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Forest soils in southwestern Germany absorb more methane as climate dries, study finds

Forest soils in southwestern Germany absorb more methane as climate dries, study finds

New Capabilities

Methane uptake rose about 3% a year over up to 24 years—but a US reanalysis disputes the moisture explanation for declines elsewhere.

October 17th, 2026: University of Göttingen publicizes 24-year methane findings

Overview

Updated Oct 21

Forest soils in southwestern Germany are pulling more methane out of the air each year, not less. A study of 13 sites over up to 24 years found absorption rising about 3% annually, the opposite of what several international reviews predicted.

A July 2026 paper in Biogeosciences re-examined two US forest sites and found rainfall and soil moisture explained less than 1% of the variation in methane movement there. The paper's author proposed damage to methane-eating microbes, possibly from nitrogen pollution or invasive earthworms, as an alternative cause. Upland forest soils worldwide remove roughly 22 to 38 million metric tons of methane a year, about 5% of the planet's methane sink.

Why it matters

The debate over why forest methane uptake differs by region decides how much of a brake soils are counted as in climate models.

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Key Indicators

3%
Average annual increase in methane absorption
Rise measured across 13 southwestern German forest sites over up to 24 years.
13
Forest sites measured
Sites across southwestern Germany, with soil gas profiles sampled every two weeks.
24
Years of continuous measurements
Longest monitoring record in the dataset, among the world's most comprehensive.
77%
Decline in forest soil methane uptake, global analysis
A separate global analysis found the opposite trend. A 2018 US study found local declines of 53% to 89%, which it linked to wetter soils; a 2026 reanalysis disputed that cause.
22-38M
Methane absorbed by upland forest soils each year
Estimated at 22 to 38 million metric tons, about 5% of the planet's methane sink, according to a July 2026 Biogeosciences paper.

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People Involved

MM
Martin Maier
Led the study; professor at Göttingen University's Department of Crop Sciences
Active researcher; previously involved in the Baden-Württemberg Forest Research Institute's soil gas monitoring program
VL
Verena Lang
First author of the study
Researcher contributing to the methane absorption analysis

Organizations Involved

University of Göttingen
University of Göttingen
Public research university
Led the methane absorption study

German research university whose Department of Crop Sciences led the 24-year forest methane analysis.
FV
Baden-Württemberg Forest Research Institute (FVA)
State research institute
Co-led the study; operated the soil gas monitoring program

State agency in Freiburg that maintained the long-term soil gas monitoring network across 13 forest sites.

Timeline

2025 October 2026

3 events Latest: October 17th, 2026 · 4 weeks ago

  1. University of Göttingen publicizes 24-year methane findings

    Latest Publication

    The university releases a report via ScienceDaily detailing how drier, warmer conditions boost forest soil methane absorption, challenging prior predictions.

  2. Biogeosciences paper questions moisture explanation for US methane decline

    Research

    A reanalysis of methane measurements from Baltimore and New Hampshire's Hubbard Brook forest found rainfall and soil moisture explained less than 1% of the variation. It proposed damage to methane-eating microbes as an alternative cause.

  3. Study published in Agricultural and Forest Meteorology

    Research

    Lang, Gartiser, Hartmann, and Maier publish analysis of up to 24 years of methane measurements from 13 German forest sites, finding 3% annual absorption increases.

Scenarios

1

German forest methane uptake keeps rising as regional climate dries

Possible Resolves by End of 2028

Discussed by: The study's authors, who argue long-term monitoring is essential to detect gradual shifts

If declining rainfall and warming continue in southwestern Germany, the 13 monitored sites keep absorbing more methane each year. New publications from the University of Göttingen or FVA would confirm the trend extends beyond the current dataset.

2

Global methane budget revises forest soil sink to reflect regional moisture

Possible Resolves by End of 2028

Discussed by: Researchers who note the German results directly contradict the US trend, suggesting region-specific modeling is needed

The Global Carbon Project's next methane budget update incorporates regional soil-moisture effects on forest soil uptake, acknowledging that drier and wetter regions move in opposite directions. This would change how sinks are credited across different climate zones.

3

Global forest soil methane sink keeps shrinking despite German gains

Uncertain Resolves by End of 2028

Discussed by: Researchers behind the US study and earlier meta-analyses concluding forest soil methane uptake is declining

A new global synthesis or major assessment confirms that, on balance, forest soil methane uptake continues to fall worldwide. The German trend is treated as a regional exception driven by local drying, not a pattern that offsets losses elsewhere.

4

Microbial damage, not rainfall, explains US forest methane declines

Uncertain Resolves by End of 2027

Discussed by: The author of a July 2026 reanalysis in Biogeosciences

The reanalysis found rainfall and soil moisture explained less than 1% of methane movement at Baltimore and Hubbard Brook. If microbial damage from nitrogen pollution or invasive earthworms is the cause, US forest declines could persist even as rainfall patterns shift.

Historical Context

2 moments from history that rhyme with this story — and how they unfolded.

2006

Old-Growth Forests Can Accumulate Carbon in Soils (2006)

Researchers led by Zhou et al. found that preserved old-growth forests in southern China accumulated carbon in the top 20 centimeters of soil at an average rate of 0.61 megagrams per hectare per year from 1979 to 2003, based on repeated soil sampling.

Then

The finding directly challenged the prevailing belief that old-growth forests are carbon-neutral, with uptake balanced by respiration.

Now

It supported a new nonequilibrium framework for studying soil carbon dynamics and reshaped how scientists think about mature forests as carbon sinks.

Why this matters now

Like the German methane study, long-term field measurements overturned a widely held assumption in ecosystem ecology that had persisted for decades.

2021

Whole-Soil Warming Experiment (2021)

A conifer forest experiment warmed an entire soil profile 4 degrees Celsius for 4.5 years, causing a 33% loss of subsoil carbon below 20 centimeters and a sustained 30% increase in soil carbon dioxide efflux.

Then

The study provided what its authors called definitive evidence of a positive soil carbon-climate feedback.

Now

It showed warming drives different outcomes at different soil depths, complicating simple predictions about soil responses to climate change.

Why this matters now

The experiment illustrates how soil processes respond to warming in complex, sometimes opposite ways depending on conditions—the same lesson the German methane study draws about regional variation.

Sources

(7)
+1
ScienceDaily Phys.org SciTechDaily Carbon Brief Science Advances Nature World News Science