Re: So, how much gas per day ?
Normalise your units first!
There are a million grams in a tonne!
14,056,000 km² = 14,056,000,000,000 (1.4056 E13) m²
2mg/m² per day = 0.002 g = 0.000002 kg/m² (2 E-6)
= 1.4056 E13 × 2 E-6
= 28,112,000 kg
= 28,112 tonnes per day, or a volume of about 15 cubic kilometers per year.
In energy terms at 5.55 E7 J per kg:
= 365.25 × 5.55 E7 × 2.8112 E7 = 5.7 E17 J per year
American energy consumption about
28,714 TWh or 1.03 E20 J
It represents about 0.55% of America's energy consumption.
To get an easier to grasp handle on how this compares with American yearly CO2 emissions, with methane at 20x equivalence:
28,112 x 365.25 x 20 = 205,358,160 million tonnes.
With US CO2 emissions approx 5 Gt per year, arctic methane emissions are adding an extra 4% of US CO2 emissions to GW. Not an insignificant amount.
So 2mg methane per square metre sounds tinier than a mosquito fart, but it adds up.
As positive feedbacks kick in over the next few years, this will rise and reduce radiative ability further, causing increased melting of the ice.