More than 45,000 acres on Oahu should be designated as important agricultural lands and required to stay that way in perpetuity under a new plan submitted by Mayor Kirk Caldwell to the Honolulu City Council.

It’s taken half a century to get this far. Now comes the hard part: getting something through the Council.

In the 1978 Constitutional Convention, voters ratified an amendment to the state Constitution that mandated that so-called important agricultural lands, or IAL, be identified and designated.

In return for their commitment to continued agricultural use, property owners are supposed to receive incentives from the state and city governments.

The 1,800 parcels identified in the Report on Oahu Important Agricultural Land Mapping Project represent about 12 percent of the island’s landmass.

Of Oahu’s 386,000 acres, roughly 128,000 (32 percent) are classified as agricultural, and about 12,300 already have IAL designation at the request of landowners.

A majority of the lands recommended for IAL status under the new plan are in Central Oahu (Mililani, Kunia and Wahiawa) and the North Shore (Haleiwa and Waialua), but there are also several large tracts along the Waianae Coast and the northeastern regions of Koolau Loa and Koolau Poko on the Windward side of the island.

The Council must act on the mayor’s plan, or its own version of it, and then submit it to the state Land Use Commission for a final decision.

Caldwell said community meetings held by the Department of Planning and Permitting across the island have been heated, and he expects that to continue. “People are wanting more or wanting less. Everyone seems to be upset one way or the other,” he said.

But Caldwell and DPP officials view it as imperative to finish the project and forward the city’s recommendations to the LUC.

“Agriculture has an important part on our island, not just the neighbor islands,” he said. “It’s about the long-term impacts — how do we remain resilient and sustainable, and how do we keep agriculture alive? Even if some of those lands aren’t farmed today, I believe sometime in the future if the economics change, they could become more viable for farming.”

Growing concern about climate change and sea-level rise have heightened the urgency to complete the study, said Josh Stanbro, Honolulu’s chief resiliency officer.

“Food security is one of the biggest challenges of climate change,” Stanbro said. “Increasingly, we’re seeing drought and extreme weather conditions hampering big global food production.”

Available water, sufficient labor and long-term availability of land are the biggest impediments facing local farmers, Stanbro said. By designating IAL properties, “this hopefully gives them the land base in the future to really farm on and put their roots out in and be able to invest for the long term because they’ll know the rug’s not going to be pulled from under their feet.”

However, some landowners strongly object to keeping their property designated agriculture in perpetuity.

“They don’t want to be designated because they want to have the ability to at some point to come in and change zoning in communities where they think they could build housing, and they’ve asked me to slow it down or to exclude their properties,” Caldwell said. “Some of it is really some of the best farmlands on Oahu, and we have not done that. So I’m sure they’ll be before the Council.”

David Arakawa, executive director of the landowner-backed Land Use Research Foundation and a member of the city’s technical advisory committee, said the situation is more nuanced than what Caldwell described, adding that he and others on the task force were surprised to learn through the Honolulu Star-Advertiser the Caldwell administration had finalized a plan, made it public and submitted it to the Council. Several LURF members have been in discussion with the mayor and city officials about which of their lands should be designated IAL, and they believed those talks were ongoing, he said.

At the very least, the committee should have been given the opportunity to review and make further suggestions on the final draft, he said.

He expressed concern that the city has not conducted surveys of the lands they propose to designate IAL and thus cannot be sure they meet the criteria for the designation.

“The city’s consultant primarily relied on technology (not actual site visits) to make its initial recommendations for IAL designations,” Arakawa said. That led to “inaccurate information and erroneous and unfair proposed IAL designations.”

The selection of IAL was “resource-based,” acting DPP Director Kathy Sokugawa said. “It didn’t matter who owned the land; it didn’t matter where the property lines were. We just went with the criteria.”

Initial designation was given to agricultural lands that met one or more of three top criteria: lands currently being used for agriculture; lands with enough available water for agriculture; and soil conditions conducive to agriculture.

Arakawa said committee members agree those are the most important criteria but believe water availability to be the most significant factor and an absolute requirement before lands can be designated as IAL.

LURF is also raising objections because the report submitted to the Council does not include landowner incentives as mandated by state law, Arakawa said.

“The county IAL designations can only take effect three years after incentives and protections for IAL and agricultural viability are enacted by the county,” Arakawa said. “The failure to enact IAL incentives could delay the county designation process for three years after the county enacts IAL incentives.”

Sokugawa said the city is looking at incentives and intends to submit a separate measure to the Council.

Because there are incentives already in place at both the state and city levels for standard agricultural use, it’s difficult for the city to find additional ones to provide those with lands designated IAL, Caldwell said.