Scenarios and Uncertainty
Imagining different futures could be the perfect approach to think through options after we don’t know the percentages.
In environmental law, we’re often operating at the bounds of information concerning the natural world and human behavior. Climate change is well understood in some ways, but it’ll set off a sequence of reactions that we only partly understand. It’s also difficult to predict the long run of ecosystems, future energy prices, technological changes, and a number of other aspects relevant to environmental law. Scenarios could be the perfect approach to take into consideration making selections within the face of all this uncertainty.
Scenario evaluation avoids the pitfall of projecting a single probable future when vastly different outcomes are possible; broadens knowledge by requiring more holistic projections; forces planners to think about changes inside society in addition to outside circumstances; and, equally importantly, forces decision-makers to make use of their imaginations, while providing a check on the realism of the resulting stories.
Storylines are alternative pathways that allow us examine futures. They’ve been used as a part of scenario within the environmental area but much more commonly in mapping out international, business, and military strategies. Best practices for constructing scenarios have also emerged, including participation by individuals with diverse perspectives, independently obtaining expert input, using alternate assumptions to take a look at data, and using quantitative techniques to extrapolate trends. Rigorous evaluation based on expert opinions, data and modeling, distinguishes storylines from science fiction.
Inside the scenario family, nonetheless, are several different subtypes, various in the method for developing the scenario, whether the scenario is exploratory or designed to exemplify the pathway to a given final result (equivalent to achieving the Paris Agreements goals), or informal versus probabilistic.
Use of scenarios within the context of climate change has been a specific subject of attention.. The IPCC has developed one set of scenarios (the SSP scenarios for future pathways of societal development. Roughly speaking, these scenarios differ in the quantity of international cooperation and whether society is stressing economic growth or environmental sustainability. The SSP scenarios include detailed assumptions about population, health, education, economic growth, inequality and other aspects. A distinct set of scenarios, the RCPs, are used to model climate impacts based on different future trajectories of GHG concentrations.
Thus, the RCPs give attention to how emission trajectories shape warming, while the SSPs explore different pathways of world development as they’d proceed without climate policies or impacts. Integrated models are then used to mix the socioeconomic storylines, emissions trajectories, and climate impacts right into a single simulation.[ One significant finding is that just some scenarios are compatible with achieving the Paris Agreement’s aim of keeping warming to 1.5°C.
One advantage of the IPCC approach is that it provides standardized scenarios that could be utilized by many researchers taking a look at many various points of climate change. That’s an concept that agencies like EPA might emulate.
There appears to be nobody “right” approach to construct scenarios. Crucial thing in practice could also be for the agency to elucidate the choices and the explanations for selecting one approach over the others. It may also be useful for agencies to standardize their scenarios where possible, which might create economies of scale in scenario development, allowing comparison of results across different regulations, and supply focal points for researchers.
Scenario planning isn’t used nearly as much appropriately by agencies. Perhaps they’re afraid to confess that they’re uncertain about future outcomes of their actions. But we do, in spite of everything, live in an uncertain world.