# Rising Global Riverine Deoxygenation Rates and GHG Emissions Driven by the Synergistic Effects of Warming and Anthropogenic Land Use Expansion

## TL;DR

Rivers are losing oxygen and emitting more greenhouse gases due to climate warming and human land use changes, with impacts accelerating faster than in oceans or lakes.

## Contribution

This study quantifies the synergistic effects of warming and land use on river GHG emissions and deoxygenation using global satellite data and machine learning.

## Key findings

- Rivers show a global deoxygenation rate of 0.058 ± 0.01 mg L−1 per decade.
- Anthropogenic GHG emissions from rivers totaled 1.5 Pg‐CO2‐eq from 2002–2022.
- Rising water temperatures and land use expansion drive increased microbial activity and GHG supersaturation.

## Abstract

Global fluvial ecosystems are increasingly impacted by human activities, such as climate warming and land use changes; however, the combined effects of these pressures on river greenhouse gas (GHG) supersaturation and deoxygenation remain poorly understood. This study modeled past global trends (2002–2022) in river GHG saturation, dissolved oxygen (DO) levels, water temperature, and eight other water quality parameters using machine learning models powered by satellite observations. Our findings show significant global increases in river GHG supersaturation and deoxygenation, mainly driven by rising water temperatures (0.27°C ± 0.03°C per decade), increased precipitation, higher labile carbon and nitrogen inputs, and urban and cropland expansion. We estimate that anthropogenic GHG emissions from rivers due to these pressures totaled 1.5 Pg‐CO2‐eq over the 20‐year period. The increase in GHGs was accompanied by a global river deoxygenation rate of 0.058 ± 0.01 mg L−1 per decade, suggesting rivers may be losing oxygen up to 2.5 times faster than lakes and oceans globally.

Conceptual diagram summarizing study findings. Climatic shifts (river warming and intensified precipitation), together with expanding anthropogenic land uses, have driven elevated riverine GHG emissions and deoxygenation over recent decades. These responses reflect enhanced microbial activity under nutrient and organic matter enrichment at higher temperatures. Numbers indicate decadal estimates of warming, DO decline, and anthropogenic fractions of riverine GHG fluxes attributed to climatic and land‐use changes.