humanity plays a major role when we evision a 'secured world.' Here, IHS should be considered to be universal, and it should be the main sustainable goal that humans

should strive to attain and work toward consistently. As such, 'health security' is a long journey with only a few periodic punctuations that provide just enough time for self-reflection and re-orientation.

## **7. Synthesis**

Within the expanded IHS framework, the repose to the current pandemic has been a kind of one-size-fits-all public health policy without a strategic assessment of the local and regional situation. The relatively diminished capacity of peripheric surveillance and control systems has forced local governments to 'copy and paste' control strategies from abroad [22, 28]. However, when pursuing such course, we must remember that "one size does not fit all." Moreover, quick, effective, and vigorous actions have been lacking.

Of importance, there is a tendency to extrapolate from previous scientific approaches to pandemic management that did not factor in the variables of the evolution of human social, political, medical, economic, and financial changes over time. Lessons of pandemic management in the 19th and 20th centuries, for example, need to factor in the reality that the 21st century IHS framework is vastly different and, inherently, more complex – both for better and for worse. Also, in the last few decades, there has been a dramatic disinvestment in the area of public health and the concept that investment in the workforce's physical well being and mental health positively influences productivity has been either abandoned or significantly de-emphasized. Nevertheless, the immense costs for the global economy of the COVID-19 pandemic have changed this paradigm and forced all stakeholders to re-emphasize the need for robust and consistent public health funding. As a matter of fact, no other pandemic has affected the U.S. and the global economy with such historical precedent [29, 30], at least in absolute terms.

#### **8. Conclusion**

The expanded and redefined scope of International Health Security provides a unique opportunity for the public health community to embrace a more holistic approach toward an area that was traditionally much more narrow in scope [18]. Our current crisis reminds us, on a daily basis, how unprepared we continue to be for the events of a Public Health Emergency of International Concern (PHEIC) [23, 31–33]. As we tackle one of the greatest challenges to IHS in recent decades (if not of the past several centuries) – the novel coronavirus 2019 (COVID-19) pandemic – it becomes increasingly important to shift our focus to a more global, yet significantly more granular and scientific, perspective on IHS threats and emergencies. Such a perspective permits quicker, more effective, and more equitable responses for future PHEICs. We hope that the foundation created by this Editorial team will provide a solid springboard for an insightful and captivating discussion in this rapidly developing and important area of academic international medicine and public health.

*Introductory Chapter: International Health Security in the Era of COVID-19 DOI: http://dx.doi.org/10.5772/intechopen.98691*