For the second time in a week, climate scientists surprised with an increased CO2 absorption mechanism.

From the “But the science was settled!” department.

You may remember just four days ago, WUWT ran this story: Oops, Science Was “Settled”—Until It Wasn’t: Plants Absorb 31% More CO₂ Than We Thought

Now, hot on the heels of that one, another underestimated CO₂ absorption has been found: New Study Reveals Oceans Absorb More CO2 Than Previously Thought. The article states:

New research confirms that the cooler temperature of the ocean surface layer enhances CO₂ absorption, with the Atlantic absorbing 7% more CO₂ annually than previously estimated.

…

Scientists studied the “ocean skin” – a sliver less than 2 mm deep at the ocean surface that is fractionally cooler than the rest.

Theoretical and lab work have suggested this temperature difference should increase the amount of CO₂ absorbed by the ocean – but this had never been successfully observed at sea before.

The new study – led by researchers from the University of Exeter’s Penryn Campus in Cornwall – used precision measurements to confirm that the temperature of the ocean skin does indeed aid carbon absorption.

Carried out in the Atlantic, the findings suggest this ocean absorbs about 7% more CO₂ each year than previously thought. It might sound small, but when applied across all oceans this additional carbon absorption is equivalent to one and half times the carbon captured by annual forest growth in the Amazon rainforest.

Now, cumulatively, within a week, we now have a 38% difference in CO₂ absorption not previously known to climate science. That’s big.

The two recent studies on oceanic and terrestrial CO₂ absorption reveal significant, previously underestimated roles of natural carbon sinks, which have strong implications for climate models and predictions. Here’s an quick analysis of these findings and their combined impact on climate sensitivity and modeling.

1. Increased CO₂ Absorption by Oceans: The study led by the University of Exeter shows that the oceans absorb 7% more CO₂ annually than previously estimated. This is due to the “ocean skin” – a cooler, thin layer on the ocean’s surface that enhances carbon uptake. These findings suggest that the global ocean absorbs an amount of CO₂ equivalent to 1.5 times the carbon captured by Amazon forest growth, highlighting oceans’ role in moderating atmospheric CO₂ levels​.
   
2. Higher CO₂ Absorption by Terrestrial Plants: In parallel, research by Oak Ridge National Laboratory finds that plants absorb 31% more CO₂ than prior models indicated. By tracking carbonyl sulfide, scientists achieved a more accurate estimate of global photosynthesis, especially in tropical rainforests, which emerged as vital carbon sinks. The revised figure raises the annual global Gross Primary Production (GPP) from 120 to 157 petagrams of carbon, further underscoring the importance of natural carbon dioxide sequestration for climate balance​.

Cumulative Impact on Climate Models and Climate Sensitivity

The combined effect of these findings suggests that current climate models might be underestimating the natural carbon cycle’s role in moderating atmospheric CO₂ concentrations. With both oceans and land absorbing more CO₂ than previously thought, climate models need to incorporate these increased absorption rates to predict temperature and atmospheric CO₂ levels more accurately.

1. Climate Sensitivity Adjustments: The increased CO₂ absorption could reduce climate sensitivity estimates in the short term, as more CO₂ is removed from the atmosphere than expected.
2. Long-term Climate Projections: Enhanced natural absorption may temporarily ease the pace of CO₂ buildup, but as oceans approach saturation and deforestation pressures mount on terrestrial carbon sinks, this buffering effect may diminish over time. Including these findings could lead to more refined, temporally dynamic climate models that adjust carbon dioxide sink efficiency based on environmental changes.
3. Policy and Mitigation: Acknowledging the ocean and terrestrial ecosystems as increased carbon dioxide sinks emphasizes the importance of reevaluating climate science used to drive policy.

We’ve known for some time that climate models have been running “hot” due to some of the emission scenarios like RCP 8.5 being unrealistic in CO₂ growth rates in the future. See: New Confirmation that Climate Models Overstate Atmospheric Warming. Perhaps these new findings will cool some of those models (assuming climate science has any integrity left) and we’ll hear less about a projected climate doomsday being just around the corner.