Are the Earth's Lungs Running Out of Breath? Record CO₂ Increase and OCO-2 Shutdown Crisis: On the Eve of the Amazon and Earth's "Carbon Balance" Collapse

1) The Reality of "The Fastest Ever" CO₂ Increase

In 2024, atmospheric CO₂ recorded an unprecedented increase of about 3.7 ppm. This rapid increase is supported by long-term observations from places like Mauna Loa, Hawaii, as well as analyses from satellite observations. The acceleration in the rate of increase indicates not only emissions from fossil fuels but also signs that nature's "absorption mechanisms" are faltering.

2) What Happened in the Amazon

Data assimilation from the satellite OCO-2 revealed that in 2023-24, there was a notable slowdown in carbon absorption in tropical regions, particularly in the Amazon. Indicators such as the weak "light (SIF)" from vegetation photosynthesis and the "greenness" measured by satellites also showed decreased activity during this period. The primary factor was high temperatures, with changes in precipitation and soil moisture also playing a role in other tropical areas. Importantly, even without a strong El Niño, a slight temperature rise on top of drier-than-average conditions can lead to a sudden drop in absorption capacity.

3) Why Even a Weak El Niño Had a Significant Impact

During the strong El Niño of 2015-16, carbon absorption also slowed, but in 2023-24, the impact was significant despite the relatively weak El Niño. The Amazon basin experienced record droughts, with low river levels and widespread forest fires. When trees experience drought stress, their transpiration and photosynthesis decrease, temporarily increasing the proportion of CO₂ that remains in the atmosphere.

4) The Risk Facing the "Eyes of Surveillance": The Issue of OCO-2's Operational Halt

OCO-2, which has been visualizing CO₂ fluxes on a global scale, is still in good condition and could be operational until around 2040. However, recent budget cut proposals have put it at risk of operational halt and mission termination. If lost, our ability to quickly understand changes in the natural carbon cycle would be diminished, making it difficult to distinguish between short-term events (like El Niño) and long-term changes. The operational cost is minimal compared to NASA's overall budget, and the cost-effectiveness is considered high.

5) Digest of Reactions on Social Media

• Reddit (r/space): Criticism such as "wasting hundreds of millions of dollars of investment" and "a setback for Earth observation" has been frequent regarding the conclusion of OCO-2/3. Many discussions include technical and cost-related information.

• Reddit (r/nasa): Posts criticizing "cutting science" and "neglecting Earth observation" have spread. There are also concerns about the impact on education and citizen science.

• X (formerly Twitter): Posts from science communicators and researchers expressing concern over the impact of halting the OCO series as an "expansion of opacity" are prominent. Some voices also pointed out the "poor timing" of weakening monitoring capabilities in a year of rapid CO₂ increase.

※The posts are summaries, and individual views belong to the original posters.

6) Why We Should Strengthen Observations Now

About half of anthropogenic emissions are absorbed by land and sea, but even a temporary drop in that absorption capacity accelerates the increase in atmospheric concentrations. To monitor the health of large ecosystems like the Amazon and the "stamina" of CO₂ absorption, high-frequency and wide-area observations are essential. Satellites complement ground observations and help with early warnings of anomalies (early fire detection, drought spread, absorption capacity decline).

7) What We Can Do

• Policy: Sustained investment in monitoring infrastructure (satellites and ground), measures against forest fires, drought adaptation, and curbing illegal logging.

• Businesses: Disclosure and reduction of supply chain (forest risk), and funding for nature-based solutions (NbS).

• Citizens: Switching to energy-saving and renewable energy, supporting forest conservation organizations, and following scientific information sources.

8) Points of Interest "Next"

• How much will the absorption capacity recover after the rainy season begins in the Amazon basin?

• The impact of El Niño/La Niña transitions after 2025.

• Agreement on support for forests and observation systems at international negotiations (COP30: Belém, Brazil).

• The continuation of OCO-2/3 and the possibility of alternatives and complements through collaboration with private and international organizations.