Northern permafrost soils represent the largest terrestrial organic carbon pool on Earth. A study the northern circumpolar permafrost zones reveals that landscapes susceptible to abrupt thawing with the release of significant quantities of carbon dioxide and methane cover 20% of the northern permafrost region and store up to half its soil organic carbon.
As the Earth warms, permafrost soils melt and this old carbon is released into the atmosphere as methane and CO2. Using radiocarbon dating of methane bubbles and soil organic carbon from lakes formed by melting thermafrost in Alaska, Canada, Sweden and Siberia combined with remote sensing it is found that methane and carbon dioxide releaed in the Arctic region during the past 60 years is much less than the CO2 contributed annually from anthropogenic and other sources.
Improved data coverage and analysis has made it possible to reconstruct temperature profiles across most ocean basins and at all depths to 6000 meters (m) from 1960 to 2015. The reconstructions reveal accelerating heating in the upper layers above 2000 m. Ocean warming is stronger since the late 1980s compared to the 1960s to the 1980s.
The last deglaciation was characterized by increases in surface temperatures of 10-15 °C punctuated by millennial-scale warming/cooling periods, pulses of increasing atmospheric carbon dioxide and asynchronously increasing methane. A geospatial-temporal variance analysis reveals a global warming trend correlating with rising CO2 on which is superimposed second trend millennial-scale regional warming/cooling periods associated with variation in the strength of the Atlantic overturning current.