The Changing Landscape of Oceania

The human settlement of Oceania, from the earliest migrations to European colonization, has reshaped the physical landscape of this region. Environmental degradation and disturbances to resources like air, land, and water are serious concerns, as economic growth often comes at the expense of environmental sustainability. In Australia, for example, wide stretches of previously sparsely inhabited Outback have become grazing lands. In Papua New Guinea, illegal logging has contributed to significant deforestation. Pollution from dairying in New Zealand has led to high water pollution levels.

Invasive species have also had significant environmental impacts in a region that has been otherwise relatively isolated. Australia has strict quarantine laws to limit damage from nonnative plants and animals. The country currently spends around $4 billion yearly on invasive weed management alone. Cats have been banned in parts of New Zealand, where they pose a threat to local bird species. Rats brought by early European ships have presented a significant problem for many islands of the Pacific, where they kill other plants and animals and also spread disease. Offshore, invasive fish and algae species have damaged fragile ocean ecosystems.

In addition to local pollution concerns, human settlement in other world regions has contributed to pollution in the Pacific Ocean. Worldwide, there are five main ocean gyres, large systems of rotating ocean currents (see Figure 10.12). In the northern Pacific Ocean, one gyre has very high concentrations of trash and plastics carried to the area by ocean currents. It has been termed the Great Pacific garbage patch. When you throw something "away" improperly, these gyres are really where "away" is. A water bottle improperly disposed of on the western coast of North America will make its way to the Great Pacific garbage patch in around six years.

Figure 10.12 Ocean Gyres and Currents (Derivative work from original by Ingwik, Public Domain)

One issue with plastics is that they do not biodegrade; instead, they keep breaking down into smaller pieces while still remaining plastic. Fish and other marine life eat these tiny bits of plastic, which can disrupt a number of biological systems. Humans then consume some of these fish species. Because the Great Pacific garbage patch contains such small pieces of plastic, and most of the plastic is below the ocean's surface, it is not easily visible to the naked eye, and it is difficult to estimate its size. Some have theorized the patch is as big as or bigger than the U.S. state of Texas, while others note that the idea of a "patch" of garbage is really a misnomer as there are concentrations of trash throughout the world's oceans.

Trash from other world regions also washes up along the shores of the Pacific islands. Kamilo Beach in Hawaii is the site of a significant amount of plastic that has washed ashore from the Great Pacific garbage patch, so much so that the area has been nicknamed "Plastic Beach" (see Figure 10.13). Though the shoreline looks sandy, 90 percent of it is actually bits of plastic, and you would have to dig down at least one foot to reach grains of sand. Plastic trash litters many of the shorelines of the Pacific islands, presenting a hazard to marine life and a management and cleanup challenge since debris often comes from thousands of miles away.

Figure 10.13 Plastic Debris on Kamilo Beach, Hawaii (Algalita.org, Public Domain)

However, changes in the global climate pose the most severe environmental threat to Oceania. For many of the world's regions, climate changes are viewed as hypothetical. Hurricanes might increase in intensity. The risk of fire might increase. Changes in bird migrations in Europe and North America to shifts in global fish stocks have already been linked to increases in global temperature but with little direct effect on the human populations of these regions. In Oceania, though, small increases in temperature and ocean levels could have disastrous effects on already fragile ecosystems and economies.

The Great Barrier Reef is currently experiencing periods of coral bleaching due to increasing ocean temperatures. When waters get too warm, coral experience "stress" and expel the colorful, algae-like organisms that live within them. Mass coral bleaching has occurred several times since the late 1990s and is expected to become a regular occurrence as ocean temperatures continue to rise. Coral bleaching has also been documented in other reefs, including those in Hawaii.

Some of the leaders of the Pacific islands have been among the most vocal champions for global climate regulations. In 2015, the prime minister of Fiji, Frank Bainimarama, did not mince words: "Unless the world acts decisively in the coming weeks to begin addressing the greatest challenge of our age, then the Pacific, as we know it, is doomed." Fiji has experienced increased infectious diseases related to higher temperatures and record-breaking high tides and has had to relocate citizens due to rising ocean levels.

Many of the effects of warming temperatures in the Pacific relate to changes first being documented in the Arctic. Scientists have consistently documented the melting of Arctic sea ice for the past decade (see Figure 10.14). As the ice sheets melt, raising global sea levels, the surface becomes less reflective. It absorbs more of the sun's rays, further accelerating warming and beginning a cycle that could be difficult to undo. The North and South Poles have experienced faster warming than the rest of the world, and some areas of the Arctic have seen an increase in temperature by 3 to 4 °C (5.4 to 7.2 °F).

Figure 10.14 Minimum Extent of Arctic Sea Ice, 1984 and 2012 (Derivative work from original by Jesse Allen, NASA Earth Observatory, Public Domain)

The rising oceans in the Pacific and the concentrations of pollution in this region are stark reminders of our interconnected world. Fossil fuel emissions from cars in the United States affect the amount of greenhouse gases in the atmosphere, which can increase global temperatures and melt ice in the Arctic. A plastic shopping bag discarded improperly in Japan makes its way out to sea, breaking down and forming a coat of plastic sand on a Pacific island. But this same interconnectedness could perhaps be used to our advantage. Small, individual changes magnified across the global system could have profoundly positive effects. In many ways, the future of Oceania will be decided by the actions of global citizens and leaders.

Source: Caitlin Finlayson, https://worldgeo.pressbooks.com/chapter/oceania/#chapter-359-section-5
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