Some of the ice shelves on the east side of the Antarctic Peninsula, which formerly covered roughly 10,000 square kilometres (3,900 sq mi) of the Weddell Sea, had completely disappeared by 2002.

Researchers from the Alfred Wegener Institute, on finding a Secchi disc visible at a depth of 80 metres (260 ft) on 13 October 1986, ascertained that the clarity corresponded to that of distilled water.

[3] In his 1950 book The White Continent, historian Thomas R. Henry writes: "The Weddell Sea is, according to the testimony of all who have sailed through its berg-filled waters, the most treacherous and dismal region on Earth.

"[4] He continues for an entire chapter, relating myths of the green-haired merman sighted in the sea's icy waters, the inability of crews to navigate a path to the coast until 1949, and treacherous "flash freezes" that left ships, such as Ernest Shackleton's Endurance, at the mercy of the ice floes.

The Weddell Sea is an important area of deep water mass formation through cabbeling, the main driving force of the thermohaline circulation.

Otto Nordenskiöld, leader of the 1901–1904 Swedish Antarctic Expedition, spent a winter at Snow Hill with a team of four men when the relief ship became beset in ice and was crushed.

[9] The Weddell Sea is one of few locations in the World Ocean where deep and bottom water masses are formed to contribute to the global thermohaline circulation which has been warming slowly over the last decade.[when?

Thus, in addition to a wind-driven gyre component of the boundary current, a deeper circulation whose dynamics and transports reflect an input of dense water in the southern and southwestern Weddell Sea are expected.

[12] The predominance of strong surface winds parallel to the narrow and tall mountain range of the Antarctic Peninsula is a remarkable feature of weather and climate in the area of the western Weddell Sea.

These winds are of interest not only because of their effect on the temperature regime east of the peninsula but also because they force the drift of ice northeastward into the South Atlantic Ocean as the last branch of the clockwise circulation in the lower layers of the atmosphere along the coasts of the Weddell Sea.

[13] Strong surface winds directed equatorward along the east side of the Antarctic Peninsula can appear in two different types of synoptic-meteorological situations: an intense cyclone over the central Weddell Sea, a broad east to west flow of stable cold air in the lowest 500-to-1000-metre layer of the atmosphere over the central and/or southern Weddell Sea toward the peninsula.

This process leads to the formation of a high-pressure ridge over the peninsula (mainly east of the peak) and, therefore, a deflection of the originally westward current of air to the right, along the mountain wall.

[14] In February 2021 the Alfred Wegener Institute for Polar and Marine Research with RV Polarstern, a colony of approximately 60 million Jonah's icefish was found to inhabit an area in the Weddell Sea.