Unprecedented challenge: implications for climate resilient urban planning

Abstract

Reckien et al. (2018, 2019) provide an extensive overview of the global status of CC (climate change) planning and find that less policy activity is taking place in adaptation as compared with mitigation, and that CC adaptation (CCA) initiatives are at an early stage, however, with Northern Europe being a frontrunner. Salvia et al. (2021) analyse 327 European cities’ climate mitigation plans and conclude that the current mitigation actions by cities are not ambitious enough to meet the Paris Agreement that aims to limit the global mean temperature rise this century to below 1.5°C above pre-industrial levels. To meet this target, European cities need to double their efforts. Looking at the observed climatic changes, the observations currently follow the high-end scenario of the UN Intergovernmental Panel on Climate Change (IPCC), termed the RCP8.5 scenario. This scenario is the Business as Usual (BAU) scenario, meaning the expected rise in temperature if the GreenHouse Gas (GHG) emissions remain unchanged. The development of CO2 in the atmosphere provides no indication of bending the curve, measurements by NOAA show an increase from below 380 parts per million (ppm) of CO2 in 2005 to above 410 ppm in 2020 (NASA, 2020). To return to the levels of pre-industrial times, Bill McKibben and his 350.org campaign argues for a reduction of CO2 levels in the atmosphere to 350 ppm. Following the RCP8.5 scenario we are to expect an increase of global mean surface temperature to 4.8°C by the end of the 21st century (2081–2100) relative to 1986–2005. Temperature increase alone will cause sea level to rise between 0.45 to 0.82 m for the RCP8.5. scenario, whereas the contribution of melting ice from Antarctica and Greenland is not fully understood (IPCC, 2014). The sea level does not rise evenly across the globe due to regional changes in the gravitational field and land uplift. Grindsted et al. (2015) find that there is more than a 25% chance that the 0.82 metre figure is surpassed in