Carbon Emissions
Fossil fuel flux (rate) and change in reservoir size are more than a decade old.
Map from NASA, May 2011 - in metric tonnes of carbon per hectare. About 250 hectares per square mile. Mg = tonnes.
are apparently for above-ground carbon only
Permafrost covers 1/6 to 1/4 of northern hemisphere land surface, 15-25 million square kilometers. Its top 10 feet hold ~ 1.9 trillion tons of carbon. That's 1,200 tonnes (Mg) / hectare (120 kg/sq m, 12 g/sq cm): 6-7 times what NASA shows for tropical rainforests. Mongabay et al. estimate 168-420 (µ 302) Mg / hectare for various tropical rainforests, a bit more than NASA.
Below is world soil organic carbon density (tons/hectare, as above).
USDA: Natural Resource Conservation Service, 2000.
Soil carbon densities for most of Russia, Siberia, Europe, Alaska, and Canada exceed total tropical ones for soil + trees.
Albedo measures reflection.
% change from average (mean, µ) , from American Meteorological Association (full study available on Overviews page).
The trend is that Earth is getting darker. This is consistent with ice loss.
Scientists Have Long Feared Soil Climate ‘Feedback’. Now It’s Happening. 1116 - more than just permafrost soils
Global CO2 Emissions Still Accelerating, even as Human Ones Level Off 0516 -
The increase in CO2 levels in the air is accelerating, even as human CO2 emissions from fossil fuels are leveling off.
This suggests some combination of fading carbon sinks in the ocean and the land biosphere, with rising emissions from natural sources - permafrost, forest fires, methane hydrates, and peat fires - as well as agriculture and land use changes.
Carbon Dioxide Removal and Reliable Sequestration - NAS 0215 - PDF, 155 pp
Soil lost 230 GT of carbon over the past 10,000 years, due to land conversion and land use. This comparesw to 365 GT added from burning fossil fuels. Feasible soil carbon sequestration, by moving carbon from the air back into soil, is estimated (to 2065) at 30-50 GT of carbon.
Other major methods to sequester significant amounts of carbon include accelerated rock weathering (almost as much potential), ocean iron fertilization (very costly, with 90-300 GT potential), bio-energy with carbon capture (100-1,000 GT), direct air capture, and sequestration for the 2 capture-only methods. Cost estimates range from $1 to $1,000 per tonne of CO2 removed, depending on the method, with wide estimates for each method.
Section Map: Carbon Emissions