Our planet’s atmospheric concentration of carbon dioxide (CO₂) has broken yet another record. April’s average reading of 413.52 parts per million (ppm) set a new record high, according to Scripps’ Mauna Loa Observatory in Hawaii. This marks yet another high point on the definitively upward trend of the Keeling Curve, a well-known climate change indicator.

To put this rapidly increasing number into perspective, consider that when the observatory was first established in 1958, the CO₂ level was 315 ppm, slightly higher than the pre-industrial level of 280 ppm. Going back even further, ice-core research shows that today’s level of atmospheric CO₂ is unprecedented in the last 800,000 years.

CO₂  is one of the most prevalent greenhouse gases in the atmosphere due to human activities such as the burning of fossil fuels and deforestation. While it is a vital part of our atmosphere’s mix of gases and helps keep the planet from freezing, too much of it causes problems. Simply put, more greenhouse gases in the atmosphere trap more heat and increase the planet’s average temperature.

Since the pre-industrial era, according to the IPCC, Earth’s mean temperature has increased 1°C (1.8°F).  As temperatures rise, long established weather patterns are shifting. Some areas are getting wetter, while others are getting dryer, and coastal communities are feeling the impacts of rising sea levels.

This new CO₂ milestone, therefore, is not good news. The IPCC’s Special Report on Global Warming of 1.5°C released this past autumn clearly states that the impacts of climate change will be greater at a lower degree of warming than previously thought. To avoid the worst of these various impacts, the report says greenhouse gas pollution must be reduced by 45% from 2010 levels by 2030, and slashed to net zero by 2050.

This type of reduction will require massive action and enormous political will.

Credit: Scripps/NOAA