Emily H. Stanley Luke C. Loken Nora J. Casson Peter A. Raymond Shaoda Liu Giuseppe Amatulli Ryan A. Sponseller Gerard Rocher-Ros 2023 <p><span>Methane (CH</span>₄<span>) is a potent greenhouse gas and its concentrations have tripled in the atmosphere since the industrial revolution. There is evidence that global warming has increased CH</span>₄<span>&nbsp;emissions from freshwater ecosystems</span>^{<a id="ref-link-section-d293024e611" title="Yvon-Durocher, G. et al. Methane fluxes show consistent temperature dependence across microbial to ecosystem scales. Nature 507, 488–491 (2014)." href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR1" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 1" data-mce-href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR1">1</a>,<a id="ref-link-section-d293024e614" title="Zhu, Y. et al. Disproportionate increase in freshwater methane emissions induced by experimental warming. Nat. Clim. Change 10, 685–690 (2020)." href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR2" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 2" data-mce-href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR2">2</a>}<span>, providing positive feedback to the global climate. Yet for rivers and streams, the controls and the magnitude of CH</span>₄<span>&nbsp;emissions remain highly uncertain</span>^{<a id="ref-link-section-d293024e620" title="Stanley, E. H. et al. The ecology of methane in streams and rivers: patterns, controls, and global significance. Ecol. Monogr. 86, 146–171 (2016)." href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR3" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 3" data-mce-href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR3">3</a>,<a id="ref-link-section-d293024e623" title="Rosentreter, J. A. et al. Half of global methane emissions come from highly variable aquatic ecosystem sources. Nat. Geosci. 14, 225–230 (2021)." href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR4" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 4" data-mce-href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR4">4</a>}<span>. Here we report a spatially explicit global estimate of CH</span>₄<span>&nbsp;emissions from running waters, accounting for 27.9 (16.7–39.7) Tg CH</span>₄<span> per&nbsp;year and roughly equal in magnitude to those of other freshwater systems</span>^{<a id="ref-link-section-d293024e632" title="Johnson, M. S. et al. Spatiotemporal methane emission from global reservoirs. J. Geophys. Res. Biogeosci. 126, e2021JG006305 (2021)." href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR5" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 5" data-mce-href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR5">5</a>,<a id="ref-link-section-d293024e635" title="Johnson, M. S., Matthews, E., Du, J., Genovese, V. &amp; Bastviken, D. Methane emission from global lakes: new spatiotemporal data and observation-driven modeling of methane dynamics indicates lower emissions. J. Geophys. Res. Biogeosci. 127, e2022JG006793 (2022)." href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR6" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 6" data-mce-href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR6">6</a>}<span>. Riverine CH</span>₄<span>&nbsp;emissions are not strongly temperature dependent, with low average activation energy (</span><i>E</i>_M<span> = 0.14 eV) compared with that of lakes and wetlands (</span><i>E</i>_M<span> = 0.96 eV)</span>^{<a id="ref-link-section-d293024e650" title="Yvon-Durocher, G. et al. Methane fluxes show consistent temperature dependence across microbial to ecosystem scales. Nature 507, 488–491 (2014)." href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR1" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 1" data-mce-href="https://www.nature.com/articles/s41586-023-06344-6#ref-CR1">1</a>}<span>. By contrast, global patterns of emissions are characterized by large fluxes in high- and low-latitude settings as well as in human-dominated environments. These patterns are explained by edaphic and climate features that are linked to anoxia in and near fluvial habitats, including a high supply of organic matter and water saturation in hydrologically connected soils. Our results highlight the importance of land–water connections in regulating CH</span>₄<span>&nbsp;supply to running waters, which is vulnerable not only to direct human modifications but also to several climate change responses on land.</span></p> application/pdf 10.1038/s41586-023-06344-6 en Nature Publications Global methane emissions from rivers and streams article