According to a study published journal Nature Climate Change, small natural ponds pose an overlooked danger for speeding up global warming.
Scientists in Britain found that such ponds — a metre across — gradually lose the capacity to soak up one kind of greenhouse gas and give off even more of another.
After seven years at higher-than-ambient temperatures, the ability of the ponds to absorb carbon dioxide was reduced by almost half, while methane release nearly doubled.
With soil, by contrast, warming initially stimulates CO2 output but then causes it to taper off.
The new findings matter because small ponds play an outsized role in the planet’s carbon cycle — the balance between input and output of greenhouse gases.
While covering only a tiny fraction of Earth’s surface area, they are responsible for about 40% of methane emissions from inland waters, earlier research has shown.
Methane is about 28 times more effective in trapping the sun’s radiation in our atmosphere than carbon dioxide, the dominant greenhouse gas.
Findings show that warming can fundamentally alter the carbon balance of small ponds over a number years. This could ultimately accelerate climate change.
Scientists warmed artificial ponds four degrees Celsius (7.2 degrees Fahrenheit), corresponding to the projected increase in global average temperatures by 2100 in temperate zones under a “moderate” climate change scenario.
The main source of man-made carbon pollution is the burning of fossil fuels, accounting for more than 70% of global greenhouse gas emissions. The rest comes from deforestation, the livestock industry, and agriculture.