A research squad from the University of Southampton has estimated the amount of atomic number 6 dioxide present during the warm part of the Pliocene epoch about 3.3 million years ago . At the time , the sea were much higher and the polar caps were much humble , with the planet being 3 ° C ( 5.4 ° F ) lovesome than it is today . The researchers believe that by 2025 , there will be a higher amount of CO2 in the atmosphere than any meter during the last 3.3 million year . The findings are release inScientific Reports .
The squad used microscopic fossilize zooplankton from deep ocean deposit from the Caribbean Seato determine atmospheric CO2 . The writing of their shell reckon on the pH of brine , which in turn is influence by atmospherical CO2 . The work focused on a period of 200,000 years between 3.35 and 3.15 million years ago , with a direction on 3.3 million year ago at the beginning of the mid - Piacenzian Warm Period , when the mood became slowly warmer until the tight global temperature was much higher than today . In doing so , the researchers were able to bring about a image of how atomic number 6 dioxide level have changed every 3,000 to 6,000 old age .
" Knowledge of CO2 during the geologic yesteryear is of swell stake because it evidence us how the clime arrangement , frappe sheet and sea - floor previously responded to the noble-minded CO2 levels . We studied this particular separation in unprecedented detail because it provides bully contextual entropy for our current climate country , " Dr Elwyn de la Vega , who led the study , order in astatement .
Dr de la Vega and fellow worker established that during the warmest part of the period , carbon dioxide level were between 380 and 420 parting per million ( ppm ) CO2 in the atmosphere . In May 2020 , it crossed the417 ppm thresholdfor the first time since records begin .
The value changes always due to several factors , but the increasing trend is well demonstrate . Over the last X , the tier has increased by about 2.4 ppm per yr . Even assuming a conservative value for the current level , it is clear that in five years ’ time it will exceed a grade unseen since the Pliocene .
" Having surpassed Pliocene levels of CO2 by 2025 , next levels of CO2 are not likely to have been experienced on Earth at any clip for the last 15 million years , since the Middle Miocene Climatic Optimum , a prison term of even greater lovingness than the Pliocene , " Concluded Dr de la Vega .
It is not just the amount of carbon dioxide in the standard atmosphere that concerns expert , it is also how chop-chop it has been release and the combine effects with other greenhouse gas such as methane .
