1. Introduction
According to the Fifth Assessment Report (AR5) of Working Group (WG) I of the Intergovernmental Panel on Climate Change (IPCC), the observed climate changes attributed to human activity could be summarized as snow melting and reduced snow cover, permafrost thaw, air temperature increase, more frequent temperature extremes, droughts increase, frequency increase of intense precipitation, flooding, hurricanes, tornadoes, other extreme weather events, sea level rise, and more frequent wildfires [
1]. All these phenomena affect the mining sector in various ways.
Intense downpours seriously affect mine geomorphology and drainage, causing intense stability problems to mine benches, waste disposal areas, and tailing dams; overflow of ponds, dams, reservoirs, ditches, and culverts; loss of machinery and equipment; damages on haul roads and other transportations facilities; productivity loss; operations disruptions; and personnel risk injury [
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12]. On the contrary, reduced precipitation may exacerbate water-use pressures to water-intensive processes [
7,
13,
14,
15]. Temperature rise causes ice road melting, enormously increasing the transportation costs of arctic mines [
16,
17], whereas permafrost thaw may cause static problems to various mine site infrastructure foundations [
16,
18]. Temperature rise along with precipitation decrease adversely affect both hydroelectricity production and mine energy prices [
19] and wet tailings facilities, increasing water consumption in perpetuity [
20]. Furthermore, extended droughts negatively affect the water withdrawals of mining firms, while plants in rehabilitated areas increase irrigation needs and may cause frequent wildfires destroying past rehabilitations, ore seams, equipment, or assets [
19,
21]. Extreme winds and precipitation may cause the overtopping of toxic wastes and lead into mine discharges from tailing dams [
10,
20]. Extreme high temperatures negatively affect the mining industry globally by declining productivity and rational decision making and increasing personnel absenteeism and the risk of heat-related illnesses such as malaria [
13,
14,
19]. Extreme weather events (typhoons, floods, heat waves) may damage the vegetation cover of tailing dams [
20], as well as adversely affect electric power generation and transmission, causing a significant risk to mining companies [
19,
21]. Sea level rise may affect port facilities causing market and/or supply chain disruptions [
13,
19,
22,
23,
24,
25]. Nevertheless, the mining sector may be possibly benefited in some occasions from climate change, e.g., increased ambient temperatures and decreased snowfall in the Arctic or cold climates such as Greenland will allow prospecting, operations, and shipping (i.e., new ice-free channels) throughout the year [
13,
19,
26,
27,
28,
29]. Notable climate change-related incidents in the mining industry include: (i) the premature Winter Road closure, in Northwest Territories, Canada, in 2006 that resulted in an extra cost of
$11.25 million to Rio Tinto’s Diavik diamond mine and the bankruptcy of the Tahera Diamond Corporation, which operated the Jericho diamond mine [
16,
30]; (ii) the 2012 floods in Queensland, Australia, that hit 85% of region’s coal mines and created losses of more than 2.5 billion dollars [
31] and a significant drop to the country’s gross domestic product [
32]; (iii) the 2008 flooding incident to Ensham coal mine in Central Queensland, Australia, which provoked direct losses of more than AU
$300 million due to decreased production capacity and loss of sales (the company declared “force majeure”) [
10]; the 2011 incident at Rio Tinto’s operations, in Australia, that resulted in loss of earnings of
$245 million; and (v) the extreme rainfalls in Chile, in the first quarter of 2011, that suspended the production of Anglo American’s Collahuasi mine, the world’s third largest copper mine [
30]. Furthermore, a sizable amount of mining activities in countries such as Australia, Canada, Chile, China, South Africa, and the United States of America have increased impacts from climate change, according to 2019 Global Climate Risk Index [
33].
Despite the above-mentioned incidents, the current emphasis by the mining sector, so far, has been given to mitigation actions. There are several reasons and challenges behind this reaction. First, the strict Carbon Tax schemes negatively impact the company’s balance sheet. Second, the mitigation investments result not only in reduced greenhouse gas emissions, but also in cost savings due to efficiency improvements. Third, there is a major lack of knowledge across mining companies on the financial consequences of climate change and on adaptation indicators or other measures of adaptation effectiveness. This missing piece of information about climate change costs hinders proactive actions, and consequently the sector’s adaptation. Nelson et al. [
19] argued that there is a knowledge gap among the sector’s professionals related to the quantification of potential losses from climate risks. The authors suggest that apart from the physical risks of climate change, the mining industry should pursue a better understanding of the site-level social risks and opportunities, which is an action that will enhance its social license to operate. Acclimatise [
28] also stated that the sector needs to shift from extreme (acute) risk management activities to chronic (incremental) changes whose nature is more subtle and whose “impacts may pass undetected until critical thresholds are breached”. This management challenge would climate-proof the mining enterprises by incorporating current extremes with the trend of becoming tomorrow’s “business as usual”, thus being prepared for new higher extremes (adaptation process).
Empirical studies have shown that the mining sector has the ability to adapt within its environment in spite of past adverse historical events [
8]. Adaptive management (or governance) offers a new modus operandi for the sector in the face of climate change uncertainties that complements existing risk management measures already implemented in order to minimize climate risks [
34]. Landis et al. [
35] argued that adapting management actions and interventions in a changing environment can help address the factors that hinder effective assessment and managerial actions such as inaccurate scientific assumptions or initial poor process design. Acclimatise [
28] and ICF Marbek [
29] pointed out that there exist several opportunities for integrating climate risk management tools into existing mining corporate workflow and governance. Therefore, the major quest for the sector is the shift from day-to-day business and dealing with climate change in a reactive and fragmented way to a coherent, proactive, long-term adaptation planning.
All the above-described negative manifestations of climate change on the mining industry call for a prompt implementation of adaptation strategies [
7,
8,
9,
10,
11,
17,
18,
26,
32,
36,
37,
38,
39,
40,
41,
42] and the development of a practical tool for the assessment of climate change-related economic risks that the extractive companies are facing [
5,
43]. Specifically, the World Gold Council [
43] proposes, as a future area of work, the development of a tool to support the investment community in the context of climate change, provided that risk management is a very useful framework for supporting climate-related decision making [
12]. This tool should allow for the analysis of physical risks related to gold mining projects that are comparable with other sectors and asset classes. Furthermore, since major mining projects need external secure financing from institutional investors such as the International Finance Corporation, the European Bank for Reconstruction and Development, Barclay’s, and other players in the financial sector, a simple tool for highlighting and prioritizing the risks, vulnerabilities, and possible adaptation measures would be extremely useful for all the sectors involved (mining, insurance, and fiscal). This tool should have, in addition, the capability to address compounding and cascading events [
44,
45].
In this paper, we introduce an innovative climate change risk assessment framework for mining practitioners, which correlates risk with a mining company’s financial outcomes. To the authors’ knowledge, it is the first climate change risk assessment model for the mining sector that confronts all the relevant climate change-related hazards that could take place in a mining activity. Furthermore, the proposed framework provides the economic dimension of climate change impacts, can capture adverse as well beneficial effects of climate change in the mining sector, and is well suited for prioritizing potential adaptation strategies. The proposed model can use either qualitative or quantitative input, combining future climate projections data along with expert judgment, and incorporates fuzzy logic to address uncertainty in projected climate changes, as also recommended by the IPCC for policy planning. Our final aim is to establish a robust risk assessment methodology for the mining community that could serve as a decision-making tool for selecting and prioritizing among a range of adaptation actions when dealing with climate change.
The rest of the paper is structured as follows. The following section provides a cohesive literature review on existing methodologies related to climate change vulnerability and more precisely to climate change multi-risk assessment frameworks.
Section 3 details the proposed risk assessment framework for the mining industry.
Section 4 presents an illustrative example of the model in a hypothetical context. The paper concludes by stressing the advantages of the proposed methodology should it be incorporated in usual mining management practices and some thoughts for future work.
2. Current State of the Art in Climate Change Multi-Risk Assessments
Climate change risk identification, assessment, and evaluation formulate the backbone of risk analysis, which, iteratively, with scoping and implementation represent the necessary steps of managing the risk deriving from climate change [
12]. Hazard in the climate change context represents the physical phenomenon that might harm, cause damages or losses, or incur risk; generally, it represents the quantification of any possible negative consequences of any hazardous situation to any risk receptor. In the context of climate change, a climate risk represents the risk from one or more climate hazards. According to the number of hazards (single or multiple) and receptors (one or many) under consideration, the process of assessment could be called single or multi-hazard risk assessment for a single receptor and multi-risk assessment for multiple receptors [
46].
So far, a number of models and frameworks have been developed toward assessing climate change-related risks on natural and human systems, at the regional and local level. All these efforts are in accordance with guidelines issued on behalf of various international and European institutions such as International Standards Organization (ISO) [
47,
48], or national authorities [
49]. For instance, the “CLimate change and Urban Vulnerability in Africa” (CLUVA) framework offers a common way for presenting hazard assessments from multiple sources at regional and local levels, incorporating uncertainties and the assessment of proposed adaptation strategies [
50]. The “South East Europe Joint Disaster Management Risk Assessment and Preparedness in the Danube Macro-region” (SEERISK) project presents a framework for local level risk assessment, risk reduction strategies, and risk mapping, using an event tree analysis approach that could be used even in data scarcity situations [
51,
52]. The “European Spatial Planning Observation Network” (ESPON) project developed a participative multi-hazard approach for climate change vulnerability assessment and mapping on all European territories at regional and local levels [
53,
54,
55]. The project named “Advanced Terrestrial Ecosystem Assessment and Modelling” (ATEAM) developed a national and regional climate change vulnerability assessment, integrating several ecosystem models and climate change future emission scenarios across Europe [
56,
57].
The above-mentioned efforts examine all the relevant climate change hazards addressing the needs of many users across sectors. Yet, most of the published climate change-related studies either focus on selected hazards or narrow their range to targeted sectors or scientific communities. Among them, only a few studies focus on the mining sector, such as the study of Rayne et al. [
58], who developed a risk-based estimation of climate change effects on mine waste runoff water quality or the study of Chen et al. [
59], who created a spatial framework specifically for flooding risk assessment in Australian coal mines, combining several climatic, environmental, and hydrological data obtained from daily time-series observations. Similarly, Liu et al. [
60] developed a Geographic Information Systems (GIS)-based methodology for assessing flooding hazard and its impact on coal mines at the regional scale, using Bayesian network and remote sensing techniques.
Other European research initiatives focused on climate change impacts on infrastructures are: the study of Tsavdaroglou et al. [
61], who proposed a probabilistic methodology for risk analysis of interdependent critical infrastructures to extreme weather events and the “Risk Management for Roads in a Changing Climate” (RIMAROCC) framework [
62], which enables European national authorities to identify road network risks with the associated different action plans and assess the economic implications of each action taking into consideration implementation, maintenance, and environmental factors. Canadian authorities developed corresponding frameworks such as the Canadian public infrastructure risk assessment methodology named “Public Infrastructure Engineering Vulnerability Committee (PIEVC) Engineering Protocol for Infrastructure Vulnerability Assessment and Adaptation to a Changing Climate” [
63,
64] or the model of Etkin et al. [
65], which focused on the permafrost thawing impacts on engineering design and infrastructures. Kontogianni et al. [
24] developed a vulnerability framework focused on the implication of climate change to small harbors, taking into consideration geophysical and socioeconomic parameters. Jäger et al. [
66] developed a decision support system (DSS) for predicting onshore hazards and coastal impacts using evidence of past storm scenarios and known land use–vulnerability relationships such as damage curves. Finally, Zhou et al. [
67] introduced an integrated urban flood risk assessment framework that incorporates climate change impacts, inundation models, and adaptation options cost assessment.
Gallina et al. [
46] performed an extensive review of multi-hazard, multi-hazard risk, and multi-risk methodologies used in the context of climate change. They argue that the long-term effects of climate change have not been adequately integrated (most methodologies focused on multi-hazard assessment without considering changes in space or time). The authors propose that for climate change risk assessments, one should integrate qualitative (with expert opinions, as well as stakeholder and participatory involvement) and quantitative methods (e.g., climate modeling, statistic handling of uncertainties, and GIS).
The review on the state-of-the-art research on climate change risk assessments revealed a number of frameworks that examine risk and vulnerability notions across diverse contexts and scales (i.e., in relation to climate change, natural and man-made hazards, disaster loss reduction, and at the national, regional, or local level). Well-developed multi-risk frameworks (such as SEERISK) and multi-hazard risk ones (such as ESPON) belong to a series of research initiatives funded by European Commission (EC) involving universities, academia, research centers, organizations, and scientists mainly in Europe. Irrespective of their origin, though, very few frameworks attempt a deterministic quantification of examined impacts, and more precisely, the research effort of Tsavdaroglou et al. [
60]. Nevertheless, these frameworks neglect to quantify and to incorporate in their economic output the various uncertainties either from climate projections or from missing data. Furthermore, to the best of our knowledge, there is no existing framework developed for financial institutions of any size that examines climate change risks in a multi-hazard or multi-risk level, taking into consideration the total estimated financial risk of climate change and correlating it with the viability of the impacted institution. A few studies propose a flexible framework for either qualitative or quantitative assessments dependent on the available data, such as RIMAROCC. Finally, a few frameworks incorporate and prioritize adaptation strategies (such as CLUVA and RIMAROCC). Even fewer explicitly deal with uncertainty and fuzziness such as CLUVA and RIMAROCC, as most climate change risk assessments are based on deterministic models. In relation to the mining sector, scientific efforts have focused on climate change single-hazard risk assessments (mainly mine flooding mishaps). Eventually, linking to the aim of the present study, there is a lack of a comprehensive framework that could assess climate change-related risks for all the subcomponents of the mining industry at a mine-site (i.e., local) level. Ideally, a proposed framework should combine future scenario-driven (top–down) approaches at the local level with vulnerability-driven approaches for addressing long-term vulnerability and the assessment of pre-emptive adaptation responses [
68].
4. Illustrative Example
The proposed climate change risk assessment framework is implemented by a team of professionals ideally made up by climate, geotechnical, hydrogeology, and mining experts, and builds on their knowledge, values, and experience [
68,
129]. Given that the multidisciplinary expert team uses the proposed CLIRMI framework on behalf of and for the benefit of the mining corporation under analysis, it follows that it is for the corporation’s best interest that the necessary expertise and the most appropriate range of scientific specializations is assured according to the performed operations. Therefore, scientific specialization with hands-on experience on the fields of climatology/meteorology, geology, hydrology, coastal erosion (for coastal activities), etc. are definitely mandatory. In environmental modeling, often parameter estimation is achieved using experts’ subjective knowledge. The goal of this multidisciplinary process is to arrive at an agreed compilation of the necessary inputs for the model through documented, informed judgments, the use of directly relevant knowledge (environmental, scientific, engineering, operational, or local), and a sharing of collective views [
64,
68,
129]. Examples of such procedures are already part of the mining industry decision-making process [
101] and EC-funded projects for climate change adaptation research.
Hereinafter, an illustrative example of the CLIRMI framework is presented using a hypothetical case study. The theoretical CLIRMI mine is an industrial minerals mining company located in a small island named Virtualislet. Virtualislet has a total surface of 100,000 km2 and mild relief; its tallest mountain is below 400 m. CLIRMI mine operates at the center of the island, and is a 50-ha open pit bentonite quarry where only mechanical extraction and loading is performed without any size reduction due to material properties. However, numerous—more than 30 so far—mine benches are stable due to the coherent deposit and absence of geologic soil faults. Extracted material (around 90 ktpa) is loaded to haul trucks and transported to open-air storage areas. Then, the run-of-mine (ROM) material once again is loaded to haul trucks and transported to the port facility where with the use of mobile mechanical equipment (loaders, feeders, and conveyor belts) is finally led to mid-capacity bulk carrier vessels on a monthly basis. CLIRMI mine has an annual gross revenue of around five million euros, a total unit cost of 45€/tn, and an average sale price of 55€/tn, permitting an annual gross profit of 900,000 Euros.
The above-described theoretical mining activity is assumed to be impacted by the following climate-related hazards: flooding of the mine, haul road damages with transportation disruptions, and increases in product waste during intense downpours. Further, extreme winds and storm surge negatively affect port facilities and delay ship loadings. Finally, heat waves affect working conditions, during which production ceases with a subsequent loss of production and transportation decline. Therefore, the following three hazards are considered: (i) flooding, (ii) extreme winds or storm surges, and (iii) heat waves. These hazards affect both ore extraction and product transportation mine subsystems. Each of these hazards, as discussed in the
Section 3.3.3 titled “
Triggering Climatic Events”, are associated with certain TCEs. The team of professionals after reviewing historic climate data, mine adverse climatic manifestations, impacts, and local factors defined that for the described hazards, the associated TCEs are: (i) daily rainfall above the 40-mm threshold; (ii) wind gust speed above 10.8 m/s; and (iii) daily maximum temperature above the temperature threshold of 38 °C.
According to the A1B IPCC climate scenario, for the mid-21
st century period, for the imaginary region and in relation to the historic period between 1961–1990, there seems to be a 135% increase of rainfall events above the 40-mm threshold, a 1.6% increase of wind gust speeds greater than 10.8 m/s, and a 115.7% increase of days with T
max above the 38 °C threshold. After reviewing these projections, the experts estimate the annual likelihood probability for each of the three TCEs causing the hazards under consideration. The projected rainfall increase means that for the future 30-year period of the analysis, rainfall events above the 40-mm threshold are estimated to occur 14 times in total. Therefore, the annual likelihood probability of such rainfall events, i.e., 46%, is expressed as a combination of the discrete classes of
Table 3, namely 80% likely and 20% probable. Furthermore, extreme winds and heat waves are estimated to occur, annually, seven and 12 times, respectively, making both events 100% remarkably probable (
Table 5). Then, assuming that each hazard does occur, the experts estimate the economic impact per incident on every mining subsystem in two different forms: as a percentage of annual revenues and as net monetary losses in a probabilistic form, i.e., the minimum, average, and maximum expected amount of money (
Table 6 and
Table 7, respectively). It is noted that for the solution of the discrete BBN, the data of
Table 5 and
Table 6 are used, whereas for the CLGN model, the data of
Table 5 and
Table 7 are used.
The results of the discrete BBN (
Figure 3), which are presented in
Table 8, show that there is a 58% chance for 2–4% annual revenue losses, a 41% chance for 4–5% annual revenue loss, and a remaining 1% chance for even more hazardous losses (i.e., between 5–10% of annual revenues). Given the above-estimated probabilities and the annual turnover of the mine (i.e., €5 million), the annual losses range from €142,500 to €223,500.
Using the CLGN model, the economic losses are estimated, in a more straightforward, i.e., quantitative, way. In this case, the severity nodes are continuous functions following the triangular distributions of
Table 7.
Figure 4 illustrates the overall CLGN model and presents the distribution of the total economic losses as well as those of the “ore extraction risk” and “transportation risk” nodes. Based on experts’ assumptions, the mean annual loss calculated by the CLGN model is about €178,000 (standard deviation ≈ €22,000).
In order to illustrate how the CLIRMI framework could assist mine operators in climate adaptation decision-making processes, it is assumed that CLIRMI mine managers examine two distinct adaptation options: (a) mine site drainage to reduce flood risks and (b) loading facilities strengthening to reduce the impact of extreme winds to transportation. Mine site drainage adaptation works comprise of a procurement of a new drainage pump and the construction of several kilometers of levees banks that are capable of prevent flooding events even under extreme rainfall of 200 mm per day. The implementation of these adaptation works would eliminate the occurrence of flooding events from 14 to less than two in the next 30 years (i.e., the annual likelihood probability decreases from 0.46 to 0.06). The total cost of these works is €500,000. The loading facilities strengthening option has an investment cost of €1.5 m and consists of upgrading the existing port facilities in order to maintain safe berth status during wind gust speeds of 12 m/s. As a result, the loading disturbances would be reduced from seven per year to four per decade (i.e., the new annual likelihood for the anticipated hazard becomes 0.4). The new annual probabilities for the hazards under consideration are presented in
Table 9, and the results for the discrete and the hybrid models, with and without the adaptation measures are given in
Table 8 and
Table 10, respectively.
The annual adaptation benefits from the mine site drainage and from the improvement of port facilities are equal to €67,000 and €88,000, respectively. The equivalent annual cost (EAC) for the adaptation actions, assuming a cost of capital equal to 10% and a lifespan of 30 years, is estimated to €53,000 for the mine site drainage and to €159,000 for the port facilities, using the following equation:
where:
r is the cost of capital,
n is the lifespan (i.e., 30 years), and
I is the investment cost of the adaptation action
In the case of flood risks, the annual benefits (i.e., the reduction in economic losses achieved through adaptation) exceed the annual costs of adaptation and, thus, the adaptation investment is annual savings. On the contrary, the investment in the strengthening of port facilities is not justified, since the annual adaptation cost is higher than the benefits gained by the proposed adaptation action.
5. Conclusions
For several decades, the scientific community made significant progress in various directions of climate change vulnerability analysis, creating alarm about the necessity of climate change mitigation and the incorporation of adaptation strategies in daily operations. Several institutional stakeholders have noted the need to transcend from the vague and obscure vulnerability assessments to a more practical, manageable, and understandable framework for climate change risk assessments such as the one introduced here [
42,
130,
131,
132,
133].
In the present paper, a new framework for the multi-risk assessment of acute climate change-related hazards that occur in the mining sector is introduced. The proposed framework, contrary to other scientific efforts, includes all the relevant extreme events that affect the mining industry permitting the assessment of multiple risks, compounding, and cascading events [
44], using a probabilistic model. Our framework follows a bottom–up, vulnerability-based approach [
130], based on local knowledge and the expertise of a multi-disciplinary team of experts. As noted by Smit and Wandel [
134], this type of participatory vulnerability approach, which induces stakeholders’ participation and involvement in all stages, identifies feasible and practical adaptation strategies. Moreover, this type of assessment is perfectly suitable for examining cases with a paucity of data either climatic or corporate.
The model has open-architecture; it is modular, scalable, and can be adjusted to the user needs (i.e., it can be more analytic if the company can provide more detailed data). The proposed risk assessment framework is based on risk analysis, which is a practice that is quite familiar for most mining managers and practitioners, as it is a well-established method in their everyday routine. The main advantage of the model is that it quantifies climate change risks posed to the mining industry in monetary terms through two alternative ways: either as a percentage of annual revenues or as net value. Hence, one of the most useful aspects of the model is the intuitive way of expressing risk in an easily communicable format. In this way, it is our hope that the model can be seen as a useful tool for the mining sector’s managers and practitioners for everyday decision making. Nevertheless, it is noted that the proposed framework has also certain limitations. The model is based on expert judgment for the quantification of adverse climate change consequences, which means that: (a) it is prone to cognitive and motivational biases that can occur when eliciting inputs from experts, and (b) the selection of suitable members for the team of experts is extremely crucial for the obtained results. Furthermore, the model does not take into consideration slow onset events such as, for example, sea level rise or permafrost thaw. In some cases, the cost of slow onset events may prove to be high; therefore, future research efforts should shed light on this aspect as well. Further research is needed to fill the gap resulting from the scarcity of past climate change-related costs in the mining sector. Moreover, the proposed model, although originally developed for mining infrastructure, could relatively easily be adapted to other infrastructures in energy, road, railway, etc. Finally, a future improvement of the model is the development of a web-based decision support system. This could help disseminate, use, test, and validate the proposed methodology and facilitate climate-related decision making processes in the mining sector and elsewhere.