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This study examined the long-term trends in Arctic ambient methane (CH₄) mixing ratios over 1986&#8211;2014 and investigated their potential causes. Significant correlations between carbon monoxide (CO) and CH₄ in Barrow, Alaska (r = &#8722;0.59, <i>p</i> = 0.007) and Alert, Canada (r = &#8722;0.62, <i>p</i> = 0.004) with the strongest correlations occurring in April (r = &#8722;0.81, <i>p</i> = 0.000, and r = &#8722;0.80, <i>p</i> = 0.000) suggest local to global anthropogenic contributions to ambient CH₄ during the cold months. Backward trajectories indicate a significant influence (27% of total trajectories) of local emissions from the Prudhoe Bay Oil Field on ambient CH₄ in Barrow in winter, and this influence was dominated by other factors in summer. The mean CH₄ wetland emission flux in Barrow over 1986&#8211;2014 was estimated to be 0.008 &#177; 0.002 &#181;g m^&#8722;2 s^&#8722;1 while in Tiksi, Russia it was 0.010 &#181;g m^&#8722;2 s^&#8722;1 over 2012&#8211;2016, which is comparable to the lower end of measurements in the literature. Note that in Barrow, there was a decrease in wetland flux from 0.0083 &#177; 0.002 &#181;g m^&#8722;2 s^&#8722;1 over 1986&#8211;1998 to 0.0077 &#177; 0.002 &#181;g m^&#8722;2 s^&#8722;1 from 1999&#8211;2006 followed by an increase to 0.0081 &#177; 0.002 &#181;g m^&#8722;2 s^&#8722;1 over 2007&#8211;2014. Although the difference between the three values is not statistically significant due to small sample size, it is indicative of possible warm season wetland emissions contributing to the zero-growth period. Strong support for this hypothesis is that these changes are consistent with a concurrent drop in summertime temperature possibly causing a decrease in wetland emissions over 1998&#8211;2006 based on the statistically significant correlations between temperature and CH₄ during August through November (r ~ 0.36&#8211;0.56, <i>p</i> = &#8804;0.05). In a warming climate, permafrost thawing can increase CH₄ wetland emissions and also decrease wetlands making it a complex problem, and, hence, further study is needed to better understand the mechanisms driving long-term trends in Arctic CH₄.