By 2100, Boston could be four to seven feet underwater. In the worst-case scenario, scientists declare the city will be a staggering fifteen feet underwater.
Climate change accelerates the thermal expansion of water and the melting of glaciers at the poles, causing sea levels to rise at astonishing rates. This threatens coastal cities across the globe, creating problems like high-tide flooding, extreme precipitation, and more destructive storms. In response to rising sea levels, many foundations and initiatives are allocating funds to combat it, but this is not enough.
Many state and city legislatures are mandating more traditional “hard” or “gray” solutions—such as concrete seawalls—rather than nature-based solutions that offer a more efficient and sustainable approach. However, for their protection, coastal cities like Boston should incorporate more nature-based solutions into their legislation and promote research on green solutions, given their ability to support wildlife habitat, provide ecosystem services, and mitigate climate change.
One disastrous effect of rising sea levels is the loss of coastal ecosystems, such as salt marshes, which provide an environment for many plants and animals to thrive. As sea levels rise by over 4.5mm each year, low-marsh organisms move to higher ground and high-marsh organisms decline in population. Therefore, gray solutions that focus solely on protecting man-made infrastructure further harm already strained habitats and disrupt the coastline’s natural functions. Conversely, nature-based solutions produce the same result while promoting and restoring the collapsed ecosystems. Nature-based solutions, such as mangroves, help reduce erosion and storm impacts associated with rising sea levels. Mangroves, in particular, reduce annual flooding and save around $65 billion a year. As a result, the effects of land loss from rising sea levels are mitigated, saving countless organisms and wildlife that call coastal ecosystems home.
In addition to restoring habitats, nature-based solutions can provide many ecosystem services, or natural benefits, to both the cities they protect and the people who live in them. While gray solutions focus solely on mitigating the effects of rising sea levels, nature-based solutions can accomplish multiple objectives at once. For example, one of their many assets is water purification. More specifically, these solutions can replenish nutrients in the water and improve its quality. By doing so, cities can save funds that would otherwise be used to improve water quality and cleanse it of pollution. Furthermore, maintaining water quality and marine life along the coast supports local fisheries and aquatic recreational activities. In turn, the city's revenue increases from restored marine habitats and the ecotourism it attracts.
On a different note, another essential benefit of nature-based solutions is their ability to slow climate change, which is a major driver of rising sea levels. By doing so, it creates a negative feedback loop in which rising temperatures and rising sea levels balance and stabilize. One reason for this is carbon sequestration. Many of the marine vegetated habitats involved in nature-based solutions account for 50 percent of carbon burial by ocean organisms—in other words, they absorb the carbon dioxide in the atmosphere that contributes to Earth's global temperature rise. This ensures that ocean water doesn’t expand as much and that the glaciers at the poles aren’t melting as quickly due to heat. Additionally, these nature-based solutions can continue to mitigate rising sea levels by acting as barriers and reducing wave impact during floods, adapting to the changing climate. The deep roots of these plants can also trap seafloor sediment and reduce erosion, helping keep pace with rising sea levels and reducing land loss.
While there are many benefits to nature-based solutions, one major concern with mandating them in coastal cities is the limited space available in urban settings, since most require large areas to thrive. Another issue is that certain ecosystems require specific conditions to survive. However, the positive effects of these solutions far outweigh their concerns. Furthermore, there are many ways to overcome these barriers, such as having cities customize nature-based solutions best suited to their urban areas and mandate them in their legislation. This would allow cities to implement the best solutions for their cities and create new systems designed for their cityscapes. One example of a successful nature-based plan is the Emerald Tutu Project, which operates around the city of Boston to develop floating vegetated canopies to mitigate the effects of rising sea levels, flooding, and storms. Designed for the city, it allows recreational water activities while reducing small-wave energy by up to 90 percent.
To protect both our cities and ecosystems, we will need more projects like the Emerald Tutu. Even if we stop our carbon emissions today, sea levels will still rise, threatening coastal cities worldwide. Cities need to mandate the development of nature-based solutions in their legislation, and spreading this message to your local city committee is the start.
The views expressed in this op-ed are those of the author and do not necessarily reflect the official position of the Saving the Sea Organization. This piece was written as part of the Emergent Fellows Program, our summer fellowship in environmental policy and advocacy.