Sir Ian Lamont Boyd, FRSE, FRSB, FRS (born 9 February 1957) is a Scottish zoologist, environmental and polar scientist, former Chief Scientific Adviser at the Department for Environment, Food and Rural Affairs (DEFRA)[2] and is a professor of biology at the University of St Andrews.

He is currently Professor in Biology at the University of St Andrews and was Chief Scientific Adviser to the Department for Environment, Food and Rural Affairs (Defra) from 2012 to 2019.

In parallel to his formal positions he has chaired, co-chaired or directed international scientific assessments; his activities focusing upon the management of human impacts on the environment.

He explained in a blog[7] that Defra "is responsible for delivering the basics of life – food, water and air – in sufficient quantities and to a demanding quality standard.

As a consequence, we have to deal with some of the most difficult questions facing people and the planet" and that "like many others, I cannot easily walk away from these challenges and especially when opportunities are opening up which could ratchet us along the track to improvement."

Defra was originally formed from the Ministry for Agriculture, Fisheries and Food and part of the Department for the Environment, Transport and the Regions both of which had Chief Scientific Advisers up until the merger.

His appointment was non-political, but he served as scientific adviser to four different Secretaries of State including Owen Paterson, Liz Truss, Andrea Leadsom and Michael Gove.

Ian Boyd has published over 180 peer reviewed scientific papers (H-index 82), 14 books and has been the author/co-author/editor of several major reports including a marine atlas of Scotland's coastal seas.

[11] His most significant discovery has been the functional relationship between the performance of marine predators and the state of their food supply, first published in a paper in the Journal of Animal Ecology in 2001.

They published a paper in the journal Science[13] making the point that fisheries needed to leave at least one-third of the biomass in the ocean for other predators like seabirds.

[29][30] Together with his father, John Morton Boyd, he has written several books about the natural history of the Hebrides include one published in the Collins New Naturalist series.

[35] In 2015, he wrote an oped in the New York Times titled "Our deadened, carbon soaked seas"[36] with Rick Spinrad who was then the Chief Scientist at NOAA to draw attention to the dangers of ocean acidification.

Until 2023, the trust owns the Treshnish Isleas in the Hebrides and has renovated the Skerryvore lighthouse supply station at Hynish on the island of Tiree to create an outdoor centre, holiday accommodation and affordable housing.

"[46] The sentiment is seen as controversial by such people as Naomi Klein[47] and George Monbiot, the latter of which described the opinion as "Shut up, speak through me, don't dissent – or your behaviour will ensure that science becomes irrelevant.

He led the Sea Mammal Research Unit at the University of St Andrews to the award of the Queen's Anniversary Prize in 2011.