The claim is made in an April 19 Facebook post which has been shared more than 10,000 times.

It reads: “CO2 in the atmosphere 150 years ago: 0.04%. And today: 0.04%.”

Earth’s atmosphere is made up of several gases including nitrogen, oxygen, methane and CO2.

Historical records constructed from ancient ice cores show the planet’s CO2 levels before the industrial revolution (which began in the mid-1700s) were about 280 parts per million (ppm) or 0.028 per cent, for around 6,000 years of human civilisation.

Analysis from Australian climate scientists (table 6 on page 24), NASA and the European Environment Agency puts the CO2 concentration level for 1873 at approximately 288ppm, or 0.029 per cent.

Data from the National Oceanic and Atmospheric Administration’s Global Monitoring Laboratory shows the global average across 2023 was 419.3ppm, or 0.042 per cent.

Dr Robyn Schofield, an expert in atmospheric chemistry at the University of Melbourne, previously told AAP FactCheck the rise in atmospheric CO2 is due to human activities, such as land clearing and fossil fuel burning.

The Intergovernmental Panel on Climate Change’s Sixth Assessment Report also backs this up, stating observed increases in greenhouse gas concentrations since the 18th century are unequivocally due to human influence (p4).

Professor Brendan Mackey, a climate scientist at Griffith University, agrees the increase in “atmospheric concentration due to human activity is an established scientific fact”.

Australian National University climatology expert Professor Janette Lindesay told AAP FactCheck there is a direct link between human-caused CO2 emissions and rising temperatures.

“Increasing the concentration of greenhouse gases, including carbon dioxide, increases the heat-trapping function of the atmosphere (the enhanced greenhouse effect) and raises the temperature,” she said.

Scientists at NASA’s Goddard Institute for Space Studies say the global average temperature on earth has increased by 1.1C since 1880.