New Delhi, Oct. 24 -- We discussed the Nepal floods and the Broad Peak tragedy in the Karakoram range in the last two articles. In this article, we will analyse these events in the context of the economic and climate models discussed earlier in this series. We will also put forward possible solutions and suggestions.
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We may recall that General Circulation Models (GCMs) and Earth System Models (ESMs) divide the Earth into grids of 100 km by 100 km. Since these are large areas, each mountain peak cannot be 'seen' by the models. To factor in mountains, these models resort to parameterisation, basically using the laws of physics to approximate mountain climates. Similarly, in GCMs, glaciers are represented as fixed, non-moving 'white paint', which reflects everything. ESMs are more sophisticated and use ice sheet models. Hence, mountains and glaciers are not adequately represented in these models, and complex climate processes, such as shifting ice sheets or glacial lake formation, get left out.
We may recall that economists have used Integrated Assessment Models to arrive at a set of policies in various sectors. William Nordhaus and Nicholas Stern used Dynamic Integrated Model of Climate and the Economy (DICE) models to prescribe the need for mitigation and adaptation policies. The difference between them was that Nordhaus used a higher discount rate (4.3 per cent compared to Stern's 1.4 per cent) and modelled risk differently from Stern. This led to dramatically different policy prescriptions: while Nordhaus advocated a gradual approach, with emissions reductions rising over time (referred to as the climate ramp), Stern advocated an urgent approach, with emissions reductions beginning immediately. In other words, Stern valued the future far more than Nordhaus and emphasised intergenerational equity, with an immediate call to action to protect the environment for future generations.
Another important contribution was that of Martin Weitzman. According to Weitzman, neither Nordhaus nor Stern was looking at the climate change problem in the way needed today. Rather than arguing about discount rates, the focus should be on worst-case scenarios and the 'fat-tailed' nature of climate events. He proposed the 'Dismal Theorem', wherein one should not simply look at investments to mitigate the adverse effects of climate change but also plan for worst-case scenarios (such as warming of 6 degrees Celsius). Weitzman's prescription was in response to the dire warnings being issued by climate scientists that we are nearing tipping points, such as the thawing of permafrost and the melting of ice sheets, which are giving rise to extreme climate events, including massive flooding and landslides on an unprecedented scale.
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From the perspective of climate science, regional climate models are better suited to incorporating mountains and glaciers. These regional models have smaller grids of 10 km by 10 km and use high-resolution images of mountains and glaciers. This is called dynamic downscaling. Similarly, scientists examine actual recorded data from a mountainous area, compare it with model projections and then make corrections accordingly. This is known as statistical downscaling.
However, applying data from scientists' climate models and economists' models to policymaking requires greater interaction between the two disciplines. While some decisions, such as changing building codes and making infrastructure more climate-resilient, are relatively straightforward, others require finer adjustments based on carbon pricing or the pace of intervention (depending on the discount rate). From the discussions in Parts I and II of the articles on mountains and glaciers, it appears that Weitzman's approach to planning is what is needed. This is because 'fat-tailed' events are becoming more frequent, as we saw from the Broad Peak tragedy and the multiple glacial breaches in India and Nepal (Chamoli in 2021, Sikkim in 2023 and Nepal in 2026).
In fact, we have to go beyond Weitzman because there is a new normal involving cascading and compounding risks. A term being used for these events is 'tipping cascades', where one tipping point triggers another, leading to a devastating cascade. What makes matters worse is that there is no reliable way to monitor all such glacial outburst events or provide timely early warnings, even though monitoring of glacial lakes has increased.
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The rising frequency of devastating floods resulting from changing glacial structures is an unprecedented challenge. The policy response must be immediate, involving increased monitoring and more prudent planning of large projects in fragile alpine ecosystems. Worst-case scenarios must be identified, and provisions for insurance and preparedness must be made. These could include mapping vulnerable areas, improving relief and rescue preparedness, developing localised power grids, storing food and water in vulnerable areas, and strengthening municipal infrastructure, including sewage, drainage and water supply systems.
Even from a broader perspective, we must move beyond the traditional mitigation and adaptation framework and adopt a 'tipping cascade' framework, at least in the most vulnerable areas.
Published by HT Digital Content Services with permission from Millennium Post.