The global rate of photosynthesis, the chemical process governing the way ocean and land plants absorb and release CO2, occurs 25 percent faster than previously thought, a team of US, Netherlands and Australian scientists said on Thursday.

Atmospheric chemist Dr. Colin Allison, of Commonwealth Scientific and Industrial Research Organisation (CSIRO) Marine and Atmospheric Research, and his colleagues reported their findings on Thursday in the journal Nature.

From analysing more than 30 years of data collected by Scripps Institution of Oceanography, University of California, San Diego of US, the scientists concluded that current estimates of carbon assimilation by plants through photosynthesis across the globe are not high enough and will need to be revised.

"Our analysis suggests that current estimates of global primary production are too low and the refinements we propose represent a new benchmark for models to simulate carbon cycling through plants, " Dr. Allison said in a statement released on Thursday.

The team made the finding by tracing the path of oxygen atoms in CO2 molecules, and Dr. Allison said the current global gross primary production estimates of 120 billion tonnes of carbon a year should be revised to between 150 and 175 billion tonnes of carbon a year.

The research reveals that the regular variations are linked to El Nino-Southern Oscillation phenomenon. In the tropics, where the effects of El Nino are the strongest, oxygen isotopes in CO2 correlate with those in precipitation.

Dr. Allison said the finding is especially significant to climate science, and to policymakers, because of its relevance to global management of carbon emissions.

"These results can be used to validate the biospheric components included in carbon cycle models and, although still tentative, may be useful in predicting future climate change," Dr. Allison said.