Coral reefs face unprecedented threats from multiple stressors, many of which are linked to human activities. Some stressors have tipping points that, if exceeded, could cause coral collapse. These include temperatures rising 1.2 °C above pre-industrial levels and atmospheric CO₂ above 350 parts per million. Uncertainty remains for these thresholds; many stressors interact in ways we do not understand. It is important to study these and employ a precautionary principle when planning our actions.

Reducing non-CO₂ greenhouse gases is important alongside CO₂ for climate mitigation. Here, we look at how reducing their emissions compares to reducing CO₂ using an Earth system model. While both types of gases contribute to warming, their regional climate impacts differ. Besides, the carbon cycle responds differently depending on whether climate change is driven by CO₂ or non-CO₂ gases. Considering both types of gases is important for carbon cycle analysis and climate mitigation strategies.

Our study examines potential changes in heatwaves in central Europe due to global warming, using the 2019 summer heatwave as an example. By producing high-resolution storylines, we provide insights into how future heatwaves might spread, how they might persist for longer, and where stronger or weaker temperature increases may occur. This research helps us understand regional thermodynamic responses and highlights the importance of local strategies to protect communities from future heat events.

Many areas across the globe rely on upwind land areas for their precipitation supply through terrestrial precipitation recycling. Here we simulate global precipitation recycling in four climate and land-use scenarios until 2100. We find that global terrestrial moisture recycling decreases by 1.5 % with every degree of global warming but with strong regional differences.

A social tipping process is a large change in a social group that can be started by few people. Does the 80/20 rule apply here? We see if this is the case for human social groups. We find that, if the social conditions allow, change occurs when around 25 % of people engage. While tipping can happen between 10 % and 43 %, most cases tip by 40 %. However, tipping is not guaranteed: when people are resistant, trusted friend groups and context-appropriate messaging help the process along.

While the El Niño–Southern Oscillation, a climate mode, has a similar impact on CO₂ growth rates across Earth system models, there is significant uncertainty in the processes behind this relationship. We found a compensatory effect that masks differences in the sensitivity of carbon fluxes to climate anomalies and observed that the carbon fluxes contributing to global CO₂ anomalies originate from different regions and are caused by different drivers.

Explosive cyclones and atmospheric rivers are two main drivers of extreme weather in Europe. In this study, we investigate their joint changes in future climates over the North Atlantic. Our results show that both the concurrence of these events and the intensity of atmospheric rivers increase by the end of the century across different future scenarios. Furthermore, explosive cyclones associated with atmospheric rivers last longer and are deeper than those without atmospheric rivers.

The ocean is forced at the surface by a heat flux and a freshwater flux. This noise can influence long-term ocean variability and large-scale circulation. Here we study noise characteristics in reanalysis data for these fluxes. We try to capture the noise characteristics by using several noise models and compare these to state-of-the-art climate models. A pointwise noise model performs better than the climate models and can be used as forcing in ocean-only models.

Ocean heat content (OHC) is an essential climate variable and is highly correlated with thermosteric sea level rise (TSL). In this study, ocean-thermal-expansion-based artificial neural network models were developed and validated to estimate TSL and, subsequently, OHC at 17 depths from the surface to 700 m. These models can accurately predict TSL and OHC for the given input data on sea surface temperature and sea surface salinity from any source.

Flows in the ocean are driven either by atmospheric forces or by small-scale internal disturbances that are inherently chaotic. We use computer simulation results to show that these chaotic oceanic disturbances can attain spatial scales large enough to alter the motion of Earth's pole of rotation. Given their size and unpredictable nature, the chaotic signals are a source of uncertainty when interpreting observed year-to-year polar motion changes in terms of other processes in the Earth system.

Utilizing the urban microclimate model PALM-4U, we show that temperature anomalies of ± 5 K at a depth of 2 m in the soil can impact atmospheric potential air temperatures within idealized domains. The impact depends on the season, time of day, land cover, and lateral boundary conditions of the domain. The magnitude of change depends mostly on seasonality and the time of day, ranging from 0.1 to 0.4 K. Land cover influences the absolute temperature but has a smaller impact on the magnitude.

Policy makers use global hydrological models to develop water management strategies and policies. However, it would be better if these models provided information at higher resolution. We present a first-of-its-kind, truly global hyper-resolution model and show that hyper-resolution brings about better estimates of river discharge, and this is especially true for smaller catchments. Our results also suggest that future hyper-resolution models need to include more detailed land cover information.

Current trends in CO₂ emissions increase the probability of an overshoot scenario in which temperatures exceed the targets of the Paris Agreement and are brought back afterwards with a net-negative emission strategy. This work analyses how the climate after the overshoot would differ from the climate before, linking large scale non-reversibility mechanisms to changes in regional climates and identifying those regions more impacted by changes in temperature and precipitation extremes.

The adaptive emission reduction approach is applied with Earth system models to generate temperature stabilization simulations. These simulations provide compatible emission pathways and budgets for a given warming level, uncovering uncertainty ranges previously missing in the Coupled Model Intercomparison Project scenarios. These target-based emission-driven simulations offer a more coherent assessment across models for studying both the carbon cycle and its impacts under climate stabilization.