Sam Lemmo, administrator of Hawaii’s Office of Conservation and Coastal Lands, takes a dire view of the impact of sea level rise on his state.

“It is going to become a ‘Planet of the Apes.’ Charlton Heston on the beach, pulling his hair out, screaming, ‘Why did we do this to ourselves?’ That’s the future I foresee,” Lemmo said during a forum for Hawaii’s Environmental Council last week. The council serves as a liaison between the director of the state’s Office of Environmental Quality Control and the public on issues related to ecology and the environment.

The June 16 forum brought together state experts to speak about the impact of climate change on Hawaii and the world at large. Following is more of what we heard at the event.

Dangers of Shoreline Erosion, SLR

Chip Fletcher, associate dean for academic affairs at the University of Hawaii’s School of Ocean and Earth Science and Technology, said the sea has risen eight inches since the 1800s and that continued sea level rise (SLR) is “unstoppable.” Fletcher quoted Michael Oppenheimer, a contributor to the International Panel on Climate Change, as saying, “There is no scenario that stops sea level rise in this century. We’ve got to deal with this indefinitely.”

Maui is in particular danger of shoreline erosion, said Tara Owens, coastal hazards specialist with the university’s Sea Grant College Program. While 70% of Hawaii’s shoreline is eroding over the long term, that number increases to 85% for Maui. Maui also has the highest amount of beach loss at 11%.

Explaining why Maui is losing beaches faster than other islands, Owens said “it has to do with island subsidence. The sea level is rising for all of us, but the Big Island and Maui also have this issue with island sinking, because of the Big Island’s constant growth and settlement on the flexible lithosphere.”

Ruby Pap, coastal land-use extension agent with the Sea Grant College Program, said that 8% of beaches on Kauai have been lost, mostly due to “armoring,” or building a seawall to protect assets on land. Pap noted that “it’s much easier to change new development than to move existing development out of harm’s way.” She said Kauai could suffer a financial loss of $124 million with a 3.2-foot SLR.

Zero Emissions May Not be Good Enough

Fletcher shared a June 1 article he wrote for The Hill entitled, “It’s not enough to cut emissions — we need economic development that does not destroy nature.” In the piece, and his presentation for the forum, he argued that nature’s systems for cooling and carbon sequestration are predicated on a balance that is being disrupted by climate change.

According to Fletcher, about 30% of carbon dioxide emissions are removed from the atmosphere via photosynthesis. This process, however, has a thermal maximum, after which carbon uptake sharply declines, and could decline by 50% by 2040. He said this effect has not been accounted for in most plans to reduce global warming and noted that, from 2010 to 2019, Brazil’s Amazon flipped from a carbon sink to a carbon emitter — producing 18.3 billion tons of CO₂ but sequestering only 15.3 billion.

Fletcher said that although the Arctic is the “world’s refrigeration system,” it is warming at a speed “two to three times the global average” and that the glaciers of West Antarctica are in irreversible retreat. He also noted that as air temperatures increase, the ocean will absorb some of that heat and thermally expand, adding to SLR. He explained that the vertical transfer of temperature in the oceans can take “many centuries, in fact, over a thousand years” to fully equilibrate with the warmer air temperature.

Fletcher said that deforestation, which he claimed is largely the result of rich nations’ demands for goods (such as lumber, minerals, precious metals), along with the increased damage already being done by climate change, is exposing soil oxidation, which emits carbon. His article for The Hill said that “on average, 19% of the carbon in Earth’s biosphere is stored in plants, and 81% in soil.”

Commenting on the irreversibility issue, Lemmo said that “we can never stop [climate change] … All we can do is manage it better than we would have if we had done nothing. That’s my take on it, anyway.”

Moving Forward

Bethany Morrison, long-range planner for Hawaii County on the Big Island, said her county is working with Germany-based ICLE, which helps local governments worldwide create sustainable urban development, to help integrate both climate change adaptation and mitigation into the county’s urban planning.

Morrison said that because “we don’t have the resources to really address” specific places, Hawaii County’s climate plan would instead look for a more “regional approach” to use funds more efficiently and minimize the energy put into individual assets.

The county’s climate plan focuses on a “multi-hazard” approach, Morrison said. It requires all coastal development to incorporate measures to address SLR, regulates development in high-risk areas for erosion and updates high-risk hazard zones to be more accurate.

Morrison also explained that the county has a “research-based” project that would identify historic shoreline change and riparian bluff retreat rates and recommend mitigation strategies. She said because Hawaii Island has few sand beaches and a varying shoreline geology, quantification is harder, which is forcing officials to “think outside the box.”

Owens explained that the western Maui shoreline is particularly vulnerable to erosion and flooding due to the nature of ocean swells throughout the year, leading to the creation of the West Maui Wave Run-Up Forecast. The system uses community photos taken through a phone app to calculate what a given swell is doing in a specific location, which can be extrapolated to create a more accurate understanding of the entire swell. Owens called it “kind of like a six-day weather forecast for waves.”

In response to a public question about providing tax credits to homeowners near shorelines to elevate their homes, Lemmo said “It’s an interesting thing, giving tax credits. Please don’t take this the wrong way, but it’s like giving tax credits to people that buy EVs. Yeah, it’s a fantastic way to sell EVs, but in some ways it’s simply a benefit to the rich people; we all end up having to pay the bill on that.”

Lemmo said that people who own coastal property usually have resources. “Should we be using tax funds that could be used for mitigation measures by giving these people tax breaks? I don’t know. That’s a policy call at a very high level.”

“Elevation can work really well if it’s a flooding issue, but if it’s a coastal erosion issue and you’re losing land, then elevation may not be a good adaptation tool,” Owens said.

“Frankly, I don’t have a solution to this problem,” Fletcher said about erosion. “How are we going to get out of the way of rising sea level on those beaches that we want to be sure are here for our grandchildren?”

Fletcher noted that some in the environmental field refer to them as legacy beaches. “What is the legacy we are going to leave on our shoreline? Is it going to be a legacy of seawalls and beach loss, or is it going to be a legacy of preserved beaches? … How are we going to do that?”