That well-worn phrase — climate change. We know it’s out there, hovering over our lives like a heavy cloud. But what does it mean exactly — to you and the Island of Martha’s Vineyard?

It means striking changes in the three most critical components of Island life:

• The natural environment — the air, land and water;

• Our physical well being — our human health;

• The local economy.

Not in the distant future, not at the end of the century, but now. And Martha’s Vineyard, this finite entity, this speck of sand in the sea, happens to be a mighty little microcosm of climate change disruption.

The earth’s climate has been stable for a very long time. The dramatic climate change we are now experiencing dates back to the industrial revolution, when oil, gas and coal replaced wind, water and wood as our main energy sources. These fossil fuels began emitting greenhouse gasses that are unnaturally warming the earth.

In the book, Hot: Living Through the Next Fifty Years on Earth, reporter Mark Hertsgaard offers an easy distinction between two confusing terms, global warming and climate change: “Global warming refers to the manmade rise in temperatures caused by excessive amounts of carbon dioxide, methane, and other greenhouse gasses in the atmosphere. Climate change, on the other hand, refers to the effects these higher temperatures have on the earth’s natural systems and the impacts that can result: stronger storms, deeper droughts, shifting seasons, sea level rise, and much else.”

The human race must conserve energy and quickly replace fossils fuels with renewable energy sources. But even a timely end to greenhouse gas emissions will not stop the climate changes that are already in motion.

Hotter, wetter, stormier; more severe summer droughts. That is the most basic climate change forecast for the Island. We are a community at risk.

The Vineyard is on the climate change frontline because initial impacts will be felt on the coast. And the Vineyard is not just any coast — it is surrounded by the sea, susceptible at every edge to sea level rise, storms, coastal flooding and shoreline erosion. To make matters worse, the Island is naturally sinking — or subsiding.

The Island shoreline is diverse. No single plan will protect the Gay Head Cliffs and north shore banks, the barrier beaches, ponds and salt marshes, the ferociously exposed south shore, the low-lying town centers. Beaches and banks will erode, roads and houses will flood, some will wash away. Salt marshes will disappear. Parts of the Island shoreline will, by necessity, be lost to the sea.

But the environmental impacts of climate change don’t stop where the sea meets the shore; they are exacerbated by the Island’s mix of rural, urban and suburban landscapes.

The crops we grow will be affected by hotter weather, more intense summer droughts, and heavier, more frequent rainfall in winter and spring. As will the timing of bird migrations, plant blooms, and pollination, all fine-tuned ecological interactions. Fire will become a more serious threat.

Suburban-style housing developments eat away at the woodlands, replace natural landscapes with less natural lawns and create a fringe habitat perfectly suitable for disease-causing pests such as ticks.

In the summer months, Tisbury and Oak Bluffs are, for all intents and purposes, urban centers — highly populated, densely developed, largely paved, and bound in part by hard structures like seawalls and causeways. There and in Edgartown the buildings, roads and utilities are vulnerable to storm damage, flooding and the rising sea.

The ocean is warming, too much so for marine species like lobsters and cod to flourish in local waters. Eelgrass, a prime shellfish habitat, is also stressed by warmer water temperatures.

Local climate change means more precipitation, hence more rain and flooding. On April 13 this year in a single day close to five inches of rain fell on the Island.

You may be thinking: It snowed like crazy in New England this winter — how can global warming be real? Eric A. Davidson says it best in his book, You Can’t Eat GNP; Economics as if Ecology Mattered: “Paradoxically, big snowstorms are entirely consistent with global warming. The expected changes in the climate will make winter both milder in terms of average temperatures and occasionally harsh in terms of blizzards and freak storms with lots of snow and freezing rain. Remember that it seldom snows when it is very, very, cold.” Snow, like rain, is a form of precipitation.

The human health impacts of climate change are as insidious as those of the environment, if not more so, and much less publicized. Thanks to a ground-breaking 2003 medical survey of the Island by Dr. Dianne Becker, director of the Center for Health Promotion at Johns Hopkins University, the human health of Island residents is well-documented. Five of the top six human health problems identified in the study, the Health Report of Martha’s Vineyard, can be linked to climate change: tick-borne diseases; allergies and asthma; chronic diseases including heart disease; depression and skin cancer.

There is already an epidemic level of tick-borne Lyme disease on the Island. Other vector-borne diseases such as West Nile virus are also climate-sensitive.

Warmer temperatures mean longer pollen seasons and more serious allergic reactions to tree pollen and ragweed. There is evidence that pollen is becoming more potent. Increased air pollution and rain (which means more mold) contributes to more asthma and other respiratory diseases.

Depression, according to the Health Report, is “quite common in full-time residents.” Some research has linked depression with chronic diseases including Lyme disease, allergies, asthma, and mold-related illness. Studies on catastrophic events like Hurricane Katrina make clear that loss of lives, homes and jobs is also linked to depression.

As temperatures rise the incidence of skin cancer — already high here in a beach resort community — is expected to increase.

The local connection between the environment, human health, and climate change is as clear as a the brightest summer sky.

And then there is the economy. There is no end to the reasons people are attracted to this Island, but the ultimate appeal is its graceful and circular shoreline. Coastal recreation — beaching and boating, fishing and shellfishing, the beauty of land mingling with water — is the backbone of the Island economy. Will people pay money to come here when beaches like Lucy Vincent erode away? When State Beach and Sengekontacket Pond become one? When there are too many jellyfish and algae blooms to swim in the ponds? Big property tax dollars will fall by the wayside when the sea overtakes waterfront homes.

These changes are going to happen whether we plan for them or not. The natural environment, human health, and the economy are the foundation upon which this community exists, and the foundation is being stressed by the weight of climate change.

Mr. Hertsgaard writes: “Over the next fifty years, climate change will transform our world in ways we have only begun to imagine. Humans have changed the weather on this planet, and that will change everything: from how we grow food and obtain water to how we construct buildings and fight disease . . .”

Dr. James Hansen, climatologist and director of the NASA Goddard Institute for Space Studies, who was the first scientist to report to a U.S. Senate committee in 1988 that manmade global warming was a reality, writes in his new book, Storms of My Grandchildren: “The startling conclusion is that continued exploitation of all fossil fuels on Earth threatens not only the millions of other species on the planet but also the survival of humanity itself – and the timetable is shorter than we thought.”

And here is an alarming insight from coastal geologists Orrin H. Pilkey and Rob Young in their book, The Rising Sea. While initial sea level rise impacts on U.S. development will naturally occur on island coasts, eventually “urban problems, especially stormwater and wastewater disposal, will begin to take precedence over preservation of beach communities. When our main population centers are truly threatened . . . small beachfront communities are likely to become declining public priorities.”

On a global level climate change is overwhelming. On the Vineyard, a finite unit, it is less so. The impacts are clear; the human, environmental, and economic connections are vivid. The changes are already under way. It is a local problem. It is our problem, not that of our children or grandchildren. We can cope with climate change on this little Island microcosm and protect our foundation — if we act soon.

In the book Climate Savvy, Adapting Conservation and Resource Management to a Changing World, authors Lara J. Hansen and Jennifer R. Hoffman make a subtle but vital point: “The prudent course is clearly to take action to limit vulnerability, but that is not always what we do when confronted with a challenge.”

To adapt to a vastly different future, to preserve that illusive value we call quality of life in this traditional fishing, farming, and resort community, we must take that first and most difficult step — acknowledge the problem. Then we can take a deep breath, seek inspired solutions for adapting to climate change in the short, medium and long term, and demand multi-disciplinary leadership. The sooner we act the less it will cost — in every imaginable and unimaginable way.

Liz Durkee is the conservation agent for the town of Oak Bluffs. This is the first part in an occasional series she is writing for the Gazette Commentary Page about climate change and what it means for the Vineyard.