Life Sciences Department, The Natural History Museum, London, UK.
Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA.
Glob Chang Biol. 2024 Jun;30(6):e17390. doi: 10.1111/gcb.17390.
Methane is a powerful greenhouse gas, more potent than carbon dioxide, and emitted from a variety of natural sources including wetlands, permafrost, mammalian guts and termites. As increases in global temperatures continue to break records, quantifying the magnitudes of key methane sources has never been more pertinent. Over the last 40 years, the contribution of termites to the global methane budget has been subject to much debate. The most recent estimates of termite emissions range between 9 and 15 Tg CH year, approximately 4% of emissions from natural sources (excluding wetlands). However, we argue that the current approach for estimating termite contributions to the global methane budget is flawed. Key parameters, namely termite methane emissions from soil, deadwood, living tree stems, epigeal mounds and arboreal nests, are largely ignored in global estimates. This omission occurs because data are lacking and research objectives, crucially, neglect variation in termite ecology. Furthermore, inconsistencies in data collection methods prohibit the pooling of data required to compute global estimates. Here, we summarise the advances made over the last 40 years and illustrate how different aspects of termite ecology can influence the termite contribution to global methane emissions. Additionally, we highlight technological advances that may help researchers investigate termite methane emissions on a larger scale. Finally, we consider dynamic feedback mechanisms of climate warming and land-use change on termite methane emissions. We conclude that ultimately the global contribution of termites to atmospheric methane remains unknown and thus present an alternative framework for estimating their emissions. To significantly improve estimates, we outline outstanding questions to guide future research efforts.
甲烷是一种强大的温室气体，比二氧化碳的温室效应更强，它会从湿地、永久冻土层、哺乳动物肠道和白蚁等多种自然源中释放出来。随着全球气温的持续升高，记录不断被打破，量化关键甲烷源的排放量变得前所未有的重要。在过去的 40 年里，白蚁对全球甲烷预算的贡献一直存在争议。最新的白蚁排放量估计值在 9 到 15TgCH 年之间，约占自然源（不包括湿地）排放量的 4%。然而，我们认为，目前估算白蚁对全球甲烷预算贡献的方法存在缺陷。关键参数，即土壤、枯木、活树干、地上土丘和树栖巢中的白蚁甲烷排放，在全球估计中基本上被忽略了。这种遗漏是因为缺乏数据，而且研究目标严重忽视了白蚁生态学的变化。此外，数据收集方法的不一致性使得计算全球估计所需的数据无法汇总。在这里，我们总结了过去 40 年的进展，并说明了白蚁生态学的不同方面如何影响白蚁对全球甲烷排放的贡献。此外，我们还强调了可能有助于研究人员在更大范围内研究白蚁甲烷排放的技术进步。最后，我们考虑了气候变暖与土地利用变化对白蚁甲烷排放的动态反馈机制。我们得出的结论是，白蚁对大气甲烷的全球贡献仍不清楚，因此提出了一种估算其排放量的替代框架。为了显著提高估算值，我们列出了需要解决的问题，以指导未来的研究工作。
