Earth has experienced five mass extinctions over its ~4.5 billion year history, with proposed causes ranging from extraterrestrial bolide impacts to massive flood volcanism. The fleeting time when human activities have significantly impacted the Earth system shows similarities with past episodes of mass extinctions. Current extinction rates are high, global environments are changing, the ocean is becoming more acidic and perhaps less oxygenated, and chemical pollution is widespread. Evidence suggests that a mass extinction, defined when Earth loses more than 75% of its total estimated species in a geologically short interval, may now be underway, driven by Homo sapiens.

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Marine geophysicist Mike Coffin investigates interactions between the oceanic environment and the solid Earth. After growing up in Bangor, he was educated at Dartmouth College (AB) and Columbia University (MA, MPhil, PhD). Ever since, he has pursued an international career that reflects the boundless nature of the global ocean. He has worked in Australia (1985-1989; 2011-present), the US (1990-2001), Japan (2001-2007), and the UK (2008-2010). He has also held visiting positions in the US (1982, 2002, 2016-present), Norway (1992, 1996), Australia (2000), and France (2001). Mike has led or participated in 37 blue-water research expeditions totaling  more than 1,000 days at sea, focused mainly in the Southern, Pacific, and Indian oceans.