Many cities globally are forging ahead with climate change adaptation, even as some national governments are slow to respond or even deny the core science demonstrating climate change. While movements to adapt to climate change may seem sensible for cities, particularly those that face immediate threats such as higher sea level change, cities might also miss opportunities to best adapt by not integrating biodiversity in their plans.
Cities contribute greatly to emissions that influence climate change; however, their urban areas also overlap many areas that have potential for biodiversity. A recent study showed that many major global cities, such as New York and London, have plans to limit greenhouse emissions or other actions that can benefit climate change, but are doing little to address the natural biodiversity these areas can support. For instance, cities have been found to have greening plans, such as planting trees, but these plans often do not promote natural flora that could be found in the areas where cities exist. Cities along major coastlines are vulnerable to sea level rise; however, it is known that shoreline swamps can be effective in acting as effectively sponges in absorbing excess storm surges. Many swamplands are not being restored but rather are being replaced with other ecosystems, often not having as much benefit in climate mitigation and adaptation. Additionally, simply planting trees may not be sufficient, as certain species planted in given biomes may actually have limited benefit to climate mitigation due to limited albedo effect. Wildlife also helps promote balance in biodiversity and can aid in different vegetation being preserved through creating a healthy tree cover balance. Additionally, current plans may promote more vegetation in urban areas, but these plans could become expensive if they require significant human intervention, such as large-scale watering, rather than utilizing natural biodiversity to maintain created ecosystems. From current research, it is clear that most cities have not accounted for biodiversity and this may need to be reassessed in light of existing climate change plans these cities have.
Additionally, studies continue to show that ecosystem services, that aid in the production of food or help with nutrient cycles in our environment, are critical for the health of cities. The correlation between healthy ecosystem services and biodiversity has been show as being important for urban contexts, but this has generally been under-emphasized in plans being created, or even measured, for urban areas to adapt to climate change. Creating cities that better balance biodiversity, while also measuring it as part of their plans, could help strengthen food supplies while improve the health of rivers, streams, and areas that can mitigate flooding or other detrimental effects of climate change. Part of the problem might be the need for cities to continue to grow and the face they have to deal with increased migration as the world becomes more urbanized. Biodiversity increasingly suffers as land around and within cities is utilized as urban space or for construction, leading to limitations on biodiversity. Without mitigating the conflict between land use change and urban growth, then biodiversity will increasingly be harder for most cities to address.
Nevertheless, despite the need for more cities to promote increased biodiversity in their climate change adaptation efforts, some cities are beginning to better address biodiversity, demonstrating there is potential for cities to thrive. For instance, Charlotte, North Carolina was seen as a city that had approached urban forestry in a positive way by diversifying its natural variety of tree species in the region. In this case, they used a mix of oak, hickory, and pine trees, which helped to mitigate flooding, provide a health, nutrient cycle to soils and animal species, while also acting as carbon sinks. Overall, such plans are not expensive but they can be relatively cheap for cities while also being inexpensive to sustain, in addition to providing both global-scale and urban-scale benefits.
Biodiversity is seen as an important component in helping to mitigate and adapt to climate change. Few plans among major metropolitan regions are considering this aspect of their climate change plans; however, with increased research showing the benefits of biodiversity, urban regions may increasing face pressure to adopt biodiversity as part of their overall climate adaptation plans.
 For more on biodiversity that could help mitigate climate change in urban environments and current urban plans and how they lack biodiversity plans, see: Butt, N., Shanahan, D. F., Shumway, N., Bekessy, S. A., Fuller, R. A., Watson, J. E. M., et al. (2018). Opportunities for biodiversity conservation as cities adapt to climate change. Geo: Geography and Environment, 5(1), e00052. https://doi.org/10.1002/geo2.52.
 For more on ecosystem services, climate change, and their relation to urban environments, see: Knapp, S., Haase, D., Klotz, S., & Schwarz, N. (2018). Do Urban Biodiversity and Urban Ecosystem Services Go Hand in Hand, or Do We Just Hope It Is That Easy? In S. Kabisch, F. Koch, E. Gawel, A. Haase, S. Knapp, K. Krellenberg, et al. (Eds.), Urban Transformations (Vol. 10, pp. 301–312). Cham: Springer International Publishing. https://doi.org/10.1007/978-3-319-59324-1_16.
 For more on biodiversity loss and conflict between human needs and biodiversity in urban regions, see: Rastandeh, A., Pedersen Zari, M., & Brown, D. K. (2018). Components of landscape pattern and urban biodiversity in an era of climate change: a global survey of expert knowledge. Urban Ecosystems, 21(5), 903–920. https://doi.org/10.1007/s11252-018-0777-3
 For more on Charlotte and other cities applying successful biodiversity planning, see: Chen, G., Ozelkan, E., Singh, K. K., Zhou, J., Brown, M. R., & Meentemeyer, R. K. (2017). Uncertainties in mapping forest carbon in urban ecosystems. Journal of Environmental Management, 187, 229–238. https://doi.org/10.1016/j.jenvman.2016.11.062