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Why Climate Change Is Especially Dire for Islands

The author of Sea Change explains the frustration, grief, and anger of the people at the forefront of the environmental crisis.

Published on November 29, 2023

In the first installment of a new collaboration between the University of California Press and Carnegie California, senior fellow Darshana Baruah speaks with Professor Christina Gerhardt about her book, Sea Change: An Atlas of Islands in a Rising Ocean. The interview has been edited and condensed for clarity.

Darshana Baruah: At Carnegie, I spearheaded a dedicated initiative on understanding priorities and challenges important for island nations. A key aspect of this project is recognizing climate change as a national security threat. As a result, I was thrilled to read your book about islands from around the world. What are the main points you aim to capture in Sea Change?

Christina Gerhardt: Sea Change is what I call a symphony or a chorus: it weaves together maps, essays, poems, and art to illustrate the histories and cultures of islands, as well as environmental science to explain the impacts of sea-level rise and environmental engineering to share the solutions.

Sea Change features forty-nine islands. It opens with Greenland, which is the largest island in the smallest ocean and one of the two main motors, or engines, that fuels the sea-level rise. Sea-level rise has two main sources, and one of them is the melting of land ice and glaciers at the poles—for example, the Arctic, Greenland, and the Antarctic. The other source of sea-level rise is thermal expansion—as waters warm, they expand and take up more space.

The first chapter on Greenland is followed by a poem by Greenlandic Inuit poet Aka Niviâna and Marshall Island poet and climate envoy Kathy Jetn̄il-Kijiner. Their poem is titled “Rise.” It points out that the melt that you have at the poles impacts low-lying islands halfway around the world. It highlights how we are all connected.

We can also think about how environments as ecosystems are connected. If we hear about the air temperature increases worldwide that hit us this past summer, for example, we should think about ocean temperature increases because the oceans have absorbed so much of the air’s heat. Those high ocean temperatures off the coast of Florida—hitting 100 degrees Fahrenheit, the temperature of a hot tub—should have us thinking about sea-level rise because of thermal expansion.

It is a huge problem because the oceans are stuffed. They have already absorbed 90 percent of the heat resulting from emissions. They cannot absorb any more.

Darshana Baruah: A key aspect of our conversation with island nations has been about understanding the different impacts of climate change and how they are framed by nations big and small. Climate change is a consequential issue for many nations, but the impact and scale varies significantly by country. The impact of sea-level rise, and the calculations and considerations that need to be made by, say, the state of California and the people of Maldives, will be completely different, right?

Christina Gerhardt: Right. One of the crucial differences between continents and islands is the ability to move inland. Almost half, about 40 percent, of the U.S. population lives in coastal states and cities. That is a really high percentage of U.S. residents, about 13 million, who are going to be affected—in order of impact in Florida, Louisiana, California, New York, and New Jersey. But residents on a continent can retreat inland. For many islands, like the Maldives, sea-level rise may spell the end of their nation’s very existence.

In Sea Change I talk about two different kinds of islands. Volcanic or high islands are, as the name suggests, islands with volcanoes, so they’re higher. The other kind of island is low-lying islands or atolls. They are often ring-shaped and rest atop the rim of an extinct and submerged volcano. They tend to be no more than roughly nine feet in height and transient in nature.

The Marshall Islands is an atoll and rests on average six and a half feet above sea level. Atolls or low-lying islands like the Marshall Islands are going to be most impacted. Aside from the Marshall Islands, Kiribati, Tuvalu, and the Maldives are the islands most at risk, globally, of being completely inundated by sea-level rise. But people on volcanic islands are also impacted because they tend to have steep slopes, and that inclined terrain means that they are often more clustered around the coastline.

Population density is something I tracked throughout Sea Change. It is not just the people on the coastline on volcanic islands that are impacted—it is all the infrastructure that they bring with them. It includes everything from airports to roads to wastewater treatment facilities, the facilities that provide us our clean drinking water, and power plants, which are often located by water. And of course, the ecosystems are affected, too.

Darshana Baruah: We often talk about small islands being at the front of experiencing climate change. In Carnegie’s work with island nations we have heard that small states can be vulnerable but not powerless, signaling the important work islands do in initiating change and driving climate action. Would you share with us a little more about your work on how climate change will impact island states?

Christina Gerhardt: I think inequality is a really crucial frame to answer this question. This is one of the reasons why at the annual UN climate negotiations you see a real push by nations from the so-called Global South—so nations that have produced negligible amounts of CO2 emissions, and most but not all islands belong to that category—pushing nations in the Global North, which are historically the largest emitters and financially more affluent, in part due to the history of colonialism, to take responsibility for their larger emissions and to share resources (such as monies and technology) to help frontline communities address sea-level rise impacts.

What are the impacts on islands specifically? Aside from sea-level rise inundating the infrastructure that I mentioned, or interfacing with the population density, salt water often inundates the soil on low-lying islands. This salinization upsets the soil’s pH balance. Plants cannot take up salty water, so they cannot grow. The communities on many atolls are subsistence farmers or fisherfolk. They rely on what they grow and what they fish to sustain themselves. So, salinization impacts their agricultural yields and self-sufficiency intensely.

Low-lying atolls typically also do not have rivers running through them. (That’s another feature distinguishing volcanic islands from atolls.) Atolls get their water from fresh-water aquifers and rainwater catchment. If you have saltwater lapsing into the aquifers, it can contaminate that water. So again, the water is too salty, rendering it undrinkable by humans and animals and useless for most plants.

Darshana Baruah: I found it really interesting that your book also covers undersea cables, which really is the main form of fiber-optic cable that is connecting every corner of the world. I was wondering if you could share a little bit in terms of changes within the ocean economy, because if there are disruptions in internet access, it’s not going to impact just islands.

Christina Gerhardt: I talk about this issue in a couple of different locations in Sea Change. I draw on the work of Nicole Starosielski and her book TheUndersea Network in which she talks about this kind of infrastructure. She makes a really important corrective to common misperceptions about how our modern communications work: we spend so much time talking about Wi-Fi and the cloud, and everything therefore seems to be up in the air, but the infrastructure of communication cables is underground and undersea. Furthermore, Starosielski points out that a lot of the undersea network that we use now is layered on top of prior cables that anchored the colonial telegraph system. So even if we think it is twenty-first-century infrastructure, it is layered on top of prior colonial infrastructure.

In terms of geopolitics, I talk about how undersea cables around the Seychelles, Mauritius, and the Comoros are being layered on top of infrastructure from these these islands were used as military bases. They were used to refuel military planes. And navy ships gathered intelligence and surveilled islands or the surrounding region. So contemporary undersea cables are layered on top of not only colonial but also military infrastructure.

In terms of geopolitical interests, islands function as hopping-off points. They are not considered from the ground up in terms of the people who are there, their histories, their cultures, their wishes, and their needs. See, for example, the situation of the island Diego Garcia, whose residents, the Chagossians, were forcibly evacuated by the UK to Mauritius and the Seychelles, so that the United States could build a naval base, which is named Camp Justice. This top of use is mobilized from a top-down, colonial, now imperial, militaristic structure for the needs of the entity that is using that part of the island, and that history is really important.

Darshana Baruah: From your experience of writing Sea Change, was there any topic or issue that you thought was a common thread throughout the different geographies that you covered that was not very obvious to people who are not from islands?

Christina Gerhardt: I think the thing that struck me in working on Sea Change is how dire the situation for many islanders is and how consistently vocal they have been. I think a lot about how much frustration, grief, and anger the islanders have to be navigating while they are also negotiating at the UN climate conference for their urgent needs to be addressed. These needs related to the climate crisis were brought about by the Global North, which is not allocating enough resources either in terms of monies or technologies.

If a reader is located in the Global North, I think it is really important to be aware of the privileges that one has—the ability to impact these decisions—and that action is better than inaction. There are so many different ways of engaging in this process, whether that means internationally, nationally, or locally, be it via politics, NGOs, or working to restore oyster reefs, wetlands, coral reefs, or mangroves.

What I found over the course of doing the research for Sea Change—which involved hundreds of interviews with scientists, climate envoys, frontline communities, fisherfolk and farmers—is how much work islanders are already doing to address these impacts. Islanders are already solving this crisis because the Global North is not doing enough.

See more of Carnegie’s work on climate and COP28.

Carnegie does not take institutional positions on public policy issues; the views represented herein are those of the author(s) and do not necessarily reflect the views of Carnegie, its staff, or its trustees.