City to city learning and knowledge exchange for climate resilience in southern Africa

climate change at city governance level. While we recognize that cities are context-specific we consider these good practices as being broadly transferable to other southern African cit- ies. We conclude that social, experiential and structured learning can be an innovative way of multi-stakeholder engagement and a useful approach to increase city resilience planning across southern Africa and cities that face similar developmental challenges. Introduction Southern African cities, being densely populated, urban environments with expanding popula- tions as compared to the rest of the countryside, are vulnerable to harsh weather, climate vari- ability, extreme climate events and associated risks among other factors [1]; [2]; [3]; [4]; [5]; [6]; [7]. For instance, droughts often experienced in cities like Cape Town and Windhoek and currently across the southern African region because of low rainfall levels this past rainy season of 2018/2019 have become more frequent, intense and widespread [8]; [9]) while variations in inter annual rainfall have increased in the past half century [10]. These extreme events are pro- jected to likely increase in the future [11]; [12]. Cities play a tripartite role when it comes to cli- mate change as they are contributors to climate change through greenhouse gas emissions; bear the brunt of climate change; and can simultaneously be places of climate change (trans- formational) adaptation through innovation and solutions that can build resilience [13]; [14].

Cities in southern Africa face a multiple stressor context with several development challenges including inadequate water provision, mismanagement, governance and infrastructure chal- lenges and lack of financial resources. At the same time, these and other cities function as eco- systems which are connected through processes that function at multi-scalar and high levels of complexity [15]; [16]. The city-space, is therefore characterized by complexity, and multiple, interconnected subsystems or ecosystems [17] in which city planning and implementation should be considered using a climate-resilience development lens. Notably, the interaction of physical ecosystems with the built environment, social and financial systems, environment and climate is indeed complex, even more so in rapidly urbanizing African city regions where intricately, interconnected infrastructure, institutions and information form the urban ecosys- tem. Understandably, there is growing concern about the resilience of these urban areas, particularly in vulnerable and underdeveloped regions such as southern Africa, given the con- nectedness and fragility of the urban ecosystems and the need for transformative over an incre- mental adaptation and mitigation agenda even under 1.5˚C average global warming trends [16]. The multi-stressor context, which is compounded by climate change and variability, means that these cities need to respond swiftly, flexibly and creatively to develop systematic, systemic, sustainable and resilient solutions to the climate crisis. The multi-stressor context requires

numerous responses, which may consist of responses in physical planning such as ‘hardening up of infrastructure systems, including storm-drainage systems, water supply and treatment plants with protective physical improvements; protection or relocation of solid waste manage- ment facilities, energy generation and distribution systems; and consolidation of hydro-geo- logically fragile areas’ [18], and/or ecosystem- and community-based adaptation [19] coupled with the transformative adaptation agenda given that resilient development now requires nothing less than transformational change [20]; [21]. At the same time, processes that foster adaptation, mitigation and resilience building such as learning from and adopting best prac- tices are essential. Learning is essential for cities to adapt to current and future challenges. One City learning in southern Africa PLOS ONE | https://doi.org/10.1371/journal.pone.0227915 January 24, 2020 2 / 25 under the IDRC’s African Climate Change Leadership Program (AfriCLP) (2018-2019). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist.