CO₂ Emissions Reach New Heights in 2025 Despite Slight Relief from Land-Use Sector

Global carbon dioxide (CO₂) emissions from fossil fuels and cement are projected to rise 1.1% in 2025, reaching an unprecedented 38.1 billion tonnes (GtCO₂), according to the latest Global Carbon Budget released by the Global Carbon Project. Despite this increase, total global CO₂ emissions will remain broadly unchanged compared to 2024 because emissions from land-use change—primarily deforestation—are expected to fall by nearly 10%.

The fall in land-use emissions is attributed largely to improved forest management and declining deforestation rates in South America, offering a brief reprieve in an otherwise alarming trend. The newly released 20th Global Carbon Budget report highlights that the land carbon sink—the amount of CO₂ absorbed naturally by plants and soils—has rebounded to pre-El Niño levels after two unusually weak years.

However, a companion study published in Nature by the same research team reveals a more concerning long-term trajectory: climate change is steadily eroding the strength of natural land carbon sinks.

Climate change weakening land sinks, turning forests into sources

According to the Nature study, the natural land CO₂ sink is significantly smaller than previously estimated. Climate change has reduced sink efficiency enough to contribute 8.3 ± 1.4 ppm to the atmospheric CO₂ rise since 1960—about 8% of the total increase.

The research finds that:

• Large parts of Southeast Asia

• Vast regions of the Amazon and South American tropics

have already shifted from being net carbon sinks to net carbon sources, driven by warming, extreme weather, and deforestation. This transition underscores the urgent need to halt forest loss and limit global temperature rise.

Global emissions trends: Who is rising, who is slowing?

The 2025 assessment shows shifting patterns in national emissions:

• China & India: Emission growth expected to slow significantly compared with the past decade.

• United States & European Union: Emissions are projected to increase in 2025 after several years of decline.

• Global land-use emissions: Expected to drop nearly 10%, providing the only meaningful counterbalance to rising fossil emissions.

Overall, total CO₂ emissions (fossil + land-use) have grown at a slower pace—0.3% per year over the last decade compared to 1.9% per year in the decade before.

Carbon budgets: 1.5°C threshold nearly crossed

The new budget issues a stark warning:

• The remaining carbon budget for 1.5°C warming is almost completely spent—just four years at today’s emission levels.

• Budgets for 1.7°C and 2°C would be depleted in 12 and 25 years, respectively.

• Atmospheric CO₂ concentrations are set to hit 425.7 ppm in 2025, 52% above pre-industrial levels.

Despite the Paris Agreement being in force for a decade, fossil CO₂ emissions continue to rise, pushing concentrations to 423 ppm in 2024 and driving human-induced warming to 1.36°C—dangerously close to surpassing the 1.5°C threshold.

The road ahead: Better monitoring and stronger action

The report stresses that accurate understanding of natural CO₂ sources and sinks is essential for effective climate policy. Current mismatches between reported emissions and measured sinks have hindered the ability to track progress reliably.

Researchers warn that only immediate action—combined with a sharp reduction in fossil fuel use and protection of global forests—can prevent further weakening of Earth’s natural carbon buffers.

The writer of this article is Dr. Seema Javed, an environmentalist & a communications professional in the field of climate and energy