Taiwan is a medium-sized archipelago in East Asia, located at 23°30N, 121°00E and running through the middle of the Tropic of Cancer (23°5N). It makes up the majority of the territories effectively under the administration of the Republic of China (commonly known as "Taiwan").
The island of Taiwan was formed approximately 4 to 5 million years ago from a geosyncline (via plate tectonics), and is part of an island arc. It was formed when the Eurasian Plate slid under an ancient chain of volcanic islands on the neighboring Philippine Sea Plate. At the northern end of Taiwan, the Philippine Sea Plate slides under the Eurasian Plate.
The islands of Kinmen, Matsu, Wuchiu, etc. across the Taiwan Strait, and Pratas and Taiping in the South China Sea, are also administered by the Republic of China. These islands are however not part of the Taiwanese archipelago. Taiwan's area is 35,980 km² (13,892 mi²) of which 32,260 km² is land and 3,720 km² is territorial water claims, making it slightly smaller than the combined area of Maryland and Delaware, or slightly bigger than territory of Belgium. It is 394 km (244 miles) long and 144 km (89 miles) wide. It has a coastline of 1,566.3 km. The ROC claims an exclusive economic zone of 200 nautical miles (370 km) and a territorial sea of 12 nautical miles (22 km).
The climate on the island is generally marine and varies widely by season in the Northern part and the mountain areas. The South, however, belongs to the tropical belt and is warm and humid all year. From May to June it's rainy season, with almost daily showers. From July to October typhoons are most likely to strike, on average about four direct hits per year. In the northern part of Taiwan, cloudiness is persistent and extensive during the year; in the south, however, the rainy days are always in the summertime, and 90% of the annual precipitation falls during this period. The annual rainfall is usually more than 2500 mm, close to 5000 mm in some Eastern regions.
The terrain in Taiwan is divided into two parts: the flat to gently rolling plains in the west, where 90% of the population lives, and the mostly rugged forest-covered mountains in the eastern two-thirds. The highest elevation in Taiwan is Jade Mountain (Yu Shan), at 3951.798±0.072m in year 2003. .
The western mountain forests are very diverse, with several endemic species such as Formosan Cypress (Chamaecyparis formosensis) and Taiwan Fir (Abies kawakamii), while the Camphor Laurel (Cinnamomum camphora) was once also widespread at lower levels (now mostly cleared for agricultural land). Prior to major Taiwanese economic success, the mountainous areas held several endemic animal species and subspecies, such as the Swinhoe’s pheasant (Lophura swinhoii), Taiwan blue magpie (Urocissa caerulea), Formosan Black Bear (Selanarctos thibetanus formosanus), the Formosan Sika Deer (Cervus nippon taiwanensis or Cervus nippon taiouanus) and the Formosan landlocked salmon (Oncorhynchus masou formosanus). A few of these are now extinct, and many others have been designated endangered species.
Seven national parks in Taiwan showcase the diverse terrain, flora and fauna of the archipelago. Kenting National Park on the southern tip of Taiwan contains uplifted coral reefs, moist tropical forest and marine ecosystems. Yushan National Park has alpine terrain, mountain ecology, forest types that vary with altitude, and remains of ancient road. Yangmingshan National Park has volcanic geology, hot springs, waterfalls, and forest. Taroko National Park has marble canyon, cliff, and fold mountains. Shei-Pa National Park has alpine ecosystems, geological terrain, and valley streams. Kinmen National Park has lakes, wetlands, coastal topography, flora and fauna-shaped island. Dongsha Marine National Park has the Pratas reef atolls for integrity, a unique marine ecology, biodiversity, and is a key habitat for the marine resources of the South China Sea and Taiwan Strait.
Current environmental issues include: air pollution; water pollution from industrial emissions and raw sewage; contamination of drinking water supplies; and trade in endangered species. Though regulation of sulfate aerosol emissions from petroleum production is becoming stringent, acid rain remains to be a threat to the health of the residents and the forests. Scholars in Taiwan point out that more than half of its acid rain is actually brought by monsoon rains from mainland China.