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This empirical sea ice growth relation gives thickness $H$ in metres from accumulated freezing degree-days $N$. Its coefficient includes the specified units and calibration. It is not a complete energy-balance model: snow, ocean heat and changing forcing can alter its applicability. Inversion gives $N=(H/0.0133{)}^{1/0.58}$.

Invert the Lebedev ice-growth law to obtain the original accumulated freezing degree-days:The average cold over $275$ days is therefore approximately $12.56\mathrm{K}$ below the reference. Assuming the warmed days remain below the freezing-degree-day threshold, a $4\mathrm{K}$ increase removes $4\times 275=1100$ degree-days. HenceThe estimated end-of-winter thickness falls by about $0.30$ m, or $20\%$. This applies the same empirical growth law to the altered temperature forcing; it does not add changes in snow, winds or ocean heat.

Warmer air increases surface melt during the warm season, lengthens the melt season, and reduces the accumulated freezing degree-days available for winter growth. Enhanced downward heat transfer can therefore thin the cover even without extra ocean heat. It provides a broad thermodynamic influence on Arctic sea ice decline, while regional winds and cloud conditions determine part of the local response.