New Zealand scientists have uncovered a potentially alarming shift in global methane emissions, with massive wildfires now leaving a measurable fingerprint in the atmosphere — raising concerns that climate change could be triggering a dangerous cycle of further warming.
Research led by Earth Sciences New Zealand, published as part of the World Meteorological Organization’s annual Greenhouse Gas Bulletin, has revealed a significant change in the sources of methane entering the atmosphere.
The findings come as global concentrations of carbon dioxide, methane and nitrous oxide reached unprecedented levels in 2025, reinforcing concerns about the long-term consequences of human-induced climate change.
Scientists say the latest evidence could represent an early warning that rising global temperatures are beginning to alter the Earth’s natural systems in ways that could accelerate future warming.
WILDFIRES LEAVE A GLOBAL FINGERPRINT
Researchers examining the chemical composition of atmospheric methane discovered a sharp increase in the proportion associated with wildfires between mid-2023 and 2025.
By analysing methane isotopes, which act as molecular fingerprints identifying different emission sources, scientists were able to distinguish methane released by burning vegetation from methane produced through biological processes such as wetlands and agriculture.
The analysis found that the relative contribution of methane associated with biomass burning increased significantly during the observation period.
Scientists believe the shift was largely driven by record-breaking wildfires across North America and the Amazon during 2023 and 2024.
Those fires occurred alongside widespread hot and dry conditions, compounded by an El Niño weather pattern that increased wildfire risks while reducing methane emissions from some wetlands.
The combination produced a noticeable change in the global methane isotope record.
Dr Peter Sperlich, an atmospheric scientist with Earth Sciences New Zealand and lead author of the methane isotope analysis, says the findings demonstrate the extraordinary scale of recent wildfires.
For the first time, wildfire-related methane emissions have become sufficiently significant to produce a detectable change in the global atmospheric isotope record.
Although the relative contribution from wildfire sources had almost returned to its earlier level by the end of the observation period, researchers say the temporary increase may be an important warning of future climate risks.
A DANGEROUS CLIMATE FEEDBACK LOOP?
The findings raise concerns about the possibility of a climate feedback loop.
As greenhouse gas emissions drive global temperatures higher, hotter and drier conditions can increase the frequency and severity of wildfires.
Those fires release additional greenhouse gases, including methane and carbon dioxide, which can contribute to further warming.
That warming may then create conditions for even more extensive fires.
Scientists caution that the latest observations do not establish that a permanent feedback loop has begun, but they demonstrate how large-scale environmental changes can influence atmospheric greenhouse gas concentrations.
Earth Sciences New Zealand Chief Scientist for Changing Atmosphere, Dr Sara Mikaloff-Fletcher, says the research reinforces the urgency of reducing human-caused emissions.
She warns that increasingly severe wildfires could become an additional source of greenhouse gases, making efforts to stabilise the climate more difficult.
The findings also highlight the importance of understanding how climate change affects natural systems, rather than focusing solely on emissions from industry, transport and agriculture.
CARBON DIOXIDE GROWTH HAS TRIPLED SINCE THE 1960s
The World Meteorological Organization’s latest Greenhouse Gas Bulletin also reveals the accelerating accumulation of carbon dioxide in the atmosphere.
During the 1960s, atmospheric carbon dioxide concentrations increased by an average of approximately 0.8 parts per million annually.
Between 2011 and 2020, that average annual increase had climbed to 2.4 parts per million, three times the earlier rate.
Between 2024 and 2025 alone, the global average carbon dioxide concentration increased by another 2.8 parts per million.
The findings confirm that greenhouse gases continue accumulating in the atmosphere, trapping additional heat and contributing to long-term global temperature increases.
Methane is particularly important because it is a powerful greenhouse gas, despite remaining in the atmosphere for a shorter period than carbon dioxide.
Reducing methane emissions can therefore play an important role in limiting near-term warming.
WHAT DOES THIS MEAN FOR AOTEAROA?
The research has particular significance for New Zealand, where methane represents a major component of the country’s greenhouse gas emissions profile.
According to Earth Sciences New Zealand, methane accounts for more than half of the country’s emissions, with major sources including livestock farming and waste management.
Researchers are developing new technologies to help farmers, landfill operators and wastewater treatment facilities more accurately identify and measure methane emissions.
These include highly sensitive monitoring systems mounted on drones and vehicles, combined with isotope analysis to distinguish between different methane sources.
For example, the technology could help determine whether methane detected near a farm originates from livestock and agricultural operations or from neighbouring wetlands.
More accurate measurement could support efforts to reduce emissions and verify whether mitigation initiatives are working.
The research also draws on measurements from New Zealand’s atmospheric monitoring stations at Lauder in Central Otago and Baring Head near Wellington, alongside observations from Arrival Heights in Antarctica.
These facilities contribute valuable information to international efforts to monitor changes in the global atmosphere.
MĀORI COMMUNITIES ON THE FRONTLINE OF CLIMATE CHANGE
For Māori communities, the findings reinforce concerns about the growing impacts of climate change on whenua, waterways, coastal settlements and traditional food-gathering areas.
More frequent droughts, extreme weather events, changing rainfall patterns and increasing wildfire risks can place additional pressure on Māori landowners, farmers, marae and rural communities.
The potential for climate change to intensify natural greenhouse gas emissions also raises wider questions about environmental stewardship and the long-term protection of natural resources.
For iwi and hapū managing whenua, forests, wetlands and agricultural enterprises, improved emissions monitoring and stronger climate resilience planning could become increasingly important.
The research highlights the interconnected relationship between human activity, the natural environment and the changing climate.
SCIENTISTS SAY THE TIME TO ACT IS NOW
The World Meteorological Organization releases its Greenhouse Gas Bulletin annually ahead of international climate negotiations, providing governments and researchers with authoritative information about the changing composition of the atmosphere.
The latest findings show that despite international commitments to reduce emissions, the world’s major greenhouse gases continue to reach record concentrations.
Researchers say the emerging relationship between climate-driven wildfires and methane emissions makes reducing fossil fuel emissions and other human-caused greenhouse gases even more urgent.
The concern is that as global temperatures continue rising, natural processes could increasingly contribute to the problem, making future warming harder to control.
The message from New Zealand scientists is clear: climate change is not simply warming the planet — it may also be changing the natural systems that regulate its atmosphere.
And while the wildfire-related methane increase observed in this study was temporary, the potential for more frequent and intense fires presents a warning that cannot be ignored.
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