Declining lake ice in response to climate change can impact spending for local communities

differences in the outcomes of lake ice based on the projected greenhouse gas emission scenar- ios (Fig 2). For high latitude countries, the differences between RCP scenarios translate to 10, 100, or even 1000 times more area of ice being lost. The burdens of climate change are typically associated with countries with lower GDPs, and also those that currently emit the least green- house gas emissions, making these countries least able to mitigate future negative impacts [76, 77]. However, lake ice represents one of the few instances where the countries impacted by cli- mate change are the most capable of mitigating change. Since it is the countries with the high- est emissions that have the most to lose (Fig 3), our findings should therefore further encourage action to mitigate emissions. Limitations While modelling studies are powerful, allowing the synthesis of patterns at a global scale, we recognize there are some limitations in our methodology. Firstly, we used gridded simulations that are averaged patterns over 0.5˚ longitude-latitude grids where individual lakes will likely deviate either more or less in duration. This is further complicated by the limited availability of examples of lake ice revenue, restricting a comprehensive analysis of consequences from dif- ferent activities or geographic regions. The ISIMIP models also do not provide any informa- tion on snow, which is an important factor influencing ice dynamics and may impact lake ice activities. Finally, our study is based on stacked uncertainty, where the uncertainty in climate

models, compounded by the dependence of lake models on these climate models, reduces the confidence in predictability. We discuss this stacked uncertainty and the interaction with dis- count rates in our S1 File. Our study represents an initial step to estimate the financial impacts of lake ice loss in a global context, but these limitations underscore the need for future research to better refine and accurately quantify these complex dynamics. Conclusions Our findings further illustrate the complex and substantial costs of climate change that lend sup- port for mitigation being less costly than the impacts [e.g., 6, 7]. The anecdotes presented in this paper describe a suite of activities that occur in a band of latitudes across the globe that provide social, cultural, and financial value. With shrinking lake ice, these activities will be relocated northward, turned into other activities (i.e., open water activities), or lost entirely. We acknowl- edge there is a great amount of uncertainty in this type of exercise around the estimates of ice phenology [78], forecasting inflation/depreciation (for a discussion, see S1 File), and generalizing globally. Our study provides the first efforts to quantify the expected changes in spending from declining lake ice. More importantly, within the wide bands of uncertainty, we can undeniably state that spending habits for many communities previously dependent on lake ice will be chang- ing in the coming decades. We estimated a difference of 10% and 33% in lake ice duration

between the high and low greenhouse gas emissions scenarios, suggesting a large benefit to take climate action just in lake ice alone. Additionally, if action to mitigate climate change continues to be delayed, the cost of mitigation will continue to rise or cause the greenhouse concentration limit of RCP 2.6 and 6.0 to become untenable [79]. Critically, climate change effects on lake ice will largely be felt by the economies of countries most capable of enacting change to mitigate the impacts. Continued efforts to quantify the economic implications will be crucial throughout the 21st century as countries expand efforts to both mitigate and adapt to climate change. Supporting information S1 Table. Examples of spending from lake ice activities in local communities. (PDF) PLOS ONE Financial loss of declining lake ice PLOS ONE | https://doi.org/10.1371/journal.pone.0299937 July 5, 2024 10 / 15