Study shows today’s atmospheric carbon dioxide levels greater than 23 million-year record


Share post:

A common message in use to convey the seriousness of climate change to the public is: “Carbon dioxide levels are higher today than they have been for the past one million years!” This new study by Brian Schubert (University of Louisiana at Lafayette) and coauthors Ying Cui and A. Hope Jahren used a novel method to conclude that today’s carbon dioxide (CO2) levels are actually higher than they have been for the past 23 million years.

Study shows today's atmospheric carbon dioxide levels greater than 23 million-year record
The remains of land plants can be used to calculate the amount of CO2 in Earth’s atmosphere
[Credit: A. Hope Jahren]

The team used the fossilized remains of ancient plant tissues to produce a new record of atmospheric CO2 that spans 23 million years of uninterrupted Earth history. They have shown elsewhere that as plants grow, the relative amount of the two stable isotopes of carbon, carbon-12 and carbon-13 changes in response to the amount of CO2 in the atmosphere. This research, published this week in Geology, is a next-level study measuring the relative amount of these carbon isotopes in fossil plant materials and calculating the CO2 concentration of the atmosphere under which the ancient plants grew.

Furthermore, Schubert and colleagues’ new CO2 “timeline” revealed no evidence for any fluctuations in CO2 that might be comparable to the dramatic CO2 increase of the present day, which suggests today’s abrupt greenhouse disruption is unique across recent geologic history.

Another point, important to geological readers, is that because major evolutionary changes over the past 23 million years were not accompanied by large changes in CO2, perhaps ecosystems and temperature might be more sensitive to smaller changes in CO2 than previously thought. As an example: The substantial global warmth of the middle Pliocene (5 to 3 million years ago) and middle Miocene (17 to 15 million years ago), which are sometimes studied as a comparison for current global warming, were associated with only modest increases in CO2.

Source: Geological Society of America [June 01, 2020]



Related articles

‘Insectageddon’ is ‘alarmist by bad design’: Scientists point out the study’s major flaws

Amidst worldwide publicity and talks about 'Insectageddon': the extinction of 40% of the world's insects, as estimated in...

New insights into the geographical landscape of prehistoric central Tibet

A team of scientists from the UK and China have uncovered new evidence, using recently-discovered 25-million-year-old fossilised palm...

UN Security Council declares war on ivory poachers, traffickers

The United Nations Security Council is cracking down on ivory hunters and traffickers who finance armed groups in...

Ancient ice reveals mysterious solar storm 9,200 years ago

Through analysis of ice cores from Greenland and Antarctica, a research team led by Lund University in Sweden...

Greenhouse gases were the main driver of climate change in the deep past

Greenhouse gases were the main driver of climate throughout the warmest period of the past 66 million years,...

Receding Chilean glacier a sign of accelerating climate change

In the space of just two weeks, two large icebergs broke off the Grey Glacier in Chilean Patagonia—a...

Tiger geckos in Vietnam could be the next species sold into extinction

While proper information about the conservation status of tiger gecko species is largely missing, these Asian lizards are...

The Caucasus without a cap

Global warming has caused the total area of more than 600 Greater Caucasus glaciers to drop by approximately...