Resource: Samoa Under Threat

Print Background Essay

Much of the world is experiencing the undeniable effects of global warming. These effects are reshaping the landscape, altering the web of life, and in some cases, displacing entire communities. For example, as sea ice melts more extensively in the Arctic, it exposes coastal villages to severe erosion. With less ice reflecting sunlight away, a positive feedback loop further accelerates warming. The impacts of this melting are already being felt far away from the poles.

While surface temperatures may not be rising as quickly in tropical regions as in polar ones, low-lying islands near the Equator, including those that comprise American Samoa, are dealing with an important consequence of a warming atmosphere: sea-level rise. Melting continental ice produces an influx of water to the oceans. This by itself causes sea level to rise incrementally. As the atmosphere warms due to the increase in heat-trapping greenhouse gases, so does the ocean. Because adding heat causes water to expand, sea level rises even more. According to the UN's International Panel on Climate Change (IPCC), this natural phenomenon, called thermal expansion, will contribute more to sea-level rise this century than any other environmental factor.

Some climatologists such as Penehuru Lefale think that changing conditions possibly brought on by global warming may also be causing more frequent and intense storms. They argue that higher sea surface temperatures and water levels are producing larger storm surges than in years past. A storm surge is formed when the swirling winds of a tropical cyclone pile up ocean water around the eye of the storm in a dome shape. As the storm nears the land, the shallower seafloor blocks the retreat of water, and the water surges on land. Storm surges produce dangerous flooding, which destroys buildings and causes drowning.

Sea-level rise is also increasing coastal and inland erosion. This poses a further threat to Native villages and essential infrastructure, including roadways and airports. While there is no clear trend in data to confirm the climatologists' assertions, researchers continue to investigate a link between global warming and tropical storm frequency and intensity.

Despite being responsible for just 0.03 percent of the world's carbon dioxide emissions, Pacific island nations will be among the first human casualties of global warming. According to at least one government forecast, sea level in the Asia-Pacific region could rise as much as 48 centimeters (19 inches) beyond current levels by 2070. With about a third of the world's population living within 100 meters (325 feet) of an ocean coastline, on land that lies at or only slightly above present sea level, sea-level rise is justifiably a major concern.

To learn more about the relationship between ice and global temperature, check out Earth System: Ice and Global Warming, Antarctic Ice: Sea Level Change, and Mountain of Ice: If the Ice Melts.

To learn about the influence of snow cover on atmospheric temperatures, check out Earth’s Albedo and Global Warming.

To learn more about the effects of global warming on ecosystems, check out How the Arctic Ecosystem Might Change.

To learn more about the atmospheric conditions that trigger tropical storms, check out How Hurricanes Form.

Print Questions for Discussion

• What is the main climate-related problem faced by Samoa and other Pacific island countries, according to the climatologist in the video?
• What evidence does the narrator use to back up his statement that a trend has emerged toward an increase in cyclones and tropical storms in Samoa?
• Can you make any general statements about the populations that are currently most at risk because of global warming?
• What options do the Samoan and Alaska Native peoples have to deal with global warming?