UK scientists fear ocean's ability to absorb CO2 could be ebbing away

The UK's climate is facing an uncertain future after fresh research revealed the full destructive impact of greenhouse gases has been shielded by rising sea levels.

Scientists at Bangor University have discovered the ocean waters have absorbed half of all man's CO2 emissions but claim nature's effective filtering system could soon stop working.

In the report, researchers warn the UK should be prepared to "feel the full climatic brunt" despite carbon-reducing measures and legislation to slash the nation's output of greenhouse gases.

They found the 130m rise in sea levels since the last ice age has prevented the UK from suffering the full impact of man-made global warming as more harmful greenhouse gases have been absorbed by the oceans.

Currently only about half of man-made CO2 emissions stay in the atmosphere. The remaining 50 per cent is absorbed by the sea and land-based systems such as forests.

However, according to the study, the oceans could soon stop acting as a gas sponge, doubling the amount of greenhouse gas in the atmosphere and forcing an urgent recalculation of current climate change theories and predictions.

Researchers believe the UK could be hit hard by more extreme weather conditions with colder winters and scorching summers, torrential rainstorms and further flooding.

According to Dr Tom Rippeth, senior lecturer at Bangor University’s School of Ocean Sciences, it is crucial to understanding the natural processes controlling the absorption of CO2 to better understand and predict future climate change.

He said that looking at past climates helps us understand more about how our climate works – and the evidence looks ominous.

"We are currently getting a 50 per cent "discount" on the climatic impact of our fossil fuel emissions," he said. "Unfortunately, we have no guarantee that the 50 per cent discount will continue, and if it disappears we will feel the full climatic brunt of our unrelenting emission of carbon dioxide from burning fossil fuels.

He added that while there is already a lot of evidence that the seas are becoming more acidic and subsequently losing their ability to absorb gas, the latest research also demonstrated a direct link between the rise in sea levels and the ability of the oceans to absorb CO2.

"This advance is likely to have immediate influence on the research of other investigators," he said.

Fellow scientist, Professor James Scourse, Royal society senior research fellow at the school explained the thinking behind the study.

"We have been looking at how the strength of this CO2 sink has increased since the last ice age, as sea level has risen by about 130m," he said. "During this time the continental shelf seas have grown by 400 per cent, flooding an area of land equivalent to twice the area of the US."

He added that the team had been able to simulate the size of this CO2 sink over the past 22,000 years.

"In doing so we have shown that sea-level rise has resulted in a significant increase in the ocean uptake of CO2 from the atmosphere," he said, adding that "the results are consistent with the timing of changes in atmospheric CO2 concentration measured in Antarctic ice cores".

However, this impact is dwarfed when compared with the impact which man has had over the past 100 years by burning fossil fuels.

The results show that without the rise in sea level, and consequent flooding of the shelf seas, the amount of CO2 in the atmosphere would be rising at an even faster rate due to man's activities than it currently is.

In effect, past sea-level rise has so far helped put a brake on the impact of CO2 emissions on the atmosphere, but according to the research team we now have to ask how long this natural braking mechanism will continue to work.