New study shows warmup will boost methane releases
Small ponds could end up having a huge impact on Earth’s climate as they warm up due to heat-trapping greenhouse gas pollution, according to scientists from the University of Exeter and Queen Mary University of London. The researchers experimentally warmed a number small ponds by about 4-5 degrees Celsius over the course of seven years to study the effects of increased temperatures.
They found that warming water will accelerate climate change by reducing the amount of carbon dioxide stored in ponds and increasing releases of methane. Changes observed after the first year became “amplified” over a longer period, according to the study by the University of Exeter and Queen Mary University of London
After seven years, a pond’s ability to absorb carbon dioxide was reduced by almost half, while methane release almost doubled.
Lakes and ponds cover about 4 percent of Earth’s surface (excluding areas covered by glaciers and ice sheets) but they are disproportionately large sources of methane and CO2 to the atmosphere. According to the study, ponds smaller than one square meter are responsible for releasing about 40 percent of all methane emissions from inland waters.
“This is the first experiment to investigate the long-term effects of warming in aquatic ecosystems,” said lead author Professor Gabriel Yvon-Durocher, of the Environment and Sustainability Institute on the University of Exeter’s Penryn Campus in Cornwall.
“Given the substantial contribution small ponds make to the emission of greenhouse gases, it is vital to understand how they might respond to global warming. “Our findings show that warming can fundamentally alter the carbon balance of small ponds over a number of years, reducing their capacity to absorb carbon dioxide and increasing emissions of methane.
“The amplified effects of experimental warming we have observed in ponds are different to those we typically see on land, where large initial effects of warming appear to diminish over the long term,” Professor Yvon-Durocher said.
“This accelerating effect in ponds, which could have serious impacts on climate change, is not currently accounted for in Intergovernmental Panel on Climate Change models.”