West Africa or Western Africa is the westernmost region of Africa. The United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, and Togo, as well as Saint Helena, Ascension and Tristan da Cunha (United Kingdom Overseas Territory). The population of West Africa is estimated at 419 million people as of 2021, and at 381,981,000 as of 2017, of which 189,672,000 were female and 192,309,000 male. The region is demographically and economically one of the fastest growing on the African continent. West Africa has a rich ecology, with strong biodiversity and several distinct regions. The area's climate and ecology are heavily influenced by the dry Sahara to the north and east, which provides dry winds during the Harmattan, as well as the Atlantic Ocean to the south and west, which provides seasonal monsoons. This mixture of climates gives West Africa a rich array of biomes, from biodiversity-rich tropical forests to drylands supporting rare and endangered fauna such as pangolins, rhinoceros, and elephants. Because of the pressure for economic development, many of these ecologies are threatened by processes like deforestation, biodiversity loss, overfishing, pollution from mining, plastics and other industries, and extreme changes resulting from climate change in West Africa.