Abstract
Permafrost wetlands are closely related to potential greenhouse gas emissions under climate warming. In recent decades, climate change and human activities have induced extensive permafrost degradation, severely influencing the stability of wetlands in permafrost regions. The widely observed significant changes in vegetation cover, hydrological conditions, and soil carbon stability are strongly affecting the carbon cycle and the carbon sources/sinks of permafrost wetlands. In this review, research progress on the response and feedback mechanisms of wetland ecological processes to permafrost degradation under the influences of climate change is first explored, including the impacts of permafrost degradation on the vegetation dynamics, hydrological processes, soil carbon decomposition, greenhouse gas emissions, and carbon feedback. In addition, several questions regarding recent advances are raised and some suggestions are provided for future related research pertaining to the following issues: (i) linkages and response relationships between permafrost degradation and the vegetation-hydrology-carbon cycle in permafrost wetlands, (ii) stabilization mechanisms of their carbon sink function, (iii) accurate estimation of the carbon sequestration rate and sink potential, and (iv) carbon feedback in permafrost wetlands under future climate change scenarios. The findings will provide critical scientific evidence and data support for protecting wetland ecosystems in permafrost regions under changing climate conditions and the implementation of carbon peaking and carbon neutrality strategies.