Nature-based methods, such as planting more urban greenery or designing and building natural watersheds, are a popular city improvement to increase climate resilience.
While increasing urban greenery plays a key part in most city adaptation plans (72%), along with other areas with enormous potential to promote biodiversity, only 18% of plans specifically addressed biodiversity.
This is a missed opportunity for human adaptation responses that could have biodiversity conservation outcomes in cities.
Fig 1: 80 cities with adaptation plans assessed (all circles). While there is some inevitable spatial bias (due to the selection criteria), all urbanised continents are represented in the analysis. Increasing depth of colour (pale yellow–dark orange) represents the increasing number of threatened species per city (from 1–5 to 36–40: see key). Grey circles indicate no threatened species data available.
As part of our study we found 151 cities across 51 countries and six continents with climate change adaptation plans. Of these, 80 were readily available online and primarily in English and were analysed in detail.
These plans included almost 13,000 square kilometres of proposed reforestation, that could help sequester carbon from the atmosphere, and 5,872 kilometres of waterway actions, that can help take rainfall from increased storm activity.