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The extreme hot and dry conditions of 2023 reduced soil respiration and enhanced net forest carbon sequestration in Canada, offsetting wildfire emissions, according to satellite-based and in situ observations of CO₂ fluxes.

A bookkeeping approach shows that disturbed tropical humid forests experienced net aboveground carbon loss during 1990–2020, primarily driven by small but persistent deforestation clearings owing to persistent land-use conversion without forest regrowth.

Atmospheric CO₂ levels were much lower during the last glacial maximum than in the pre-industrial period. Ice-core data and biogeochemical modelling suggest that difference is partly due to the greater mass of inert carbon in glacial terrestrial biomes.

Using systematic satellite observations of land surface temperature and soil moisture during soil dry-downs, the spatially-explicit global distribution of the critical soil moisture threshold of plant water stress and its drivers is uncovered.

Ecosystems accumulate carbon for several days after moisture pulses, but this benefit fades as soil dries and heat stress intensifies, according to an analysis that uses carbon flux-tower observations, Earth system models, machine learning, and satellite images.

Heat and moisture stress can reduce carbon uptake by forests. Here, the authors quantify this effect for the extreme 2022 European summer drought. The widespread reduction of photosynthesis exceeded the large local carbon release by intense fires.

Soil carbon loss from human agriculture-related land use in the dry tropics largely offsets gains in northern lands, leading to a small net sink of 0.34 ± 0.30 PgC yr⁻¹ at a global scale.

Trends in global H₂ sources and sinks are analysed from 1990 to 2020, and a comprehensive budget for the decade 2010–2020 is presented.

Global leaf area has increased over the past four decades, raising hopes for its role in mitigating climate change through carbon uptake and cooling effects. This study shows that vegetation cover change, particularly tree cover gain in the Northern Hemisphere, plays a significant role in driving the greening trend.

A re-assessment of the global carbon budget shows the natural land sink is substantially smaller than previously estimated, indicating emerging impacts of climate change on the evolution of the carbon sinks.

There is no single correct procedure for the attribution of responsibility for growth in atmospheric CO₂ concentrations because results are closely dependant on how carbon sinks are accounted for and linked to emissions. Now research that uses two different approaches—one assuming geographically constrained sinks and the other unconstrained—unambiguously attributes the largest share of the historical increase in CO₂ to developed countries.

It is widely acknowledged that some form of carbon capture will be necessary to limit global warming to less than 2 °C, but to what extent remains unclear. Here, using climate-carbon models, the authors quantify the amount of negative emissions and carbon storage capacity required to meet this target.

Accelerated storage of terrestrial carbon during the slow warming period (1998–2012) can be predominantly attributed to lower land-use emissions due to decreased tropical forest loss and increased afforestation in the northern temperate regions.

New high-resolution datasets for the Amazon forest show a loss of carbon in 2010-2020, with gains by forest growth outweighed by losses by deforestation and degradation. Human losses intensified over time, reinforcing the need for stronger policies.

Accurate tree cover mapping is vital for fighting climate change and land degradation. This high-resolution study reveals that 17% of pan-tropical tree cover was previously undetected, with over half of recent losses linked to human activities.

Atmospheric carbon dioxide levels rose at the end of the last glacial period, but the sources of this carbon are uncertain. Ice-core data and carbon-cycle modelling suggest that the disappearance of a terrestrial inert carbon pool may have contributed to the rise.

Modelling of the evolution of atmospheric methane emissions from the 2022 Nord Stream subsea pipeline leaks shows that the event emitted the largest recorded amount of methane from a single transient event.

Drought, fires, and human activities have reversed the accumulation of live biomass carbon in the Northern Hemisphere, with total biomass shifting from a positive to a negative trend around 2016.

Fire emissions in the Amazon and Cerrado biomes are mainly produced from smouldering combustion of woody debris, according to observationally constrained fire emissions inventories.

Robust quantification of carbon dioxide fluxes from land use is critical for guiding climate change mitigation efforts and for improved understanding of the global carbon cycle. This Perspective explores the origins of uncertainties and discrepancies in established estimation approaches and considers strategies to improve, translate and harmonize flux estimates.

The COVID-19 pandemic has stopped many human activities, which has had significant impact on emissions of greenhouse gases. Here, the authors present daily estimates of country-level CO₂ emissions for different economic sectors and show that there has been a 8.8% decrease in global CO2 emissions in the first half of 2020.

Tropical aboveground biomass carbon is a crucial, yet complex, component of the terrestrial C budget. Here remote observations demonstrate that fire emissions and post-fire recovery in non-forested African biomes dominate the interannual variability of aboveground biomass carbon, which acts as a moderate net C sink.

Growing biomass carbon stock in China between 2001 and 2020 is driven by conservation and anthropogenic expansion of woodland.

Phosphorus (P) limitation is pervasive in tropical forests. Here the authors analyse the dependence of photosynthesis on leaf N and P in tropical forests, and show that incorporating leaf P constraints in a terrestrial biosphere model enhances its predictive power.

The authors construct a process-based hunter-gatherer population model embedded within a global terrestrial biosphere model that reveals a strong effect of growing season length on population density via diet composition.

Bottom-up and top-down approaches are used to quantify global nitrous oxide sources and sinks resulting from both natural and anthropogenic sources, revealing a 30% increase in global human-induced emissions between 1980 and 2016.

This study provides a nuanced understanding of the trade-offs and synergies between carbon sequestration goals and water security, and offers a data–model integrated framework to guide ecosystem restoration strategies under water resource constraints.

Carbon loss from forests occurs through deforestation or the degradation of existing forest. The loss of forest area in the Brazilian Amazon was higher in 2019 than following drought and an El Niño event in 2015, yet degradation drove three times more biomass loss than deforestation from 2010 to 2019.

Recent analyses have suggested that tree cover in non-forest ecosystems may be much higher than expected. Here, the authors map tree cover down to the individual tree level for the entire continent of Africa and find that almost 30% is found outside areas classified as forests.

Drivers of spatial differences in leaf phenology are not as widely studied as temporal differences. Here the authors show that the spatial variation of leaf unfolding in 8 deciduous tree species in Europe can be explained by local adaptation to long-term mean climate conditions.

Using both bottom-up and top-down approaches, the record high increase in the methane growth rate in 2020 is attributed mainly to emissions from wetlands, which have been exacerbated by a warmer and wetter climate, and to the reduced atmospheric methane sink, in response to emissions reduction of air pollutants during COVID-19 lockdowns.

Changes in the leaf area index alter the distribution of heat and moisture. The change in energy partitioning related to leaf area, increasing latent and decreasing sensible fluxes over the observational period 1982–2016, is moderated by plant functional type and background climate.

A decade of satellite observations suggests that old, degraded and deforested tropical forests are almost carbon neutral whereas northern young forests are the biggest contributor to the rising amount of carbon stored globally in vegetation.

Atmospheric methane concentrations are increasing and a process-based model now estimates greater methane emissions from wetlands since 2007 than previous studies. Substantial increases in 2020 and 2021 contributed to record-high growth rates in the atmospheric methane burden.

Afforestation and reforestation programs aimed at enhancing carbon sequestration may have unintended effects on non-forest ecosystems and biodiversity. Here the authors use remote sensing and land surface modelling to quantify trade-offs between tree planting and wetland conservation in China

There are big uncertainties in the contribution of irrigation to crop yields. Here, the authors use Bayesian model averaging to combine statistical and process-based models and quantify the contribution of irrigation for wheat and maize yields, finding that irrigation alone cannot close yield gaps for a large fraction of global rainfed agriculture.

Low-frequency passive microwave data (L-VOD) allow quantification of biomass change in sub-Saharan Africa between 2010 and 2016, revealing climate-induced carbon losses, particularly in drylands.

The northern high latitude permafrost region has been an important contributor to the carbon sink since the 1980s. A new study finds that as tree cover increases, respiratory CO2 loss during late-growing season offsets photosynthetic CO2 uptake and leads to a slower rate of increasing annual net CO2 uptake.

Aiming for declining global temperatures can limit long-term climate risks compared with a mere stabilization of global warming, including sea-level rise and cryosphere changes.

Wind speeds have reduced globally over land since the 1980s. In situ data show that this reversed around 2010, with natural ocean–atmosphere variability thought to drive the wind speed changes, as well as a 17% increase in potential wind energy for 2010–2017 and a boosted wind power capacity factor.

Using global flux tower observations, the authors show that atmospheric dryness always reduces photosynthesis, whereas soil dryness can increase photosynthesis if soil water stores are sufficient.