Territory of Guam

Territory of Guam

Geographically part of the Mariana Archipelago, Guam shares an ancient history and culture with the other islands in the chain. The archipelago was settled approximately 4,000 years ago by the Chamorro people, who maintained a culture and language that is unique throughout the Pacific. Guam and the Mariana Islands were among the first islands sited by European explorers, by Spanish explorer Ferdinand Magellan in 1521. The island chain has been colonized ever since, by a succession of colonial powers, including Spain for over two hundred years. However, Guam’s political and colonial history diverged from the rest of the Mariana Islands in 1898 after the Spanish-American War, when Spain ceded Guam to the United States, and sold the remainder of the Mariana Islands to Germany. After experiencing major battles and extreme violence under Japanese occupation during World War II, Guam officially became a U.S. territory in 1950. Under the Guam Organic Act, Guamanians are represented in Congress by a nonvoting member, and are U.S. citizens but cannot vote. Guam has become the commercial and population hub of the Micronesian region, and is by far the most developed island in the area. Because it is a high island, Guam has extensive freshwater resources, and is not threatened by sea-level rise like the low atoll nations in the region. However, Guam lies directly within the typhoon belt, and is regularly hit by major storms and typhoons [9]. On December 8, 2002, Supertyphoon Pongsona produced strong wind gusts peaking at 278 km/h (173 mph), which left the entire island of Guam without power and destroyed about 1,300 houses. Damage on the island totaled over $700 million (2002 USD, $800 million 2007 USD) and was considered by the Federal Emergency Management Agency (FEMA) to be the costliest United States disaster in 2002 in a single state or territory [3, 7].

Geography

The island of Guam is the largest and southernmost island in the Marianas archipelago, which continues northward from Guam and makes up the Commonwealth of the Northern Mariana Islands. At 212 sq miles (549 sq km), it is the largest island in Micronesia. The capital, Hagåtña (formerly Agana), is located on the west coast, near the middle of the island, and is the seat of government and the site of the main commercial districts on Guam [10]. The northern part of the island is a forested coralline limestone plateau with sheer coastal cliffs, while the south contains volcanic peaks covered in forest and grassland. A coral reef surrounds most of the island, except in areas where bays exist that provide access to small rivers and streams that run down from the hills into the Pacific Ocean and Philippine Sea [1, 9]. The Northern Guam Lens provides nearly 40 million gallons per day of drinking water (about 80 percent of the total) to the island of Guam [8]. Guam is the closest landmass to the Mariana Trench, the deepest point in the ocean [9]. Because of its strategic location in the western North Pacific Ocean, the U.S. has long maintained military bases there [1].

Climate

Guam’s climate is almost uniformly warm and humid throughout the year. Generally, the temperature range is from the low 70s to the middle 80s Fahrenheit. The coolest and least humid months, marked by prevailing westerly tradewinds, are in December through February.  Although the warmest months are from March through August, the tradewinds still blow steadily from the east or northeast. There are two seasons, the dry and the rainy. The dry season typically begins in December and extends through June.  The rainy season falls within the remaining months [4]. The annual rainfall totals 80-110 inches (2,032-2,794 mm) [4].  Three-quarters of the rain falls between during the rainy season between June and December [6]. During the rainy season there is a breakdown of the trades, and on some days the weather may be dominated by westerly-moving storm systems that bring heavy showers, or steady and sometimes torrential rain [5]. Guam lies within the typhoon belt and is periodically struck by tropical storms and typhoons [6], which are most frequent from June through December.  An average of three tropical storms and one typhoon pass within 180 nautical miles (330 km) of Guam each year. Since 1962, ten of thirteen major disaster declarations resulted from typhoons, and two of the other disasters were associated with climate [2]. The most intense typhoon to pass over Guam recently was Super Typhoon Pongsona on December 8, 2002, with sustained winds of 125 miles per hour, leaving massive destruction as the oil tanks in Apra Harbor caught fire [1, 2].  The loss of harbor operations made response to the disaster more difficult [2].

Key climate change issues affecting Guam include threats to human health, risks to freshwater resources, increasing wildfire, and the potential for damage to infrastructure caused by future sea level rise and stronger typhoons. Climate change is expected to disrupt many aspects of life in Guam. Those who are already vulnerable are harmed more than others by extreme weather and climate shifts. For a comprehensive summary of the climate trends and future projections, and how climate change is affecting Guam’s key sectors, see Climate Change in Guam: Indicators and Considerations for Key Sectors (November 2020). Authors from the University of Guam and the East-West Center—along with more than 30 technical contributors from local governments, NGOs, researchers, and community groups—collaboratively developed the Guam PIRCA report. Climate Change in Guam is one in a series of PIRCA reports aimed at assessing the state of knowledge about climate change indicators, impacts, and adaptive capacity of the US-Affiliated Pacific Islands and the Hawaiian archipelago.