Contribution of CO2 and CH4 emissions at ice-melt to annual emissions from 450 and 270 lakes, respectively, 1986 to 2014

The ice-covered period on lakes in the northern hemisphere can be
extensive, lasting up to 7 months of the year. During this time, C
cycling in lakes is altered affecting CO2 and CH4 dynamics below ice.
Lake ice impedes atmospheric exchange, trapping CO2 and CH4 in the
lake over winter. As lake ice-melts, CO2 and CH4 that has accumulated
over winter is emitted from the into the atmosphere. To investigate
the importance of CO2 and CH4 emissions during the ice-melt period, we
conducted a literature search for studies that had CO2 and CH4
emission estimates for both the ice-melt and open water period. From
these literature values, we could calculate the percent contribution
of the ice-melt period to annual CO2 and CH4 emissions. We obtained
data for 271 (n= 258) and 447 (n= 689) individual lakes, for CH4 and
CO2, respectively.