Climate models

Which areas will climate change make uninhabitable? Climate models alone cannot tell


Which areas will climate change make uninhabitable? Climate models alone cannot tell

by Radley Horton and Alex de Sherbinin
|June 17, 2021

This Somali family left their village after a drought killed most of their livestock. As climate change exacerbates droughts and food shortages in some areas, many people may be forced to leave their homes. But the decision to migrate or not depends on many factors that cannot be captured in a climate model. Photo: Oxfam East Africa

Scientists often rely on global climate models and high-level data to anticipate which regions of the world will face floods, droughts and other hardships in the future. We use these models to communicate the urgency of climate change and to give a general idea of ​​areas that are likely to be high risk “hot spots” and therefore potentially uninhabitable in the future. Yet, as we learned during the Managed Retreat 2019 conference at the Earth Institute at Columbia University, this approach is not always well received by at-risk communities. Top-down modeling approaches can contribute to climate determinism that minimizes the potential for human ingenuity to find creative and locally appropriate solutions. Prioritizing likely future climate impacts may also seem deaf in communities that have experienced racist and land grabs.

In a new commentary in Science, we argue that ‘top-down’ approaches typical of climate modelers should be combined with ‘bottom-up’ approaches that involve communities, collect local data and assess solutions. This combined strategy is key to helping communities build resilience and adapt to climate change, and will be part of the discussion at the upcoming Managed Retreat conference June 22-25, which we helped organize.

The “top-down” approach has its merits. It is relatively easy to use multiple model runs to produce global or regional maps that convey important information about the distribution and severity of threats. These models also allow comparisons between different areas and can reveal large-scale trends and interconnected features of global systems. However, their broader scope overlooks the factors that drive risks at the local scale and leaves out the characteristics of local populations – such as health, socioeconomic status, historical background and culture – that can shape the exposure and vulnerability.

For example, it is possible to combine projections of sea level rise with models of rise to estimate that coastal flooding is likely to affect between 310 and 630 million people worldwide by 2100. Yet threats to infrastructure and the risk of sea level contaminating wells with salt water depend on other factors, such as local geography. Additionally, different communities vary in ease of evacuation, access to flood control measures, and exposure to coastal storms. Factors such as levels of inequity, the strength of governance and social networks, and the quality of infrastructure will also be critical in determining whether specific areas remain viable. Thus, top-down methods cannot define a single coastal flood threshold that applies to each community.

By definition, bottom-up assessments provide more detailed data. These methods can engage a variety of stakeholders to generate qualitative data and explore high impact scenarios and local solutions that would be missed by top-down approaches. These approaches can account for how people respond behaviorally to changing environmental conditions – loss of assets and livelihoods, changes in insurance premiums, threats to life and the changing structure of social media. . In fact, such societal tipping points could be better predictors of community withdrawal than the results of top-down geophysical modeling. Engaging the community also empowers them to take action, rather than projecting a sense of inevitability and hopelessness that can make individuals reluctant to work together or with local authorities to reduce risk and build resilience.

However, to date, most localities have not been subject to such an integrated livability assessment. In addition, the specificity of bottom-up methods makes it difficult to compare geographic areas and groups, and to apply lessons and solutions from one area to another.

The solution is to meet in the middle – creating a holistic, people-centered approach that integrates models, data aggregation and ethnographic work. We should use top-down habitability assessments to identify groups and regions that should be prioritized for bottom-up work. For reasons of climate justice, many semi-arid regions, much of the tropics, and some low-lying deltas and islands should be high priorities for this combined approach, as many of the most vulnerable populations are those most at risk. fewer resources to deal with climate change, and which have contributed the least to greenhouse gas emissions.

We need to develop policies that identify the most feasible local adaptation options in various geographies and groups, rather than deterministic and universal options. Such a mid-level strategy also avoids hyper-local solutions that cannot be applied in other communities, the development of which can be costly and time-consuming.

Some organizations, such as the Consortium for Climate Risk in the Urban Northeast, part of NOAA’s Integrated Regional Science and Assessment Program, are already working to bridge the gap between top-down research and community-based initiatives. The organization works by framing research around the needs expressed by communities through long-term deliberative engagement and cogeneration of knowledge. The Intergovernmental Panel on Climate Change (IPCC), national efforts, and institutions such as the newly developed Columbia Climate School can also provide the innovative and transdisciplinary approaches needed to further develop this promising middle space between top-down approaches. and ascending. .

Only by joining these approaches can we avoid climate determinism and hopelessness, and instead implement proactive policies on adaptation and migration that will reduce the damage caused by climate change and save people. lives.

From June 22 to 25, the Managed Retreat conference hosted by Columbia Climate School and the Earth Institute will bring together academics and community members to discuss relocating communities away from increasing climate risks. Buy your tickets here.