The Intergovernmental Panel on Climate Change (IPCC) is a body of the United Nations responsible for assessing climate change, its impacts, and future risks. It is currently in its sixth assessment cycle, referred to as Assessment Report (AR6). During this assessment cycle, the IPCC has noted that each of the last four decades has been successively warmer than any decade that preceded it since 1850 and that there has been an increase in global average rainfall since 1950.
Outputs from the global circulation models (GCM) provided by the IPCC include time series of key climate parameters from 2011 through 2100. While the AR6 provides regional interpretation of GCMs to inform projects and planning, more site-specific information is required. Dissecting critical information from these large datasets, such as understanding future extreme precipitation statistics or the frequency and severity of drought conditions, can be onerous but can be fast-tracked using data science tools and programmes.
With an extensive amount of potential climate scenarios, incorporating different socio-economic conditions, greenhouse gas (GHG) emission pathways and pooling from different model developers, the critical task lies in normalising each dataset with respect to its associated baseline condition. SRK recommends looking at the rate of change from the future periods over each baseline period instead of relying solely on the GCM values in the projection timeframe. The range of results from all individual GCMs and each emissions pathway are then reviewed, since no specific model output is more correct or likely than another. This data can be presented in terms of exceedance probabilities or a statistical distribution, so users can understand the model agreement between scenarios, as well as the outliers in potential extreme conditions.
Taking a risk-based approach to site-specific climate assessments
Decision-makers must then take a risk-based approach to select which climate change conditions should be applied to the site in question. For high-risk infrastructure, a more conservative climate change model output would be appropriate, for instance. Alternatively, infrastructure can be tested under a range of conditions including combinations of different extremes. This builds an understanding of the resilience of individual components to a changing climate, as well as the flexibility of the system as a whole.
The climate inputs that influence mining infrastructure and operations are typically specific design criteria, like the one in 100-year rainfall depth or the mean annual precipitation depth. These inputs are relatively straight-forward to analyse using the GCM outputs and applying the same statistical analyses to the GCM time series data as we would apply to historical climate data. However, some physical risks from climate change are harder to quantify, such as droughts, heat waves, and forest fires. To understand how climate change could affect these types of conditions, SRK looks to standard climate indices, like those reported by Climdex, to examine the change relative to existing conditions. Droughts, for example, could be evaluated by looking at an indicator such as the number of consecutive dry days. The change in this index from historical conditions to different future climate conditions could indicate if periods without rain are expected to increase and to what extent. Similarly, the GCM data can be used to calculate the warm spell duration index. This index may be used to indicate the change in occurrence and severity of heat waves.
Building climate resilience starts with understanding the risks, which requires mining decision-makers to understand the full range in future climate conditions. Having tools available to quantify useful climate indicators and relate these indicators back to operations and performance will be a critical step for the mining industry in being prepared for the future.
Building resilience to climate change
Once the risks are understood, it is important to build resilience to these changes. Climate change poses a serious immediate risk to water resource quality and quantity. Drought, floods, and other water-related risks have in recent years threatened the sustainability of businesses, demanding a strategic and systemic approach to their water needs and sources. Many of the systemic water risks facing businesses cannot be adequately solved through company operational measures. An effective response to these risks therefore involves the concept of water stewardship, a process whereby organisations work collaboratively with other partners to manage shared water resources.
The Alliance for Water Stewardship defines water stewardship as “the use of water in ways that are socially equitable, environmentally sustainable, and economically beneficial” (Ref: Alliance for Water Stewardship).
Water stewardship considers the fundamental aspects of water including water governance (responsible and accountable water); water balance (water quantities and timing); water quality (purposes of water); location and spatial extent of water sources, water use, and discharge; and identification of important water related areas (human and ecological beneficial areas) as well as safe water, sanitation, and hygiene. All these components are strongly linked to the principals of environmental and social governance and the sustainable development goals.
The adoption of a water stewardship programme for an organisation helps to build resilience into operations in relation to water use and discharge. Therefore, water stewardship provides a mechanism to contextualise a site within a catchment, encourage appropriate water use management, and water resources impact mitigation.
Part of a water stewardship programme may include the consideration of sustainable drainage systems (SuDS). SuDS use ecosystem goods and services to replace traditional engineering. These systems are often more resilient to change, have reduced operational costs, and/or offer amenity and green spaces but do require more space for implementation. A typical example of using SuDS is the creation of a constructed wetland as an alternative approach to dealing with attenuation of storm flows. In addition to offering attenuation, it creates a natural, aesthetic solution to water quality improvement.
Bottom line: adaptability is key
While models offer predictions to inform planning, as highlighted above, the number of potential climate scenarios coupled with the inherent uncertainty of a changing climate means adaptability will be key.
Water stewardship offers opportunities to build resilience and adaptability at a catchment level, while SuDs offers adaptable ecosystem-based solutions. However, there remains a need for ongoing monitoring and flexibility to react to observed monitoring trends. This is particularly critical for physical risks from climate change that are harder to quantify using model outputs.
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