Record-High Greenhouse Gas Concentrations in 2024: CO₂, CH₄, and N₂O
In 2024, atmospheric concentrations of greenhouse gases—carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O)—reached their highest levels ever recorded, driven by human activities. Carbon dioxide remains the largest contributor to global warming, accounting for approximately 42% of the temperature increase since pre-industrial times (1850–1900), followed by methane at 28% and nitrous oxide at 5%. The remaining 25% is attributed to other contributors like carbon monoxide, black carbon, and chlorofluorocarbons (CFCs).
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| Global concentrations of CO2, Based on data from NOAA |
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| Global concentrations of methane (CH4), Based on data from NOAA |
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| Global concentrations of nitrous oxide (N2O), Based on data from NOAA |
The atmospheric concentrations of these greenhouse gases, driven by human emissions, have reached levels not seen in millions of years. A graph (shown above) tracking their concentrations since 1980 reveals a clear upward trend, with CO₂ levels measured up to September 2024.
Without substantial efforts to reduce greenhouse gas emissions, this trend is expected to continue. Projections suggest that by 2035–2040, CO₂ concentrations could exceed 450 ppm, while CH₄ concentrations may surpass 2000 ppb, further accelerating global warming and its impacts.
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| Arctic and Antarctic daily sea ice extent - US National Snow and Ice Data Center |
Melting Glaciers: A Major Contributor to Global Sea Level Rise
A significant portion of global sea level rise is caused by the melting of glaciers on land. Observations from programs such as GRACE (Gravity Recovery and Climate Experiment) and the World Glacier Monitoring Service (WGMS) provide valuable insights into global glacier mass loss and Greenland's cumulative ice loss, as shown in the image above.
Between September 2023 and August 2024, Greenland alone lost 80 billion tons of ice. Over the past 50 years, it is estimated that approximately 6 trillion tons of ice have disappeared from Greenland, significantly contributing to rising sea levels.
These alarming figures highlight the accelerating pace of ice loss and its profound impact on the global climate system and coastal communities worldwide.
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| Global average sea level rise reconstructed from tide gauge data between 1880 and 2024 |
The combination of melting ice from land and polar regions, thermal expansion of warming seawater, and changes in terrestrial water storage are driving the acceleration of sea level rise. Since 1900, global sea levels have risen by more than 20 cm, with a marked increase in the past 30 years, as shown in the graph above.
Long-term records indicate that the rate of sea level rise has nearly doubled. Between 1993 and 2002, the average annual rise was 2.13 mm, while between 2014 and 2023, it surged to 4.77 mm per year. This accelerating trend underscores the growing impact of climate change on the world's oceans.
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| The world will likely exceed 1.5°C in the coming years without rapid emissions reductions |
Global Temperature Projections for 2025 and the Urgent Need for Carbon Neutrality
In 2024, Earth's average temperature reached the upper range of predictions made earlier in 2023. For 2025, most climate models suggest that it is likely to become the third hottest year on record, following 2024 and 2023. The El Niño event that contributed to the sharp temperature rise in early 2024 has mostly dissipated, and La Niña conditions are expected to emerge, potentially influencing global temperatures.
Given the long-term warming trend driven by human greenhouse gas emissions, the global focus may need to shift from limiting warming to 1.5°C to setting a new target of 2.0°C. Current trends indicate that the 1.5°C threshold could be exceeded by the late 2020s to early 2030s, with global temperatures potentially reaching 2.0°C by 2050 if no significant changes are made.
Achieving carbon neutrality is now more critical than ever to mitigate the impacts of these alarming projections and ensure a sustainable future for the planet.
Photo and content sources: CarbonBrief - State of the climate: 2024 sets a new record as the first year above 1.5C
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