Enhanced Modern Heat Transfer to the Arctic by Warm Atlantic Water

Abstract

The Arctic is responding more rapidly to global warming than most other areas on our planet. Northward-flowing Atlantic Water is the major means of heat advection toward the Arctic and strongly affects the sea ice distribution. Records of its natural variability are critical for the understanding of feedback mechanisms and the future of the Arctic climate system, but continuous historical records reach back only ~150 years. Here, we present a multidecadal-scale record of ocean temperature variations during the past 2000 years, derived from marine sediments off Western Svalbard (79°N). We find that early-21st-century temperatures of Atlantic Water entering the Arctic Ocean are unprecedented over the past 2000 years and are presumably linked to the Arctic amplification of global warming.

Major impacts of climate change on deep-sea benthic ecosystems

“…Parts of the Antarctic Peninsula, including the WAP, are already experiencing the greatest increase in mean annual atmospheric temperature on Earth (Chapman and Walsh, 2007;Clarke et al, 2007;Solomon et al, 2007;Smale and Barnes, 2008), and temperatures at the seafloor in the Southern Ocean are predicted to rise by as much as 0.7°C at abyssal depths and 1.7°C at bathyal depths by 2100 ( Table 2). Field and modeling studies have also revealed rapid atmospheric and surface-water warming in the Arctic Ocean during recent decades (Overland et al, 2004;Spielhagen et al, 2011). Bathyal Arctic waters are following this rapid warming trend (Soltwedel et al, 2005), and temperatures at both bathyal and abyssal depths could increase by as much as 0.1-3.7°C relative to present-day temperatures by 2100 (Table 2; Figure 2).…”

Crenarchaea and phytoplankton coupling in sedimentary archives: Common trigger or metabolic dependence?

“…The core from the Fram Strait spans approximately the last 2000 yr. The age model for core MSM05/05-712-1 is based on five AMS 14 C age measurements (Spielhagen et al 2011). …”

Arctic Climate Tipping Points

“…Increased input of ocean heat from the Pacific (Shimada et al 2006;Woodgate et al 2006) and the Atlantic (Spielhagen et al 2011) are also contributing to ice melt. Finally, reductions in summertime cloud cover (the only season in which clouds have a net cooling effect in the Arctic) may have contributed to record sea-ice retreat in 2007 (Kay et al 2008).…”

“…The Atlantic waters that enter the Arctic Ocean at depth are now unusually warm and are enhancing heat flux to the surface and potentially contributing to sea-ice melt (Spielhagen et al 2011). The Barents Sea has warmed considerably at depth, tracking a strong phase of the Atlantic Multi-decadal Oscillation (Levitus et al 2009).…”

“…Unusually warm Atlantic waters are also intruding onto the shallow Laptev Sea (Dmitrenko et al 2010;Spielhagen et al 2011). This is part of the East Siberian Arctic Shelf, which is a large area (2.1 million km 2 ) of submerged permafrost and peatland that was flooded during the early Holocene (Shakhova et al 2010).…”