Researchers from Umeå University have uncovered a startling revelation – inland waters, such as streams, rivers, and lakes, are releasing substantial amounts of greenhouse gases, but this critical factor is often overlooked in climate assessments. This oversight has led to inaccurate evaluations of the carbon cycle’s response to climate change, particularly in cold regions experiencing rapid warming. The implications of this discovery are profound, as it suggests that the role of inland waters in greenhouse gas emissions may become increasingly significant as global temperatures continue to rise.
Pulling Back the Curtain on the Ghost of Carbon
Indeed, most climate assessments have treated greenhouse gases exchanged on land but failed to consider the transport of significant amounts of carbon from land into one of the largest reservoirs in cold regions — their abundant inland waters. While this can be understood as a counterintuitive oversight, it has left an important void in our knowledge of the carbon cycle and its response to climate change.
In a new Perspective, Karlsson argues that, “Current data and approaches are likely insufficient to represent contemporary and future carbon flows between land and water systems. The finding has set off a fresh round of research, as scientists try to understand how important inland waters really are to the global carbon cycle.
It turns out huge inland water a climate threat
Over the entire land surface of the northern hemisphere, a much larger area emits GHGs, led by scientists from Sichuan University in China and Umeå Universitet opens a new window regarding understanding global carbon dynamics.
The research — which was published in Science Advances — reveals that lakes and rivers in cold regions play a larger role in the inland water methane output than researchers had previously believed. This emission can cancel out a sizeable portion of the carbon uptake by terrestrial ecosystems in the north, which would make matters even worse
The study also revealed another double whammy, that rivers release global warming gases at a much higher rate than lakes do, and the greatest difference lay by far in icy regions where much of the landscape is overlain with permafrost. The UC Riverside-led research cautions that the warming of permafrost results in substantial amounts of carbon escaping to the atmosphere–carbon that had been unavailable for millennia, locked belowground.
Closing the Doughnut Hole: A Water-Smart Future Requires a New Role for Urbanizing Tributaries
The new study has profound implications; as global temperatures warm, cold regions could play a larger role in net emissions of greenhouse gases.
A further paper, published in Nature Water last year, has Karlsson saying — that climate reports would benefit from taking into account land-water carbon cycle processes that affect the coupled carbon stocks and fluxes. He points out some of the most important problems but also highlights the cross-disciplinary and partly valid nature of scientific investigation of land and water systems at relevant scales.
To move the field forward, we will need collaborative studies across disciplines and different approaches. Karlsson explains, “Ideally the research infrastructures and funding and training programs should be designed to enable this type of integrated collaborative [team-based] approaches.
Examining the world’s forgotten carbon pool The study highlights the global importance of this neglected and abundant C-stock, but also provides useful information for comprehensive climate assessments that can inform strategies for mitigating/adapting to climate change.
