🥵 CO₂ concentrations in the atmosphere have reached new records despite the relative stabilization of emissions, with human carbon emissions stagnating at around 10.2 GtC per year, but natural carbon sinks (forests, soils, oceans) they can no longer absorb such huge amounts of CO₂. The year 2024 brought a year-on-year increase in atmospheric CO₂ of 3.5 ppm (from 420.5 ppm to 424 ppm), the fastest jump in the history of measurements, and it was also found that intensified fires and widespread droughts significantly weakened the biosphere's capacity to absorb carbon.

1. Stabilization of emissions vs. growth of concentration

Human CO₂ emissions from fossil fuels and land-use change have averaged over the past decade 0.6 % per year, down from 2 % in the previous decade. Nevertheless, annual emissions are still record highs 10.2 GtC (37.4 GtCO₂) in 2024 (Global Carbon Budget). However, atmospheric CO₂ concentration increased on average by 2.4 ppm/year over the past decade and jumped by 2024 3.5 ppm on the 424 ppm, which is more than 50 % more than pre-industrial levels (~280 ppm) (NOAA, EarthSky).

2. Carbon sink analogy

• Faucet (emissions): Burning coal, oil, gas, and deforestation adds carbon to the atmosphere.
• Runoff (natural catchments): plants, soils and oceans absorb about half of the emissions annually (50 %) (NOAA).
  If the carbon input (emissions) is greater than the sink (natural sinks), the “bathtub” (the atmosphere) fills up faster.

3. Weakened natural interceptions

3.1. Large-scale fires

Large fires in Canada (2023) and South America (2024) released millions of tons of carbon that would otherwise have remained locked up in biomass (Cosmos).

3.2. Extremely dry

The year 2024 saw severe droughts in the Northern Hemisphere, which reduced photosynthesis activity and the ability of soils to store carbon (NOAA).

3.3. Ocean capture in change

The oceans, which absorb nearly 25 % of CO₂ emissions, are seeing a decline in efficiency due to warming and circulation changes (gml.noaa.gov).

4. Implications and challenges

• Risk of accelerated warming: If the outflow from the previously naturally absorbing biosphere continues to decline, the atmosphere will fill even faster.
• Emission reduction lever: The only sure way to decrease concentration is sharp reduction in emissions CO₂ below the capacity of natural sinks (Global Carbon Budget).

5. New findings and recommendations

• CSIRO model: It predicts that only when emissions are reduced below certain thresholds will we begin to observe a long-term decline in atmospheric CO₂ (ESSD).
• CDR technologies: Direct air capture (DAC) and bioenergy with CCS achieve lower costs and higher carbon removal rates (globalcarbonproject.org).
• Ecosystem protection: Substantially improving the resilience of forests, wetlands and soils to fires and droughts can increase their storage capacity.

Our “bathtub” is still filling up because the emissions tap is left too open. The time for change is now – significant emissions reductions, restoration of natural sinks and development of CDR technologies are essential to stabilize our climate and secure the future of the planet. Spring