Earth Will Experience Highest Carbon Dioxide Levels For 3.3 Million Years
Within the next five years, Earth’s carbon dioxide (CO2) levels are set to rise to their highest in 3.3 million years, according to new research.
The study, by researchers at the University of Southampton, has estimated that there will be more CO2 in our planet’s atmosphere in 2025 than during the warmest part of the Pliocene epoch around 3.3 million years ago.
In a paper published last week in Nature Scientific Reports, the team detailed their work, which involved studying the chemical composition of tiny fossils, around the size of a pin head, which had been taken from deep ocean sediments of the Caribbean Sea.
Then, they used the data they had collected to reconstruct the concentration of the CO2 in the Earth’s atmosphere during the Pliocene epoch – when temperatures were around 3°C warmer than today, the polar ice caps were smaller and we had higher global sea levels.
Dr Elwyn de la Vega, who led the study, wrote in the report:
Knowledge of CO2 during the geological past is of great interest because it tells us how the climate system, ice sheets and sea-level previously responded to the elevated CO2 levels.
We studied this particular interval in unprecedented detail because it provides great contextual information for our current climate state.
The team’s work focused on a period of 200,000 years, between 3.35 and 3.15 million years ago, which allowed them to create a clearer picture on how CO2 levels have changed every 3,000 to 6,000 years.
They discovered that during the warmest period, the CO2 levels were between 380 and 420 parts per million (ppm). To put that into perspective, levels crossed the 417ppm threshold for the first time since records began, in May of this year.
Dr Thomas Chalk, a co-author of the study, added:
Focusing on a past warm interval when the incoming insolation from the sun was the same as today gives us a way to study how Earth responds to CO2 forcing. A striking result we’ve found is that the warmest part of the Pliocene had between 380 and 420 parts per million CO2 in the atmosphere. This is similar to today’s value of around 415 parts per million, showing that we are already at levels that in the past were associated with temperature and sea-level significantly higher than today.
In the last 10 years, CO2 levels have increased by around 2.4ppm each year, which if it were to continue, would mean in five years’ time, levels will have well exceeded those seen during the Pliocene epoch.
Dr Elwyn de la Vega concluded:
Having surpassed Pliocene levels of CO2 by 2025, future levels of CO2 are not likely to have been experienced on Earth at any time for the last 15 million years, since the Middle Miocene Climatic Optimum, a time of even greater warmth than the Pliocene.
You can read the full paper here.
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CreditsNature Scientific Reports
Nature Scientific Reports