Estimation of the methane release intensity from the Arctic shelf bottom sediments

Abstract

Large reserves of carbon are preserved under conditions of subsea permafrost in the bottom sediments of the Arctic shelf. The existence of permafrost has created the necessary conditions for the thermodynamic stability of methane hydrates. Using a mathematical model that describes the thermal state of the sediment, we analyzed the dynamics of the permafrost and methane hydrates stability zone of the Arctic shelf bottom sediments for 100 thousand years in the future. Climate changes are considered under an idealized scenario of CO2 emissions into the atmosphere and changes in the parameters of the earth's orbit. The simulations for the next 100 kyr found that at the middle and shallow parts of the shelf the subsea permafrost survives, at least, for 9 kyr after the emission onset or even for several tens of kiloyears. Model estimates of methane emission from the Arctic shelf sediments to the water amounts up to 10 g/m2 per year.