Hypercane

A hypercane is a hypothetical class of extreme hurricane that could form if ocean temperatures reached around 50 °C (122 °F), which is 15 °C (27.0 °F) warmer than the warmest ocean temperature ever recorded. Such an increase could be caused by a large asteroid or comet impact, a large volcanic, supervolcanic eruption, or extensive global warming. There is some speculation that a series of hypercanes resulting from an impact by a large asteroid or comet contributed to the demise of the dinosaurs. The hypothesis was created by Kerry Emanuel of MIT who also coined the term.

Physical description

The relative sizes of Typhoon Tip, Cyclone Tracy, and the United States. Although it would be far more intense than Typhoon Tip, a hypercane wouldn't be larger in size than Cyclone Tracy, so it would remain very local but highly destructive.

In order to form a hypercane, according to Emanuel's hypothetical model, the ocean temperature would have to be 48°C (120°F). Although such a storm would also be quite small in area as compared to hurricanes, perhaps only 25km² (10 mi²), it would extend much further into the upper stratosphere; present day hurricanes only extend into the lower stratosphere.

Hypercanes would have wind speeds of over 800 km/h (500 mph), equalling an original Fujita scale rating number of F9.0, and would also have a central pressure of less than 70 kilopascals (21 inHg) (700 milibars), giving them an enormous lifespan. For comparison, the largest and most intense storm on record was 1979's Typhoon Tip, with a wind speed of over 300 kilometres per hour (190 mph) and central pressure of 87 kilopascals (26 inHg) (870 milibars). Such a storm would be eight times more powerful than the strongest storms yet recorded.

The extreme conditions needed to create a hypercane could conceivably produce a system up to the size of North America, creating storm surges of 18 m (59 ft) and an eye nearly 300 km (190 mi) across. The waters could remain hot enough for weeks, allowing more hypercanes to be formed. A hypercane's clouds would reach 30 km (19 mi) into the stratosphere. Such an intense storm would also damage the Earth's ozone. Water molecules in the stratosphere would react with ozone to accelerate decay into O₂ and reduce absorption of ultraviolet light.

In popular culture

Peter F. Hamilton's science-fiction trilogy The Night's Dawn Trilogy describes an Earth where, by the 24th century, runaway climate change has made hypercanes a common occurrence. In the context of the novels, hypercanes are referred to as armada storms. This label was created during the first recorded hypercane, as an extension of the famous chaos theory meme: if a butterfly can create a storm by flapping its wings, a hypercane can only be the consequence of an armada of butterflies working in unison. The anime television series Tactical Roar uses a fictional hypercane in the Pacific Ocean as a pretext to showcase naval battles, which are the series' focus, and a hypercane is also shown in the episode "The Storm" in Stargate: Atlantis. Hypercanes are also depicted, although somewhat differently, in the popular movie The Day After Tomorrow. Some young-earth creationists claim that hypercanes struck frequently in the years following the Great Flood.^{[citation needed]}