The images of water crushing homes in Sendai, Japan, have already started to fade. We breathe, relieved that Hawaii dodged another tsunami.

But an unseen tsunami has already come ashore, an economic wave punishing our islands from two directions: from Japan, where disaster is driving down Hawaii-bound tourism, and the Middle East, where conflict is driving up the price of oil.

Fewer tourists mean less money in the local economy. Rising oil prices mean everything costs more, since we import goods on oil-burning barges and planes.

This moment has us awash in uncertainty. It is a challenge, both a time of difficulty and a call to action.

Japan’s experience reminds us that neighborly kokua is crucial in times of crisis. Declining tourism and spiking prices remind us how vulnerable we are to world events. Depending on each other, rather than distant resources, is the surest way to make an island society more secure.

Every state plan since the 1970s says Hawaii must build a more secure, sustainable economy, but it’s been hard work to wean ourselves from tourism, imports and the military.

Today we have a chance to start that work, start with ourselves, and start with four steps:

» Prepare together: Reach out three doors in both directions from your home. Get to know your neighbors better. Exchange emergency information and prepare together.

» Cut oil use by 25 percent: Leave cars home once a week and bike, bus or carpool; wash with cold water; use fans instead of air conditioners; replace light bulbs with energy-efficient CFLs.

» Eat home-grown: Substitute food grown or caught for bought food once a week. Tap the papaya tree for breakfast instead of that $6 box of cereal. Build a school or community garden. When you buy, buy local.

» Replace disposables: Use cloth napkins and reusable plates and utensils instead of disposable paper and plastic. Disposable stuff costs money and ends up in landfills or incinerators.

Let’s tackle this challenge together and reach for this ambitious goal: One year from now, 50,000 households have adopted these changes across Hawaii.

These steps will save a typical household $1,500 a year in tough times. Together, 50,000 families would save $75 million, and remaining spending would support sustainable businesses. These steps also would begin a shift in our economy — from the bottom up — that makes it more secure in the long run.

For our part, Kanu Hawaii will organize several monthlong "Challenges" this year, encouraging our 14,000 members to "be the change," one change at a time:

» A "Live Aloha in Your Neighborhood" challenge, to connect with neighbors, starting this month;

» An energy challenge to cut energy bills dramatically, in July;

» An "Eat Local" challenge urging home-grown eating, throughout September;

» A reuse challenge, during the waste-heavy holidays.

Kanu will publish how-to’s, host workshops, keep count of people and track impacts. But the work is bigger than Kanu; helping 50,000 households respond to these challenging times will take a massive, determined hui of people and organizations.

Change will not come without sacrifice. All of us will have to lower fences and live with less seclusion. We’ll have a little less variety (no peaches in December). We’ll have to learn new things, like how to grow food instead of lawns. We’ll need to invest in upgrades that enable more efficient and renewable energy.

These changes will enrich our lives beyond saving us money. They define a simpler way of life many of us long for. A life with less stuff and more relationships. A life lived closer to the land and to each other. A life designed for the place we live.

An island life.