The Crowded Pacific Ocean
Barry A. Klinger, 10 June 2026
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1. The Problem with Mapping the Pacific and Its Islands
Half the world consists of the Pacific Ocean, which I have always conceptualized as a vast ocean basically devoid of land.
This is only partially true. That is because it has many islands which are invisible if we do not look hard enough. In the map above, there is a broad ridge (shallower than 4 km) crossing the Southern Hemisphere, with a little spur at about 15oS that appears to reach up to less than 2 km depth. If we look closer at that region, we see much more going on.
These maps are constructed from gridded data with 1 arcmin resolution (about 1 mile) taken from NOAA’s ETOPO22 data set. In the map on the left, you can see one island that looks like two ellipses stuck together (at around longitude 150oW): that’s the famous tropical island of Tahiti. To its northwest is a group of several islands that includes the mythical-looking Bora-Bora.
Across the northeast corner of the map, there are a bunch of “islands” of shallow water. The map on the right zooms in to show that almost every one is an atoll, basically a seamount with a flattish top that is mostly just below the sea surface. Atolls are typically bordered by a ring of land which is so narrow it is barely resolved at 1 arcmin.
One degree of latitude is about 111 km (almost 70 mi), so we can see from the two maps that there are islands ranging in size from ten or so miles down to less than a mile. This is a central dilemma of displaying the islands of the Pacific. How do we show the Pacific – over 16,000 km wide at the equator – while also showing islands that are only a few miles wide?
The solution used here is to show coarse resolution and fine resolution at the same time. The fine resolution shows the outlines of land at 1 arcmin resolution, so that small islands appear as black specks. The coarse resolution shows the amount of land in any given ½ degree patch of ocean. Green smudges indicate 50 km wide regions where there is at least some land, with darker shading representing a greater total land surface.
I always thought of Tahiti as the quintessential South Pacific island, perhaps because it was made famous by Paul Gauguin. But what other islands are there? World War II histories tell of long battles in the Solomon Islands. Are there still islands with that name? What other island groups are there? Which are independent nations? To answer these questions, I include the political names of island groups, as well as the geographic name of individual islands or subgroups of islands.
2. A Map of Oceania
This map is designed so that, when the image is as small as 7 inches wide (the left or right half of a laptop screen), all political unit names are legible and the green-marked island chains are easily visible. A few of the larger islands, including New Caledonia, the Solomon Islands (now an independent country east of Papua New Guinea), Hawaii and Fiji are visible. When enlarged to full-screen, geographic names become easy to read and many more islands are clearly visible.
Aside from the Aleutians in the far north, most of the Pacific Islands are in the tropics, so the map only extends to 30o latitude. The map also excludes the far eastern Pacific, home to the Galapagos Islands and some other island groups close to the Americas. The islands shown here represent all those colonized by Polynesian people coming from Asia before the arrival of European sailors and are collectively referred to as Oceania.
The map shows that the tropical/subtropical Pacific is, in a sense, quite crowded with islands. This region is home to 11 independent nations and several territories with various statuses. It contains more than 10,000 islands with an area of about 100,000 square kilometers (Oceania, Britannica). In another sense, the Pacific remains empty. The Pacific area shown in the map is over 74 million square kilometers, or about 740 times as large as the combined land area of all the islands (not including Papua New Guinea, Indonesia, and other islands near the East Asian coast).
The most far-flung island nation is the Republic of Kirabati. Most of its inhabitants live in its western island chain, the Gilberts. In fact, in the Kirabati alphabet, “ti” is pronounced like an “s”, and so Kirabati – pronounced “Kirabas” – is the island version of the name given to the group by Europeans. Kirabati also includes the Line Islands, over 2000 km to the east, and the Phoenix Islands, a group of atolls south of the equator with barely any land above sea level.
3. Size Chart for Oceania
Another way to get insight into what these many islands are like is to look at population and area data. In the figure below, each rectangle represents a single Pacific nation or territory. The width of the rectangle shows the total population. Each rectangle’s height shows the average amount of land (square kilometers) that is occupied by 1000 people. I call it specific area, a, and it is related to the population density, D, by D=1000/a.
Thus, if the specific area is a=20 km2/(1000 people) – meaning, 1000 people fit in an area of 20 square kilometers – then the population density is D=1000\/20= 50 people/km2. For comparison, population densities in the US include 10 people/km2 for Nebraska, 45/km2 for Washington state, 100/km2 for California, 200 /km2 for Delaware, and almost 500/km2 for the most crowded state, New Jersey. Their specific areas are 100, 22, 10, 5, and 2 km2/1000 people, respectively.
Why not just show population density? Because if the width of the rectangle is population and the height is area per population, the area of the rectangle = (width) x (height) = (population) x (area/population) = area of the islands. So a glance at the figure tells us the total population of each territory, how crowded it is, and how much land area it takes up.
The territories are arranged semi-geographically, with places mostly north of the equator at the top, southern hemisphere lands at the bottom, west on the left and east on the right. We can see that most of the oceanic population lives in the western Southern Hemisphere. The largest of these have hundreds of thousands of people each. The one place with a lot of people outside the Southwest Pacific is Hawaii, with almost 1.5 million. The least populated nations and dependent territories are in the Northwest, which here does not include the near-Asia island chains stretching from Japan to Papua New Guinea. A few of the island chains have so few people that their rectangles have negligible width on the graph. In order to make these visible, the figure includes a thick “base” near the zero of the population, darkened color and width independent of population. Thus readers can see Nieue and Bonin Islands even though their populations – under 5000 people in each case – are tiny.
All the regions with populations of at least 200,000 have moderate specific areas of 10 to 60 km2/1000 people. Across Oceania, most people on relatively large islands that are not particularly crowded. A few have much less space per person, such as around 3 km2/1000 people for Guam. This is comparable to Japan and the Philippines but not as crowded as Taiwan (1.5 km2/1000 people).
4. Crowded or Not?
Looking at the part of the Pacific equatorward of 30o latitude and between the near-Asian island chains and 255oE (105oW), the Pacific is quite uncrowded in terms of how much is covered in land – less than one fifth of one percent. It is much more crowded in how many small islands are scattered across the ocean. With a few exceptions, the islands themselves are not terribly crowded with people, with most nations and territories having densities comparable to many US states.
Last modified: 10 June 2026