Sub-aerial and submarine volcanic eruptions and climatic variability Wyss Yim Department of Earth Sciences, The University of Hong Kong / Institute of Space and Earth Information Science, Chinese University of Hong Kong / Association for Geoconservation, Hong Kong Presentation at the London Climate Change Conference, Conway Hall on September 8-9, 2016

Plan Introduction Case study of a sub-aerial eruption Case study of a submarine/sub- aerial eruption (4) Conclusions

Why study present day volcanic eruptions? Eyjafjallajökull (E-15) April 14, 2010 eruption Effect – Slovakia wettest year since 1881 Most reliable record – Information age Applications – Farming/climatic variability ( Meteorological observations ( Satellite observations since ~1980 ( Weather disaster media reports ( Aviation safety

Volcanic Explosivity Index (VEI) Above VEI 2 regional impacts on weather/climate may already be detectable Estimation of explosiveness of sub-aerial volcanic eruptions (Newhall and Self 1982) Acidic magma most explosive 8

1958-1994 solar radiation record from Mauna Loa Why I am interested in volcanic eruptions? Agung 1963 VEI 4 Comparison Pinatubo 1991 VEI 6 El Chichón 1982 VEI 4 VEI – Volcanic explosivity index

Hong Kong’s rainfall record during the 3 volcanic eruptions Agung 1963 VEI 4 Driest year on record Comparison Pinatubo 1991 VEI 6 11th driest on record El Chichón 1982 VEI 4 2nd wettest on record VEI – Volcanic explosivity index

Classification of volcanic eruptions – (1) Sub-aerial / land - switches on hot air followed by cooling (atmospheric warming, injection of ash, gases and aerosols, blockage of shortwave radiation, pressure changes, moisture redistribution, continental cooling, ozone depletion, circulation changes, severe weather) (2) Submarine / sea floor switches on hot seawater (cause of sea-surface temperature anomalies, pressure changes, ocean and air circulation changes, moisture redistribution, continental warming, severe weather events including cyclones) (3) Mixed - initially submarine later sub-aerial (combination of 1 and 2).

↑ → ← Sub-aerial model Thermal plume Eruption changes normal air circulation / creats clouds / destroys O3 ↑ Ash & aerosols reduces solar radiation leading to cooling SO2, HCl & H2O Warm air stores more moisture – water vapour redistribution Air pressure changes (low) Cool air stores less moisture → ← Cooler air Impact longer lasting if major El Chichón, Mexico 1982 USGS

June 15, 1991 Pinatubo eruption VEI 6

Track of Yunya (Oswalt et al. 1999) Day of eruption Two days before

↓ Why 1991 was a global drought year? Pinatubo eruption cloud Typhoon Yunya Why 1991 was a global drought year? Water vapour transfer into the stratosphere creating atmospheric rivers

Pinatubo eruption cloud maximum elevation 55 km Oswalt et al. (1999)

Space shuttle photo over South America taken on August 8, 1991, showing double layer of Pinatubo aerosol cloud (dark streaks) above high cumulonimbus tops Global temperature drop of ~0.5o C NASA

Submarine model* * Initially submarine later sub-aerial, basaltic magma hotter Examples studied – El Hierro, Canary Islands 10/2011-3/2012 Hunga, Tonga* 12/2014-1/2015 Nishinoshima, Japan* 11/2013-8/2015 Action – Switching on of hot seawater causing ocean and air circulation changes El Hierro NASA

Nishinoshima submarine/sub-aerial eruption 940 km south of Tokyo November 2013 to August 2015 (Wikipedia) Image on November 13, 2013: Japan Coast Guard Image on December 8, 2013: NASA

Sea-surface temperature anomalies showing the North Pacific Blob on January 2, 2014 Nishinoshima eruption 11/2013-8/2015 Blob

Observations connecting Nishinoshima with the Blob __________________________________________________________________________________________________________ Date Eruption activity Northern Pacific Blob __________________________________________________________________________________________________________ November Submarine eruption created new island Initial Blob 800 km wide and 91 m deep 2013 December Island area reached 5.6 km2 and ~25 m - 2013 above sea level February - Temperature was ~2.5oC above normal 2014 June 2014 - Name Blob was coined by Nicholas Bond Size reached 1600 km x 1600 km and 91 m deep Spread to the coast of North America with patches off Alaska, Victoria/California and Mexico December Island now ~2.3 km in diameter and ~110 m Year without winter in western North America coast 2014 above sea level and first mass bleaching of Hawaiian coral reefs January- Episodic eruption with lava flows - August 2015 Early - Blob persisted and ended 2016 Source: Wikipedia Date

The Blob separated into three parts on September 1, 2014 Warm water build up in slack areas of gyres 2 3 Ocean circulation

Contraction of Arctic sea ice Expansion of Antarctic sea ice Impact of the Blob on September 1, 2014 - nature’s way of neutralizing hot and cold Contraction of Arctic sea ice 1 2 3 Expansion of Antarctic sea ice

Sea-surface temperature anomalies on June 29, 2015 after the Wolf eruption ended 5-6/2015 with lava flow entering the ocean

Establishment of the strong 2015 El Niño August 31, 2015

Main conclusions (1) Sub-aerial and submarine volcanic eruptions are underestimated natural causes of climatic variability. (2) Volcanic eruptions may be the cause of air and ocean circulation changes, extreme weather events, and polar sea ice changes. (3) The release of volcanic aerosols including water vapour into the atmosphere is important in regional/global climatic variability. (4) Possible contributors to the strong 2015 El Niño year include the Nishinoshima eruption during November 2013 to August 2015, the Hunga eruption during December 2014 to January 2015 and the Wolf eruption during May to June 2015. (5) Volcanic eruptions are a timely reminder of Earth systems science geoethics. Acknowledgements Thanks are due to the records available including NASA, NOAA and Wikipedia.

Thank you Volcanic eruptions – A natural experiment to learn from NASA May 23, 2006 Cleveland, Aleutian islands Thank you