Assessing the ability of high latitude methane monitoring and modeling systems to detect climate driven changes

Climate change is affecting high latitude ecosystems in unprecedented ways as temperature increases more than two times higher than the global average. Large stocks of carbon sequestered in permafrost may be released as the region –that historically has been a carbon sink– appears to be turning into a source of carbon to the atmosphere. Therefore, it is of great importance to properly account for changes in the carbon cycle. Of note is that even if we are aware of the quantities of carbon release, there is a large difference in warming potential between carbon dioxide and methane, the latter is a far stronger short term greenhouse gas. 
Here we present work on two ESA projects which aim to address gaps in our knowledge of Arctic methane release: AMPAC-net and the CCI RECCAP-2 project. 

AMPAC-net is an ESA contribution to AMPAC, the 'Arctic Methane and Permafrost Challenge', which is a cooperation between ESA and NASA. Key topics include the combination of remote sensing with in-situ measurements for high latitude methane detection. The RECCAP2-CCI ‘REgional Carbon Cycle Assessment and Processes’, is in Phase 2 of ESA's 'Climate Change Initiative'. The overarching aim is to improve carbon budgets for the global stock take, with our sub-project focusing on permafrost region wetlands. As part of these research projects, we have reviewed past, current and required future state of methane monitoring and modeling in high latitudes. After an initial overview of past work, we follow with an analysis of the current state of Arctic methane research. Many projects aim to improve our understanding directly, but also indirectly for example by improved wetlands classification. We also highlight and discuss a major research challenge: the large discrepancy between top-down and bottom-up carbon budgets in high latitudes. We present our initial steps towards addressing this issue in a set of experiments where we use updated Arctic specific priors for methane inversions. Finally, we give an overview of high priority knowledge gaps that will need further addressing, and advise on how to move forward.