By Prof. James Renwick, VUW School of Geography and Environment and Earth Sciences [May 2018]
The roster of Scottish scientists, researchers and explorers who have contributed to climate research is far too long to cover in a single essay or presentation. Here, I touch on the lives and works of five eminent Scots who made crucial contributions to climate science over the past few centuries.
The story starts with Joseph Black (1728-1799), the discoverer of carbon dioxide. Black was a prominent member of the “Enlightenment” in Britain, contemporary of James Watt, Erasmus Darwin, and Josiah Wedgewood. He was there at the beginning of the Industrial Revolution, helping Watt improve the efficiency of his steam engines, and along the way helping to found the science of thermodynamics. He established the concept of “latent heat”, the energy it takes to change ice to water and water to vapour. The absorption and release of latent heat turns out to be a very important way for the atmosphere to move heat around and regulate the climate of planet earth. For climate change research though, carbon dioxide is even more important. It is very good at absorbing the heat the earth radiates towards space, and it stays in the air for centuries, making it the most important “greenhouse gas” in the long run. Most of the carbon dioxide Watt’s coal-burning machines released in the 1750s is still in the atmosphere, warming us. Carbon dioxide in the air has increased nearly 50% since Black’s time, the highest level it has been for millions of years.
Jumping forward a century or so, James Croll (1821-1890) helped advance our understanding of why ice ages happen. In the mid-19th century, the puzzle of the ice ages was one of the big science questions of the day, leading to understanding of how changes in greenhouse gases in sunlight can warm or cool the earth. Croll was self-taught, but quickly increased his understanding and was soon corresponding regularly with Darwin and other leading scientists. Croll realised that changes in the shape (“eccentricity”) of the earth’s orbit could change the amount of sunlight falling on the earth and over thousands of years could lead to expansion of the ice sheets and eventually to an “ice age”. He was right, but didn’t know that other slow changes, in the tilt of the earth’s axis and in the wobble of the earth as it spins on its axis, also contribute to the effect he identified. That led to him getting the timing of the last ice age wildly wrong, even though he had the right idea. Subsequently, Milutin Milanković (a Serbian, not a Scot) synthesised all the relevant astronomical effects and came up with the ice age theory we use today (called “Milanković cycles”).
Living at roughly the same time as James Croll, Alexander Buchan (1829-1907) was an early champion of the use of weather maps for forecasting, building on the work of Robert Fitzroy (former Governor of New Zealand and captain of Darwin’s “Beagle”). He established the Ben Nevis observatory and served as the Secretary of the Scottish Meteorological Society for 47 years (worth a medal in itself, I’d say). He was a strong supporter of the Challenger Expedition (1872-76), a British enterprise led by Scottish marine biologist Charles Thomson, and credited with founding the science of oceanography. The expedition covered 130,000km, retrieved 5,000 new species, and came close to Antarctica but did not sight land. The Challenger visited Wellington in 1874, shortly before discovering the Challenger Deep in the tropical Pacific Ocean. Alexander Buchan provided meteorological advice to the expedition and helped collate the numerous meteorological and oceanographic observations made throughout the voyage.
John Aitken (1839-1919) again was a contemporary of Buchan and Croll, but studied clouds and dust rather than ice ages and oceans. Aitken studied under Lord Kelvin and worked at first as a marine engineer, but maintained an interest in the atmosphere and in meteorology. He used his engineering skills to make many advanced instruments, including the “koniscope” to measure atmospheric dust particles. Aitken realised that cloud droplets must form onto something, the water does not just condense out of thin air. Thus, the presence of particles in the air is critical to the existence of clouds, and the cycle of latent heat. Today, the “Aitken nucleus” is the name given to the smallest atmospheric particles, in honour of the work of John Aitken in the 19th century. In his later years, Aitken studied storms, weather, glaciers, and how best to make meteorological measurements. He was a very humble person but a brilliant scientist and engineer/instrument-maker.
One of the most prominent figures in early earth science research was William Speirs Bruce (1867-1921). Bruce was a key player in the great age of discovery, travelling to Antarctica at the same time as Shackleton and Scott. Yet, he is barely remembered today, and was largely forgotten by the 1920s. The reason seems to be his difficult nature: he was a fervent Scottish nationalist and was described by a friend to be “as prickly as the Scottish thistle itself.” He made a number of powerful enemies and did not ingratiate himself with patrons and sponsors nearly as well as his English contemporaries. Nevertheless, the Scottish National Antarctic Expedition (SNAE), led by Bruce during 1902-04, was one of the most successful voyages of its day to the Antarctic continent. Unable to persuade the President of the Royal Geographical Society (RGS) to let him go on Scott’s Discovery voyage, Bruce organised and ran the SNAE in “competition” with the RGS-sponsored voyage led by Scott. This did not go down well, and Bruce was never awarded the Polar Medal of the RGS, even though he received personal congratulations from the King (Edward VII).
Bruce was arguably the most accomplished polar explorer in Britain at the turn of the 20th century, having spent considerable time in the Arctic, befriending Fritdjof Nansen along the way. He also spent time at the Ben Nevis observatory, which often experienced sub-polar conditions, and studied the findings of the Challenger expedition. His ship, the “Scotia” sailed the length of the Atlantic Ocean for the SNAE, entering the Weddell Sea twice. The all-Scots crew made it to 74°S and sighted (and named) the coast of “Coats Land”, named after expedition sponsors the Coats family of cotton-reel fame. The SNAE established a meteorological station and small observatory in the South Orkney islands, the management of which was taken over by the Argentine government and which is still open – the longest-running weather station in the Antarctic region.
The Scottish contribution to climate change and earth science research is still going strong today. Some of the leading researchers active in Scotland today include David Sugden (geology of the West Antarctic), Gabi Hegerl (climate dynamics and climate change), Sandy Tudhope (the past climate of the tropics), and Simon Tett (climate dynamics and ice-climate interactions). One of Simon’s Master’s students is presently completing a PhD at Victoria University and NIWA on modelling sea ice in the Antarctic and Arctic.