Record Surge in Carbon Dioxide Levels, Casting Doubt on 1.5°C Warming Limit

Last year, carbon dioxide (CO2) levels rose faster than ever before. Scientists warn that this rapid increase puts a key climate target at serious risk. Currently, CO2 concentrations are more than 50% higher than before humans began burning fossil fuels.

Record Fossil Fuel Emissions

In 2023, fossil fuel emissions reached an all-time high. Meanwhile, the natural world struggled to absorb CO2 due to factors like wildfires and droughts. As a result, more CO2 accumulated in the atmosphere, worsening the situation.

1.5°C Goal at Risk

This sharp rise in CO2 threatens the global goal of limiting temperature rise to 1.5°C above pre-industrial levels. Richard Betts from the Met Office explains, “Limiting global warming to 1.5°C would require the CO2 rise to be slowing, but in reality, the opposite is happening.” Therefore, the target is increasingly difficult to achieve.

Human Activities Driving CO2 Growth

The primary cause of the CO2 increase is human activity. Burning coal, oil, and gas, along with deforestation, are key contributors. According to the UN, CO2 levels are now higher than at any point in the past two million years, highlighting the unprecedented nature of this rise.

Fluctuations in CO2 Levels

However, CO2 levels can fluctuate from year to year. The rise in 2023 was partly influenced by the El Niño phenomenon, which warms the Pacific Ocean and disrupts weather patterns. This resulted in a reduced ability of natural carbon sinks, like forests and oceans, to absorb CO2 as they normally would.

Wildfires Contribute to the CO2 Rise

Additionally, wildfires played a major role in releasing more CO2 into the atmosphere. Betts notes, “Even without the boost from El Niño last year, the CO2 rise driven by fossil fuel burning and deforestation would now be outpacing the IPCC’s 1.5°C scenarios.” Therefore, human actions, along with natural events, have compounded the problem.

CO2 Levels Hit New Records

From 2023 to 2024, CO2 levels surged by nearly 3.6 parts per million (ppm), reaching over 424 ppm. This represents the largest increase since measurements began at Mauna Loa Research Station in 1958. Prof. Ralph Keeling comments, “We are moving into uncharted territory faster than ever as the rise continues to accelerate.” Clearly, this rapid increase is cause for concern.

Natural Carbon Sinks Struggle

In addition, natural carbon sinks are becoming less effective. The Arctic tundra is now releasing CO2 due to warming and frequent fires. Similarly, the Amazon rainforest’s capacity to absorb CO2 is weakening because of droughts and deforestation. Betts warns, “It’s an open question, but it’s something we need to keep a close eye on.”

CO2 Levels Predicted to Remain High in 2025

Looking ahead, the Met Office forecasts that CO2 levels will rise more slowly in 2025, partly due to La Niña conditions. However, the levels will still be far from the target needed to meet the 1.5°C goal. Betts concludes, “While there may be a temporary respite with slightly cooler temperatures, warming will resume because CO2 is still building up in the atmosphere.” Thus, the long-term trend remains worrying.