THE ARCTIC OCEAN WARMS FROM BELOW THIS POST IS A PRESENTATION OF THE FINDINGS IN “The Arctic Ocean warms from below Eddy C. Carmack William J. Williams Sarah L. Zimmermann Fiona A. McLaughlin, Geophysical Research Letters, 2012. LINK TO FULL TEXT: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012GL050890 ABSTRACT: The old (∼450‐year isolation age) and near‐homogenous deep waters of the Canada Basin (CBDW), that are found below ∼2700 m, warmed at a rate of ∼0.0004°C yr−1 between 1993 and 2010. This rate is slightly less than expected from the reported geothermal heat flux (Fg ∼ 50 mW m−2). A deep temperature minimum Tmin layer overlies CBDW within the basin and is also warming at approximately the same rate, suggesting that some geothermal heat escapes vertically through a multi‐stepped, ∼300‐m‐thick deep transitional layer. Double diffusive convection and thermobaric instabilities are identified as possible mechanisms governing this vertical heat transfer. The CBDW found above the lower continental slope of the deep basin maintains higher temperatures than those in the basin interior, consistent with geothermal heat being distributed through a shallower water column, and suggests that heat from the basin interior does not diffuse laterally and escape at the edges. The deep waters of the Arctic Ocean form in the Nordic seas and enter the Arctic Ocean through Fram Strait. The Arctic Ocean itself contains two main basins; the Eurasian and Canadian, separated by the Lomonosov Ridge with a sill depth of ∼2000 m. The Canadian Basin has the largest volume and contains the oldest deep water, with 14C isolation age estimates of ∼450 years. In turn, the Canadian Basin is separated by the Alpha‐Mendeleyev ridge complex into the Makarov and Canada Basins. The deep waters of the Canada Basin (CBDW) are near‐homogeneous, varying in potential temperature by less than 0.001°C between ∼2700 m and the bottom, a feature ascribed to geothermal heating and vertical convection. The geothermal heat flux in the Canadian Basin is 40–60 mW/m2. Salinity in the Canadian Basin increases with depth to ∼2700 m, but is nearly constant below this depth. A near‐homogenous bottom waters temperature is observed in the Eurasian Basin but with a temperature change in the bottom layer attributed to geothermal heating. In the Canada Basin bottom waters that temperature is near‐constant with time. Some heat escapes vertically through the overlying deep transitional layer and that heat was lost mainly around the perimeter of the basin. Here, using data from annual surveys of the southern Canada Basin between 2002 and 2010, we re‐examine role of geothermal heating in CBDW, describe temporal and spatial patterns in water mass properties, and propose heat exchange mechanisms that involve diffusive and thermobaric instabilities. FINDINGS: CBDW appears as a thick, near‐homogenous bottom layer extending from ∼2700 m to the bottom. Above lies an ∼300‐m‐thick deep transitional layer that is characterized by a temperature–salinity step structure, and the top of this layer is marked by a temperature minimum (Tmin) at ∼2400 m, the sill depth at Cooperation Gap on the Alpha‐Mendeleyev Ridge complex. The staircase structure, through which both the mean temperature and mean salinity increase with depth, is observed at all stations across the entire basin and has been a persistent feature for at least two decades. The step structure is typically characterized by three to four mixed layers that are 10–60 m thick and are separated by 2–20 m‐thick interfaces over which changes are δθ ∼ 0.003°C and δS ∼ 0.0007. The θ/S properties of the deep basin show that stratification below the Tmin is marginally stable with respect to density calculated at 3000 m and that those of the Tmin itself closely match those of the Makarov Basin at sill depth, pointing to this as the likely source maintaining the Tmin layer. For any given year the θ of CBDW within the deep basin is laterally near‐uniform, varying by less than 0.0007°C across the full study area, reflecting the isolation of the basin and also the ubiquity of geothermal heating. The θ of the Tmin, however, shows greater spatial variability. Evolution of the Deep Water in the Canadian Basin in the Arctic Ocean in: Journal of Physical Oceanography Volume 36 Issue 5 (2006) (a) Schematic of Canada Basin Bottom Water (CBDW) structure and processes; MB is the Makarov Basin, A/M is the Alpha Mendeleyev Ridge, CB is the Canada Basin, Slope is the continental slope in the south and east. E and D are entrainment and detrainment associated with a hypothetical descending plume of cold salty water from the shelf. (b–d) Changes in potential temperature (red), salinity (blue) and density in the central Canada Basin at JOIS station CB‐15 at 77N, 140W (see Figure 1b, green dot) in 2003 (thin lines) and 2010 (thick lines). The profile from 2000 m to the bottom is shown in Figure 2b, the deep transitional layer (DTL) from 2450 to 2750 m is shown in Figure 2c and potential temperature vs. salinity is shown in Figure 2d with contours of potential density referenced to 3000 db. Time sequence of potential temperature profiles in the deep Canada Basin from 2002 to 2010 reveals the steady increase in temperature of the CBDW. This rate of warming is consistent with geothermal heat flux. A least‐squares fit to all available CBDW temperature data from 1993–2010 for stations deeper than 3000 m gives a rate of warming of ∼0.0004°C/yr; a similar rate of warming is observed in the Tmin, but with a much larger spatial variation. CONCLUSIONS: THE ARCTIC OCEAN IS GEOLOGICALLY ACTIVE WITH SIGNIFICANT SOURCES OF GEOTHERMAL HEAT FLOW FROM THE MIDDLE OF THE PLANET. THE ARCTIC OCEAN WARMS FROM BELOW. THEREFORE ARCTIC OCEAN TEMPERATURE DYNAMICS AND ICE MELT EVENTS CANNOT BE UNDERSTOOD IN ATMOSPHERIC TERMS. YET, WHAT WE SEE IN CLIMATE SCIENCE IS AN EXCLUSIVE RELIANCE ON ATMOSPHERIC PHENOMENA TO EXPLAIN ALL OCEAN WARMING AND ICE MELT PHENOMENA IN THE ARCTIC. THIS ANALYSIS BY CLIMATE CHANGE SCIENTISTS IS NOT CREDIBLE AND INDICATIVE OF THE CORRUPTION OF SCIENCE BY ACTIVISM.