The foundations of ecological science had yet to be formalized when John Muir wrote: “When we try to pick out anything by itself, we find it hitched to everything in the universe.” That often-quoted observation was a poetic way to describe the complex connectivity that is the essence of the science of ecology. Boundaries, like that between the land and the sea--the coastline--become blurred as connections between the ocean, the atmosphere, and ourselves grow increasingly apparent and troublesome. With human activities reaching a scale capable of altering both regional air quality and the global atmosphere, the ocean’s temperature and chemistry have also changed, with impacts on sea life and weather systems that feed back into the lives of people.

The coastal fringe is home to 53 percent of the United States’ population, a population density pattern that is found all over the planet. In California, 80 percent of us live within 30 miles of the Pacific. Where people concentrate in coastal areas, exhalations and emissions from their many daily activities are spread by regional and global winds, with consequences felt far inland. Smog, particulate pollution, and the greenhouse gases, carbon dioxide and methane, are all part of the mix that I suggest we call “people fumes,” so we can be realistic about the source of these problems. Individual daily acts like driving a car, innocuous in small numbers, turn into acts of pollution when multiplied by millions, simply because California’s coastal air basins are so densely populated. The scale of certain individual pollution sources has also become immense. The southern California port complex at San Pedro and Long Beach, for example, produces 25 percent of the south coast’s air pollution and is the largest stationary source of air pollution in California (see sidebar).

The atmosphere communicates with the seas about these troubling “people fumes.” Ocean and atmosphere work as a system with linkages that transport and exchange heat, water vapor, carbon dioxide, oxygen, and other gases. As human activities during the Industrial Age led to increased concentrations of greenhouse gases and atmospheric temperatures rose, the ocean dampened both types of increases by absorbing heat energy and carbon dioxide. Since the early 1800s, about half of the manmade releases of carbon dioxide have been captured by the oceans. But that has had increasingly severe consequences for the ocean and for global weather patterns.

Sea levels have risen four to eight inches during the past century, largely because of thermal expansion--warmer water occupying a greater volume--rather than as a result of melting glaciers and ice caps, as is commonly assumed. (Ice melt, if we push warming too far, will lead to more ominous sea level rises measured in feet, rather than inches.) The warming happens at the surface, yet slow mixing has been detected as much as 10,000 feet deep, so the entire ocean world is affected. More heat energy in the ocean, as well as in the atmosphere, generates more severe weather. In the last 20 years, researchers at the Scripps Institute of Oceanography, in San Diego, have documented trends of rising storm wave heights, higher incidence of extreme waves, and shorter El Niño cycles. Although an individual extreme-weather event like Hurricane Katrina cannot be absolutely tied to climate change, it is consistent with the patterns predicted by climate change theory and ocean-atmospheric models.

During El Niño years, wind and ocean currents flow west to east in the Pacific Ocean, and warm water collects off the eastern Pacific coast. Jet streams and storm tracks overhead shift accordingly. In between El Niño years, La Niña may appear, when a “cool pool” forms in the Pacific waters closest to us and the currents and wind turn around and flow away from the coast. With El Niño conditions, southern ocean species increase off the central and southern half of California, while northern species of zooplankton and northern cold-water fish decrease within local kelp forests. Green-spotted rockfish (Puffinus griseus) declined by half after the 1970s, while warm-water fish like Garibaldi (Hypsypops rubicundus) increased significantly.

This past winter, the cycle brought us La Niña, and we experienced the coolest winter since the last La Niña, in 2001. Yet the long-term warming trend continued. A National Climatic Data Center report released in March noted that “the combined global land and ocean surface temperature was the 16th-warmest on record for the December 2007-February 2008 period” (0.58¡F above the 20th-century mean). These changes have had profound effects on ocean life.

As carbon dioxide gas dissolves in water, it produces carbonic acid. Ocean water thus becomes more acidic and, coupled with warmer temperatures, kills coral reefs, leaving only bleached-looking white skeletons. Higher acidity also interferes with the formation of carbonate shells of mollusks and other creatures. We collect such shells on the beach, dimly aware that they originally housed living creatures. Microscopic phyto- and zooplankton that encase themselves in carbonate constructions are also damaged. Phytoplankton provide the photosynthetic base that begins ocean food chains, so they are critically important keystone species. Mess with their ability to survive, and the consequences could be widespread and profound.

All this should concern us, but it can be personally difficult to see the connections to ourselves and to grasp that our individual daily greenhouse gas emissions create problems for ocean species that must construct their bodies in sea water that is increasingly acidic because of higher atmospheric carbon dioxide levels.

A warmer atmosphere is also more energetic, and that affects wind patterns. Wind is one key to the California Current, which carries ocean water from north to south, down the coasts of Washington, Oregon, and northern California. As the rotating earth spins the shoreline eastward, away from that current, the water moves away from the coast. Nearshore surface water is then replaced from the depths (upwelling), and that brings upward nutrients that fertilize phytoplankton. The result has been a highly productive life zone off our coast as the increased productivity passed up the food chain. But the warmer climate is causing troubling changes to the beneficial upwelling process. Scientists report that stronger and more persistent winds, linked to global warming, are promoting more upwelling and for longer periods. The result in recent years has been too much of a good thing: massive phytoplankton production, way more than can be consumed by feeding animals. When that plankton floating near the ocean surface dies, it sinks to the ocean floor and decomposes. Decomposition sucks oxygen from the water, resulting in dead zones.

A study by the Partnership for Interdisciplinary Studies of Coastal Oceans, published in Science in February, found oxygen levels much lower than in the previous 50 years during each of the last six summers off the coast of Washington, Oregon, and parts of northern California. In 2006, the study found nearly complete mortality among sea floor creatures such as crabs, which could not escape the dead zones. Finding no correlation with other ocean temperature variables such as El Niño cycles, the study pointed to climate change as the driving force. What was a beneficial, life-sustaining process, in the right balance, has been thrown off balance, with deadly consequences.

There are messages in these events that Californians need to appreciate: It really is possible to have too much of a good thing; more is not always better.

Just as it is hard to connect damaged mollusk shells and acidic ocean water with our individual greenhouse gas emissions, it is difficult to appreciate our complicity in these ocean dead zone events. Yet, the atmospheric changes affecting the ocean can be traced back to “people fumes,” and that means you and me, our cars, houses, office buildings, factories, and ports.

Southern California’s port complex at San Pedro and neighboring Long Beach serves over 3,000 vessels each year. It is the third-largest port complex in the world, and (why is this not a surprise?) both the ports have plans for massive expansion.

Cargo ships burn dirty, high-sulfur diesel fuel, an asphalt-like material that generates 1,800 times as many particulates as does the fuel for diesel trucks, including ultra-fine particulates that are considered especially serious health hazards. Emissions from ocean vessels have gone almost unregulated, primarily because 90 percent of the ships using U.S. ports sail into them under foreign flags. United Nations efforts to reduce emissions from vessels have dragged on for years without resolution.

Once vessels enter our territorial waters, however, we have authority to require cleaner practices. Recent local, state, and federal measures are finally having some impact. In February, Congressional hearings considered proposed legislation introduced by California Senator Barbara Boxer that would require ships entering U.S. ports to burn cleaner fuels. During those hearings, a southern California emergency room physician called the San Pedro/Long Beach port region a “diesel death zone.” Ultra-fine particulates slip past the mucus and cilia defenses of our respiratory systems and lodge deep in the lungs. There they interfere with air-blood gas exchange, reducing lung efficiency with grim consequences: asthma, cardiac problems, and early deaths. The California Air Resources Board calculates that movement of goods is responsible for 2,400 premature deaths every year.

Hundreds of thousands of people live near the southern California ports, as well as near the state’s third-largest port, Oakland. They are, of course, most immediately affected, but the aerial effects from shipping are not limited to the immediate vicinity of the ports. The Santa Barbara County Air Pollution Control District estimates that ship emissions blowing onshore have essentially negated all the gains they have made by controlling emissions from cars and trucks, despite the fact that Santa Barbara has no commercial port and that container vessels travel 10 to 15 miles offshore.

Ships are not the only source of air pollution in ports. Cargo is transferred by diesel-powered loaders and forklifts onto thousands of diesel-powered trucks or to trains with diesel engines. Efforts have begun to provide electrical hookups so ships can use electric motors in place of their diesel auxiliary engines while in port and also to require cleaner-burning fuels in trucks and trains. But such efforts have proceeded too slowly for many port neighbors and the environmental groups that represent their interests.

When the Coalition for a Safe Environment and the Natural Resources Defense Council threatened to file a federal lawsuit this winter because of slow implementation of plans by the Long Beach port to reduce diesel particulate emissions, attorneys for the two organizations provided some pungent quotations: “Goods movement in California is responsible for more deaths every year than homicides. In view of that, ‘trying hard’ is just not enough.” They also pointed out that “Long Beach Mayor Bob Foster has said many times that it is not right to have the children of Long Beach pay with their health so that people in the Midwest can buy cheap TVs from Asia.”

So, Mr. Muir, your observation that everything is hitched together seems increasingly accurate and relevant. Though I live hundreds of miles inland, my purchasing decisions have consequences for people residing near the places where those overseas goods made their California landfall. The 21st-century global economy impacts air quality and personal health for far too many people, but my concerns come full circle as I also consider the carbon footprint of those goods--the greenhouse gas emissions inevitably produced as manufactured items move across the oceans in ships burning fossil fuels. Even the books I’ve authored in recent years are printed in China, because that is the place for publishers to go for high-quality color imagery. I’m dismayed to realize the size of the carbon footprint and the climate and health impacts of these books, which are intended to improve environmental awareness of issues like water and air in California.

John Muir, you were correct, but the connections you described have consequences that go beyond anything you likely ever imagined. Comprehending that I am one of millions of people in this state and that there are billions more of us across the planet, I’ll keep trying to appreciate those connections hitching me to everything else in the universe.

David Carle’s books include three guides to understanding human influences on California’s ecology and natural resources, published by the University of California Press: Introduction to Water in California ( 2004), Introduction to Air in California (2006), and Introduction to Fire in California (2008). He was a State Parks ranger for 27 years.