Atmospheric CO₂ fluctuations point to changes in fossil fuel emissions plus natural and perturbed variations in the natural carbon cycle. One unstudied source of variability is the stratosphere, where the influx of aged CO₂-depleted air can cause surface fluctuations. Using modeling and, separately, scaling the observed N₂O variability, I find that stratosphere-driven surface variability in CO₂ is not a significant uncertainty (at most 10 % of the observed interannual variability).

Climate change has multiple effects on Baltic Sea species, communities and ecosystem functioning. Effects on species distribution, eutrophication and trophic interactions are expected. We review these effects, identify knowledge gaps and draw conclusions based on recent (2010–2021) field, experimental and modelling research. An extensive summary table is compiled to highlight the multifaceted impacts of climate-change-driven processes in the Baltic Sea.

Gaining a complete understanding of extreme weather, from its physical drivers to its impacts on society, is important in supporting future risk reduction and adaptation measures. Here, we provide a review of the available scientific literature, knowledge gaps and key open questions in the study of extreme weather events over the vulnerable eastern Mediterranean region.

The deployment of bioenergy crops for capturing carbon from the atmosphere facilitates global warming mitigation via generating negative CO₂ emissions. Here, we explored the consequences of large-scale energy crops deployment on the land carbon cycle. The land-use change for energy crops leads to carbon emissions and loss of future potential increase in carbon uptake by natural ecosystems. This impact should be taken into account by the modeling teams and accounted for in mitigation policies.

To understand the dynamics of a coupled human and natural system (CHANS) and promote its sustainability, we propose a conceptual pattern–process–service–sustainability cascade framework. The use of this framework is systematically illustrated by a review of CHANS research experience in China's Loess Plateau in terms of coupling landscape patterns and ecological processes, linking ecological processes to ecosystem services, and promoting social–ecological sustainability.

The effect of the marine biogeochemical variability upon the South Asian regional climate has been investigated. In the experiment where its full impact is activated, the average sea surface temperature is lower over most of the ocean. When the biogeochemical coupling is included, the main impacts include the enhanced phytoplankton primary production, a shallower thermocline, decreased SST and water temperature in subsurface layers.

We comprehensively investigate historical GPP trends based on five kinds of GPP datasets and analyze the causes for any discrepancies among them. Results show contrasting behaviors between modeled and satellite-based GPP trends, and their inconsistencies are likely caused by the contrasting performance between satellite-derived and modeled leaf area index (LAI). Thus, the uncertainty in satellite-based GPP induced by LAI undermines its role in assessing the performance of DGVM simulations.

Uncertainty within climate model projections on inter-annual timescales is largely affected by natural climate variability. Emulators are valuable tools for approximating climate model runs, allowing for easy exploration of such uncertainty spaces. This study takes a first step at building a spatially resolved, monthly temperature emulator that takes local yearly temperatures as the sole input, thus providing monthly temperature distributions which are of critical value to impact assessments.

Reconstruction and explanation of past climate evolution using proxy records is the essence of paleoclimatology. In this study, we use dimensional analysis of a dynamical model on orbital timescales to recognize theoretical limits of such forensic inquiries. Specifically, we demonstrate that major past events could have been produced by physically dissimilar processes making the task of paleo-record attribution to a particular phenomenon fundamentally difficult if not impossible.

We explore the long-term dynamics of Earth's climate and carbon cycles under a pair of contrasting scenarios to the year 2300 using six models that include both climate and carbon cycle dynamics. One scenario assumes very high emissions, while the second assumes a peak in emissions, followed by rapid declines to net negative emissions. We show that the models generally agree that warming is roughly proportional to carbon emissions but that many other aspects of the model projections differ.

We modelled water budget developments of viticultural growing regions on the spatial scale of individual vineyard plots with respect to landscape features like the available water capacity of the soils, slope, and aspect of the sites. We used an ensemble of climate simulations and focused on the occurrence of drought stress. The results show a high bandwidth of projected changes where the risk of potential drought stress becomes more apparent in steep-slope regions.

Global climate models suggest that droughts could worsen over the coming century. In mountain basins with glaciers, glacial runoff can ease droughts, but glaciers are retreating worldwide. We analyzed how one measure of drought conditions changes when accounting for glacial runoff that changes over time. Surprisingly, we found that glacial runoff can continue to buffer drought throughout the 21st century in most cases, even as the total amount of runoff declines.

Climate change is already affecting weather extremes. In a warming climate, we will expect the cold spells to decrease in frequency and intensity. Our analysis shows that the frequency of circulation patterns leading to snowy cold-spell events over Italy will not decrease under business-as-usual emission scenarios, although the associated events may not lead to cold conditions in the warmer scenarios.

Compound hazards occur when two different natural hazards impact the same time period and spatial area. This article presents a methodology for the spatiotemporal identification of compound hazards (SI–CH). The methodology is applied to compound precipitation and wind extremes in Great Britain for the period 1979–2019. The study finds that the SI–CH approach can accurately identify single and compound hazard events and represent their spatial and temporal properties.

Current world economic production is rising relative to energy consumption. This increase in production efficiency suggests that carbon dioxide emissions can be decoupled from economic activity through technological change. We show instead a nearly fixed relationship between energy consumption and a new economic quantity, historically cumulative economic production. The strong link to the past implies inertia may play a more dominant role in societal evolution than is generally assumed.

A complex PM_2.5 measurement network has been built to investigate transport patterns and cooperative regions in China. Network-based degree measurements are used to reveal the spatial transport pattern of PM_2.5. The study also attempts to investigate the seasonal transport path of PM_2.5. In addition, the cooperation regions of PM_2.5 are quantified according to their synchronicity characteristics. The proposed study can be applied to other air pollutant data, such as ozone and NO_x.