Like many Victorian natural philosophers, John Tyndall was fascinated by a great variety of questions. While he was preparing an important treatise on "Heat as a Mode of Motion" he took time to consider geology. Tyndall had hands-on knowledge of the subject, for he was an ardent Alpinist (in 1861 he made the first ascent of the Weisshorn). Familiar with glaciers, he had been convinced by the evidence — hotly debated among scientists of his day — that tens of thousands of years ago, colossal layers of ice had covered all of northern Europe. How could climate possibly change so radically?      

One possible answer was a change in the composition of the Earth's atmosphere. Beginning with work by Joseph Fourier in the 1820s, scientists had understood that gases in the atmosphere might trap the heat received from the Sun. As Fourier put it, energy in the form of visible light from the Sun easily penetrates the atmosphere to reach the surface and heat it up, but heat cannot so easily escape back into space. For the air absorbs invisible heat rays (“infrared radiation”) rising from the surface. The warmed air radiates some of the energy back down to the surface, helping it stay warm. This was the effect that would later be called, by an inaccurate analogy, the "greenhouse effect." The equations and data available to 19th-century scientists were far too poor to allow an accurate calculation. Yet the physics was straightforward enough to show that a bare, airless rock at the Earth's distance from the Sun should be far colder than the Earth actually is.      . . .

Tyndall set out to find whether there was in fact any gas in the atmosphere that could trap heat rays. In 1859, his careful laboratory work identified several gases that did just that. The most important was simple water vapor (H2O). Also effective were carbon dioxide (CO2), although in the atmosphere the gas is only a few parts in ten thousand, and the even rarer methane (CH4). Just as a sheet of paper will block more light than an entire pool of clear water, so a trace of CO2 or CH4 could strongly affect the transmission of heat radiation through the atmospheree.

High levels of the potent greenhouse gas have been detected down to a depth of 350 metres in the Laptev Sea near Russia, prompting concern among researchers that a new climate feedback loop may have been triggered that could accelerate the pace of global heating.

The slope sediments in the Arctic contain a huge quantity of frozen methane and other gases – known as hydrates. Methane has a warming effect 80 times stronger than carbon dioxide over 20 years. The United States Geological Survey has previously listed Arctic hydrate destabilisation as one of four most serious scenarios for abrupt climate change.

The international team onboard the Russian research ship R/V Akademik Keldysh said most of the bubbles were currently dissolving in the water but methane levels at the surface were four to eight times what would normally be expected and this was venting into the atmosphere.

The International Siberian Shelf Study (ISSS) Program is a Russian-Swedish led international collaboration that spans back about 15 years. The overarching aim of the ISSS Program is to investigate cryosphere-climate-carbon couplings on the extensive East Siberian Arctic Ocean Shelf.

The central focus of the ISSS-2020 expedition is one of the biggest open challenges in climate change science; understanding subsea and coastal permafrost thawing, hydrate collapse and the processes that result in releases of potent greenhouse gases such as methane, carbon dioxide and nitrous oxide. The expedition will be on board the largest Russian research vessel, the R/V Akademik Keldysh. The ISSS-2020 expedition builds on our expeditions and research over the past two decades to contribute fundamental knowledge of this vast, and vulnerable system so that we may move towards predicting how associated climate-carbon couplings and greenhouse gases releases may develop this century.

The expedition will run from 26 Sept – 4 Nov 2020 and will depart from and return to the White Sea port of Archangelsk, the cruise track stretching across the entire Arctic rim of the Eurasian margin.

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