Large-scale environmental changes, including climate change, biogeochemical cycles, land use change, sea level rise, and the impacts of human activities on Earth system processes
23 papersThis study compared greenhouse gas emissions from a conventional pasture-based beef system (CONV) and a partial-confinement system (ALT). The CONV system was found to be a net carbon sink due to perennial grassland sequestration, while the ALT system was a net source of emissions. This highlights that the design of beef production systems significantly influences their environmental footprint.
This study systematically links historical heatwaves to climate change and quantifies the contributions of individual carbon majors (fossil fuel and cement producers). It finds that all 213 heatwaves analyzed were made more intense and likely due to climate change, with carbon majors contributing to roughly half of the observed increase in heatwave intensity since the pre-industrial era.
This study uses field and lab data along with ocean ecosystem models to predict that the important ocean algae *Prochlorococcus* might decline significantly by the end of the century due to warming tropical waters. The study also suggests that even if *Prochlorococcus* adapts to warmer temperatures, it may still decline in the hottest regions, and this decline may have wider impacts on ocean ecosystems.
This study estimates a "prudent planetary limit" for storing carbon dioxide (CO2) underground to be around 1,460 gigatons, much lower than previous estimates. This limit is based on avoiding various risks, like earthquakes and leaks into water supplies, and suggests we'll need to cut emissions drastically to stay within it.
The study projects a significant increase in coastal flooding for Small Island Developing States (SIDS) by 2100, even under a 1.5°C warming scenario. Annual flood damages could rise more than tenfold, potentially exceeding a substantial percentage of some nations' GDP. The model does have limitations, including static assumptions about ecosystem protection and not fully capturing all local factors, which would increase the flooding more than currently predicted.
Laboratory cultures of phytoplankton revealed differences in carbon allocation among taxa and growth phases, with higher production of a long-lasting carbon compound (CRAM) during the growth season. Incorporating these findings into a global model improved predictions of dissolved organic carbon (DOC) concentrations, suggesting that changes in phytoplankton communities and bloom durations can significantly reshape the ocean's carbon cycle.
Using a simplified two-box model, this paper argues that the adjustment time of CO2 in the atmosphere is less than its residence time, implying that anthropogenic CO2 disappears within 5 years. This contradicts the established scientific consensus about the long-term impact of CO2 emissions. The model's oversimplification and unvalidated assumptions raise serious concerns about the validity of this conclusion.
Climate models project that a large portion of the Amazon rainforest could experience severe decline by the end of the 23rd century under a high greenhouse gas emission scenario. Key factors contributing to this decline are rising temperatures, decreasing rainfall, and land-use changes, specifically the conversion of forest to pasture or cropland. The decline is projected to be gradual, spanning over a century, eventually leading to a temporary shift from a carbon sink to a carbon source in the 22nd century before returning to near-neutral conditions by the 23rd century.
The 2020-21 drought in the U.S. Southwest saw record low precipitation and the third-highest temperatures since 1895. While natural climate variations were the primary driver, human-caused warming intensified the drought by increasing evaporation. The drought is expected to persist into 2022, possibly longer, especially as climate change continues to exacerbate future drought risk.
This study claims that reducing ship sulfur emissions unexpectedly accelerated global warming by reducing the cooling effect of aerosols, a "Faustian bargain." However, the analysis relies on correlating decreased ship emissions with a warming trend, assuming causation without sufficiently controlling for other factors. The paper's ship aerosol forcing estimation also contradicts several other studies that found much smaller effects.
Increased glacial meltwater in Greenland fjords enhances phytoplankton productivity due to nutrient upwelling, although the impact on overall ocean carbon uptake is limited due to counteracting changes in water chemistry. The study utilized a high-resolution model, but some biases related to sea ice cover and nutrient concentrations were noted. The findings highlight the complex interplay of physical and biological factors in glacial fjord ecosystems and their response to climate change.
Wildfires in California are starting earlier, driven by climate change and natural climate variability. While natural variability played a significant role, anthropogenic warming advanced fire season onset in most ecoregions, especially in the north, primarily due to warmer temperatures and earlier snowmelt. Southern California shows less of this trend due to fuel limitations and more complex climate influences.
This study used satellite data to compare temperature trends in ten major cities across seven continents, finding that urban areas are generally warming, especially at night, and that green spaces have a cooling effect. Industrial areas and airports were hotspots, while green spaces and water bodies tended to be cooler.
Global ecosystem restoration has limited potential for climate change mitigation, offsetting only a small fraction of anthropogenic emissions, even under optimistic scenarios. Restoration efforts are more impactful when prioritizing biodiversity, local climate adaptation, and the resilience of ecosystem services, rather than solely focusing on carbon sequestration.
Key climate indicators show accelerated warming trends, with the Earth's energy imbalance increasing and greenhouse gas emissions remaining at historic highs. While the record-breaking temperature in 2024 was influenced by the El Niño event, the overall warming trend is a cause for concern, exceeding the previously estimated rate of human-induced change.
This study used satellite data to analyze land surface temperature trends in ten major cities across seven continents from 2001 to 2021, finding an overall warming trend, especially at night. Urban heat islands are intensified by industrial zones and airports, but green spaces and water bodies offer significant cooling effects, highlighting the importance of urban greening and climate-responsive urban planning.
This study estimates that AI applications could reduce global emissions by 3.2-5.4 GtCO2e annually by 2035 across the power, food, and mobility sectors. However, this estimate is based on limited assumptions and does not consider the full range of economic interconnections and potential rebound effects. These reductions would primarily come from transforming complex systems, accelerating technology discovery, and nudging behavioral change.
The study defines safe and just Earth system boundaries for various domains like climate, biosphere, water, and nutrients. It finds that seven of eight globally quantified safe and just ESBs are already exceeded, calling for a transformative change across sectors to ensure human well-being and Earth system stability.
Global urban land is projected to expand rapidly until the 2040s, primarily on current croplands, leading to a 1-4% decline in global crop production. This translates to an annual food supply loss equivalent to the needs of 122-1389 million people, highlighting the importance of managing urban development for food security.
The study reveals that global land use change has affected nearly a third of the Earth's land surface (32%) from 1960 to 2019, significantly higher than earlier estimates. This extent of change, equivalent to twice the size of Germany annually, reveals geographically diverging trends, with forest gain in the Global North and deforestation alongside agricultural expansion in the Global South, patterns linked to global trade and other drivers.
This paper describes the creation of version 4 of the Climatic Research Unit gridded Time Series (CRU TS) dataset, a global land surface climate dataset on a 0.5-degree grid, spanning 1901-2018 and updated annually. Key improvements include increased station observations, a new interpolation method using angular-distance weighting, and improved traceability through enhanced metadata.
Global methane emissions for 2008-2017 were estimated at 576 Tg CH4 yr⁻¹ by atmospheric inversions, with about 60% attributed to anthropogenic sources. Bottom-up approaches estimated higher emissions (737 Tg CH4 yr⁻¹), with a significant discrepancy attributed to uncertain natural emissions, especially from inland waters. The study highlights the need for improved mapping and process-based modeling of inland water emissions, better assessment of methane sinks, and enhanced partitioning of sources using top-down models.
A massive die-off of approximately 62,000 common murres occurred from 2015-2016, coinciding with the most powerful marine heatwave on record in the Northeast Pacific. The study estimates total mortality to be near one million birds, with the majority of deaths attributed to starvation and multiple reproductive failures observed across murre colonies.