The Power Dynamics of Photosynthesis Drastically Change! The Truth Behind Forest Dominance and Ocean Stagnation: The Future of Earth's Two Major Ecosystems

1. Introduction: The Trending Hashtag

On the night of August 2, science-related social media was suddenly flooded with discussions about <#HiddenClimateBattle>. The spark was an article on ScienceDaily titled "The hidden climate battle between forests and the ocean," which cited a press release from Duke University※1. Shortly after the post, science communicator Ken Gusler tweeted, "A historic moment where land has overtaken the ocean in photosynthesis"※4. Environmental NGOs and climate researchers also reacted, leading to thousands of threads within 24 hours.

"Should we celebrate the 'revenge' of forests? The marine ecosystem is silent!"
—Daily Kos community post※5

2. Overview of the Research

The paper was published in Nature Climate Change. It integrates satellite-derived NPP datasets (three for land and three for ocean) from 2003 to 2021, analyzing land and ocean in the same framework, which is novel※1. Statistical methods were used to extract annual trends and variations, exploring their relationship with environmental factors like temperature, precipitation, and mixed layer depth.

3. Main Results

• Terrestrial NPP: +0.2 GtC/year—Mainly due to warming and increased precipitation in the high latitudes of the Northern Hemisphere, and forest expansion and agricultural intensification in temperate zones.

• Marine NPP: −0.1 GtC/year—Particularly decreased in the tropical Pacific. Nutrient supply reduced due to enhanced stratification from rising sea temperatures.

• Global Total: +0.1 GtC/year—The increase on land outweighs the decrease in the ocean.

4. Why Land Won and Ocean Lost

On land, the extension of the growing season was the primary driver. The CO₂ fertilization effect is also considered a contributing factor. In contrast, in the ocean, the chain of rising sea surface temperatures → enhanced stratification → reduced nutrient supply to the upper layers directly hit plankton. The strength of ENSO events showed significant annual variation, with a temporary recovery during the weak La Niña period after 2015, but it did not last.

5. Reactions on Social Media: Pros and Cons and Emerging Issues

• Proponents (Climate Positive)
  * "Forests have enhanced their function as carbon sinks, there is still hope."

• Cautious Voices (Ocean Focused)
  * "If ocean carbon absorption declines, future warming spikes are unavoidable."

• Systemic View (Integrated Perspective)
  * "The increase on land can be lost in an instant due to logging or fires. Look at both sides!"

Ken Gusler's post received nearly 2,000 retweets, and the hashtag <#OceanSOS> trended※4. In the Daily Kos science community, there was strong concern that "if marine NPP declines, the collapse of the food web will accelerate"※5.

6. Experts and Related Research

In 2023, The Guardian warned of "the year when natural carbon sinks nearly hit zero"※3. Furthermore, a Reuters report on the 30th of this month stated that the carbon absorption of forests within the EU had decreased by 30% compared to the 2010s, jeopardizing the 2050 targets※2. The current results indicate that the dominance of terrestrial areas may not be permanent and highlight the risks of marine decline on the food web.

7. Impact: Food Web, Economy, and Policy

• Tropical Fisheries—Decline in primary production leads to reduced catches, directly impacting the livelihoods of coastal communities.

• Forest Economy—Increased biomass presents opportunities for expanding timber and bioenergy resources. However, overharvesting has adverse effects.

• Climate Policy—"Relying solely on forests for absorption is insufficient," according to an EU report※2. Blue carbon initiatives and nutrient management-based marine conservation are essential.

8. Future Research Challenges

1. Change in NPP Quality—Even if quantity increases, if respiration increases, the net absorption may be offset.

2. Polar Oceans—The Arctic and Antarctic oceans still have significant uncertainties, with potential increases in NPP due to ice reduction and increased light.

3. Human Interventions—Technological interventions like afforestation on land and artificial upwelling devices in the ocean are being discussed, but quantifying ecological side effects is necessary.

9. Conclusion: Towards Global Carbon Management

Even if forests seem to have "won" in the short term, the long-term stagnation of the ocean cannot be overlooked.Land and ocean are two sides of the same coin. To successfully mitigate climate change, it is necessary to monitor both integratively and implement carbon absorption enhancement measures tailored to regional characteristics. The research team's emphasis on establishing a "long-term, cooperative observation system" is indeed the first step.

“Whether the decline in ocean primary production will continue — and how long plants on land can keep compensating — remains a key unanswered question.” (Lead author Zhang)※1

We are being tested on whether we can guide the grand "hidden climate war" woven by green and blue into a scenario of coexistence rather than mere victory or defeat.

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