Is ice CO2

Less CO2 from melting icebergs

As a result of global warming, icebergs are melting around the world. On the one hand, this leads to a rising sea level - but at the same time it also leads to a slower rise in the CO2 concentration in the atmosphere.

Scientists from the University of Sheffield have found out more about this by analyzing satellite images of around 200 giant icebergs in the Southern Ocean around Antarctica over a period of ten years.

The report has now been published in the journal "Nature Geoscience". In it, the researchers describe the effect of increased plankton formation in meltwater and the associated binding of CO2.

Well-known phenomenon

The nutrient-rich meltwater from the icebergs stimulates phytoplankton growth. If plankton grows there, carbon dioxide is drawn out of the atmosphere. And when the plants die, they take it with them into the depths of the ocean. It is tied there for several centuries or millennia.

The formation of plankton and the binding of CO2 through melting ice have been known to science for years, but the extent of the effects now described is not yet. "That seems much bigger than previously thought," study author Grant Bigg told DW.

CO2 makes the oceans acidic and the ecosystem suffers. A reduction in CO2 would also be helpful here.

Overall effect of the ice melt still unexplained

Since the beginning of the industrial revolution around 1850, the CO2 concentration in the atmosphere has risen from 280 ppm (parts per million) back then to 400 ppm today. It is currently increasing very rapidly, by around two ppm per year.

According to Bigg, the melting icebergs have a dampening effect on the increasing CO2 concentration, "they slow down the increase in CO2 concentration by five to ten percent per year" and could thus possibly slow down global warming somewhat.

In addition, there are many other questions that remain open. "We still do not fully understand the climate system. I would not be surprised if there are possible accelerating and decelerating effects in global warming," said Bigg.

Long-term forecast

In their study, the authors did not assess whether the melting icebergs are overall good or bad for stabilizing the earth's temperature.

So far, a large part of the sunlight has been reflected back into space through the ice. If it continues to melt, the earth will also swallow this light energy and thus further accelerate global warming, warn experts.