According to measurements from Mauna Loa Observatory in Hawaii, with 410.31 ppm (parts per million), the level of carbon dioxide in Earth’s atmosphere hit a new high in April 2018. This is the highest point for the last 800,000 years.

Last year’s (April 2017) value, 409.00 ppm, was also a record high. As you can see in the graph below, which shows recent monthly mean carbon dioxide measured at Mauna Loa Observatory, Hawaii, it’s a continuing trend.

Monthly mean carbon dioxide at Mauna Loa, Hawaii in the recent years
The graph above shows the recent monthly mean carbon dioxide measured at Mauna Loa Observatory, Hawaii in the last five years. It is published by the National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory Global Monitoring Division.
The last four complete years of the Mauna Loa CO2 (carbon dioxide) record plus the current year are shown. Data are reported as a dry air mole fraction defined as the number of molecules of carbon dioxide divided by the number of all molecules in the air, including CO2 itself after water vapor has been removed. The mole fraction is expressed as parts per million (ppm). Example: 0.000400 is expressed as 400 ppm.
In the above figure, the dashed red line with diamond symbols represents the monthly mean values, centered on the middle of each month. The black line with the square symbols represents the same, after correction for the average seasonal cycle. The latter is determined as a moving average of SEVEN adjacent seasonal cycles centered on the month to be corrected, except for the first and last THREE and one-half years of the record, where the seasonal cycle has been averaged over the first and last SEVEN years, respectively.
The last year of data is still preliminary, pending recalibrations of reference gases and other quality control checks. The Mauna Loa data are being obtained at an altitude of 3400 m in the northern subtropics, and may not be the same as the globally averaged CO2 concentration at the surface.
Image Source

The highest level of atmospheric carbon dioxide reached in the 800,000 years

410.31 ppm is the highest level reached in 800,000 years. We are pretty sure about that: scientists have been studying gas bubbles trapped in glacial ice. By drilling more than 3 kilometers (1.86 miles) deep into the ice sheets over Greenland and Antarctica, scientists can see how temperature and atmospheric carbon-dioxide levels have changed since then. The air bubbles trapped in the ice can tell us the type of greenhouse gases (see notes 1) in the ancient atmosphere.

The ice may also contain dirt or other tiny particles that tell us when there were past volcanic eruptions. So, each ice core acts as an atmospheric time capsule. With the valuable information that they contain, scientists can compare the climate conditions of the past to today. By studying the climate of the past, scientists also can make predictions about the future. The last eight glacial cycles cover 800,000 years, and researchers are fairly confident that CO2 levels haven’t been higher than today’s levels in all that time.

Greenhouse Gas Emissions
To limit global warming to 1.5-2 °C by 2100 (relative to pre-industrial temperatures), we’d need an urgent and rapid reduction in global greenhouse gas emissions. Image: PX Here

In fact, the new record may hold even further back in history. A report published last year by the World Meteorological Organization revealed that 2016’s CO2 levels were higher than they’d ever been for at least the past three million years. And, in the following two years, we broke that record consecutively.

According to the report, the last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago, the temperature was 2-3°C warmer and the sea level was 10-20 meters (30-60 feet) higher than now. So, we can expect the oceans to rise substantially in the next 80-150 years. In fact, we already know that the global sea-level rise has been accelerating in recent decades. Say goodbye to Miami, Venice, and all coastal cities!

Global sea level rise: tidal Flooding in Miami. October 17, 2016
October 17, 2016, tidal flooding on a sunny day during the “king tides” in Brickell, Miami that peaked at four feet MLLW. Tidal flooding is getting worsened because of the global sea-level rise. Rather than increasing steadily, global sea-level rise has been accelerating in recent decades. If this trend continues, by the year 2100, sea-level rise will be around 65 cm (25.6 in), twice as big as previously thought. This is more than enough to cause significant problems for coastal cities. Image: Wikipedia
While it’s true that Earth’s temperatures and carbon dioxide levels have always fluctuated, the reality is that humans’ greenhouse emissions since the industrial revolution have put us in uncharted territory.
Written by Dr. Benjamin Henley and Assoc Prof Nerilie Abrams.
Animated and edited by Wes Mountain for The Conversation.
Music: Kevin Macleod – Faster Does It


  1. A greenhouse gas is a gas in an atmosphere that absorbs and emits radiant energy within the thermal infrared range. This process is the fundamental cause of the greenhouse effect (the process by which radiation, from a planet’s atmosphere, warms the planet’s surface to a temperature above what it would be without its atmosphere). The primary greenhouse gases in Earth’s atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Without greenhouse gases, the average temperature of Earth’s surface would be about -18 °C (0 °F), rather than the present average of 15 °C (59 °F).


  • “Trends in Atmospheric Carbon Dioxide” on National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory Global Monitoring Division website
  • “CO2 Levels Have Reached a Scary New Milestone, But You’re Gonna Ignore It Anyway, Aren’t You” on Science Alert
  • “Sorry Earth, Carbon Dioxide not this bad in 800,000 Years. Humans, 410 parts per million, nice job!” By Michael K. Spencer on
  • “Greenhouse gas concentrations surge to new record” on World Meteorological Organization webpage
M. Özgür Nevres

Leave a comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.