Thread by @dwallacewells

"Managed retreat. Facilitated migration. Climate-related displacement." So begins a special issue of Science devoted to "climate-induced relocation." A thread of its contents, findings, and assertions... (1/x) science.sciencemag.org/content/372/65…

"Globally, sea level rise alone could place 340 million people on land projected to be below annual flood levels by 2050."

"The need for relocation will increase because of such risks, the lack of funding for protection and accommodation strategies, and/or the reality that sea walls and other measures will eventually be ineffective."

"Thus, current approaches to planned relocation such as buyouts for individual households are likely to be 'woefully inadequate' in the future."

"Planned relocation is a complex social dilemma that involves many structural, perceptual, economic, and interpersonal dynamics that discourage collective action."

"It will involve resolving fraught questions such as what decision processes are used, who relocates (and when), how are they compensated, where will they move, what assistance is provided (and to whom) in receiving communities..."

"...how abandoned wastes and environmental legacies are remediated, and how agreements are monitored and enforced."

"There is no single best approach to move a community—stakeholders with conflicting objectives will see it differently even when they share basic world views."

"The interaction of social and environmental triggers and lack of a preferred pathway make planned retreat similar to other global dilemmas. But the potential scope, existential character of transformations, and complexity of governance challenges make it especially demanding."

This is from @RichardHMoss et al, "Pluralistic and Integrated Science and Governance."

Next is "Assessing human habitability and migration," by @radleyhorton et al.

"Under the high-emissions scenario RCP8.5, at most coastal locations extreme sea level events historically defined as 1-in-100-year events are projected to range in frequency from once per year to more than 10 times per year due to the effects of sea level rise alone."

"In terms of the livelihood dimension, at ∼3.5°C of warming , de Lima et al. project that in Sub-Saharan Africa and Southeast Asia increases in humid heat may decrease agricultural labor productivity by 30 to 50%."

"The relationship between habitability and migration may be counterintuitive, as illustrated by the lack of evidence for migration away from low-lying delta areas despite acute risk."

"The shortcomings of adaptation planning and policy at current risk levels in wealthy countries hint at the global challenges ahead. In the U.S., for example, federal and local risk assessments—let alone policies—are not presently centrally coordinated or comparable."

"There is woefully insufficient funding available for bottom-up adaptation efforts from the better-financed federal level. Policies toward population mobilityvary from inconsistent over time to incoherent and sometimes inhumane."

"What is already clear is that climate change will result in shifting population distributions and that this process will overall be harmful to the most vulnerable, including those who may be 'trapped' in deteriorating circumstances."

"For the reasons described here, and as a matter of climate justice, many semi-arid regions, much of the tropics, and some low-lying deltas and islands should be high priorities for integrated transdisciplinary work on habitability risks and major investments in adaptation."

From @bdidmc et al, "Addressing the human cost in a changing climate": "Millions of disaster displacements have been systematically recorded since 2008—on average, 24.5 million new movements every year. Weather-related hazards account for almost 90% of all these displacements."

"Climate change is a displacement trigger in its own right (e.g., loss of coastlines), a visible aggravator (e.g., when livelihoods are eroded because of soil degradation), and a hidden aggravator (e.g., increasing the intensity of cyclonic winds and shifting rainfall patterns)."

"In Bangladesh, a disaster with a return period of 50 years can be expected to incur costs related to internal displacement of nearly U$4.1bn per year of subsequent displacement; a more frequent disaster with a return period of 10 years would incur more than US$1 billion."

"The estimated possible amount of funding that the country may be able to divert adds up to just over US$1 billion of fiscal resilience, which means that Bangladesh is likely to be unable to cover costs associated with internal displacement for events that occur every 10 years."

From "Pathways to coastal retreat," @Lijnonline et al: "Observed coastal flooding is already reaching unacceptable levels for communities and infrastructure in many low-lying coastal settlements around the world..."

"...and unless adaptation starts now, in a few generations, more regions (e.g., small islands, parts of the US coast, major deltas) will be at risk of coastal flooding. Additionally, retreat requires decadal lead time to plan and implement equitably."

"Because implementing managed retreat can take decades, it needs to be considered well ahead of any climate-induced societal and physical thresholds."

"The time needed depends on each society's willingness and ability to anticipate the climate risks and to act on them before observed impacts. Time is also needed to plan and engage with those affected about the urgency to start the retreat process now..."

"...so that individuals can make relocation decisions as opportunities arise."

"For example, in the Netherlands and New Zealand, retreat was signaled well ahead of project implementation in anticipation of the effects of climate change, which gave time (25 and 10 years) for eventual removal of houses and purchase of at-risk properties on a voluntary basis."

"This contrasts with instances where retreat has been triggered after damaging climate events (e.g., after hurricanes Sandy in New York and Katrina in New Orleans; where protection proved ineffective and retreat was forced, creating additional community stress and costs."

"Whatever the context considered, it is increasingly evident that the shrinking solution space for adaptation in low-lying coastal areas calls for long-term dynamic pathways planning now."

From "High-density population and displacement in Bangladesh," Mizan R. Khan et al: "4.1 million people were displaced as a result of climate disasters in 2019, 13.3 million could be displaced by climate change by 2050, and 18% of its coastland will remain inundated by 2080."

"The number of people estimated to be displaced by slow-onset events will stand at ∼22.5 million by 2030 and ∼34.4 million by 2050."

"The fact that an overwhelming share of those displaced by climate around the world resettle internally indicates that adaptation in-country is the most viable option. ... However, it requires adequate international support, which developed countries are obligated to deliver."

"Unfortunately, adaptation finance continues to remain the 'poor cousin' of mitigation, the ratio remaining 20:80 despite repeated pledges by developed countries and agencies."

From @katharine_mach and @sidersadapts, "Reframing strategic, managed retreat for transformative climate adaptation": "Human societies will transform to address climate change and other stressors. How they choose to transform will depend on what societal values they prioritize."

@katharine_mach @sidersadapts "Managed retreat can play a powerful role in expanding the range of possible futures that transformation could achieve and in articulating the values that shape those futures."

@katharine_mach @sidersadapts "Most climate adaptation to date has been small scale and short term... The level of ambition and innovation in adaptation falls substantially short of the challenges posed by current, much less future, climate risks."

@katharine_mach @sidersadapts "Adaptation visions have the potential to be bold, in pursuit of futures prepared for climate shocks that promote social justice, improve quality of life, and foster stronger relationships between peoples and between people and nature."

@katharine_mach @sidersadapts "Retreat is controversial because it challenges the status quo and has potential to cause major and inequitable losses."

@katharine_mach @sidersadapts "Conversely, retreat has enormous potential to inform adaptation precisely because it challenges the status quo, raises difficult questions about justice, forces people to confront the inevitability of change, and encourages people to make mindful choices about trade-offs."

@katharine_mach @sidersadapts "Strategic, managed retreat may not be implemented in many places. Yet bringing it into adaptation conversations now, despite (or even because of) its complexities, creates better chances of long-term, sustainable well-being under intensifying climate risks."

@katharine_mach @sidersadapts We will be rebuilding. The question is how. (x/x)