A mixture of Acropora species scleractinic hard corals, growing on a coral reef in Gaafu Dhaalu atoll, Maldives

Palm plantation colonized by invasive Sodom apple plant (Calotropis procera), Sharaan Nature Reserve, AlUla, Medina Province, Saudi Arabia

Palm plantation colonized by invasive Sodom apple plant (Calotropis procera), Sharaan Nature Reserve, AlUla, Medina Province, Saudi Arabia

Underwater view of of the reef system at Half Moon Caye, UNESCO, Mesoamerican Barrier Reef, Belize

Adult fin whale (Balaenoptera physalus) carcass in Holmabukta off the northwest of the Svalbard Archipelago, Norway

Adult polar bear (Ursus maritimus) in Holmabukta on the northwest coast of Spitsbergen in the Svalbard Archipelago, Norway

A small group of introduced reindeer (Rangifer tarandus) before eradication in Stromness Bay, South Georgia, Polar Regions

Huge avalanche, near Tangnag, Khumbu region, Himalayas, Nepal, Asia

Northern rockhopper penguins (Eudyptes moseleyi) covered in spilled oil from the wreck of the MS Oliva, Nightingale island, Tristan da Cunha Group, South Atlantic Ocean

A drought is an extended period of months, or years, when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region.