This paper provides key insight into the methodology of Working Group III of the IPCC Sixth Assessment Report on climate mitigation. The paper will be essential reading for anyone wishing to understand the assessment of climate outcomes of mitigation pathways in the context of the Paris Agreement.

In 2020, a new international law was imposed that placed strong restrictions on sulfur emissions from the international shipping industry. In addition to reducing air pollution, an anticipated side effect was reduction of the climate cooling effect that is often associated with "ship-tracks". Aerosol pollutant emissions from ships, when they rise into overlying clouds, lead to higher cloud droplet number concentrations, smaller cloud droplet sizes, and clouds that are more reflective to incoming sunlight, easily seen in satellite imagery as long bright lines downwind of ships. Past studies into whether the new law has led to darker clouds have been equivocal. For this study, the authors used sophisticated statistical techniques to compare cloud droplet size and reflectivity before and after the law was implemented focusing on a shipping corridor in the southeast Atlantic. They found strong evidence that droplet sizes have indeed increased, and that clouds have darkened with a significant local climate warming. Globally, the impact is much smaller, but may still represent an important consideration for assessments of the total summed effect of aerosols on climate.

The NHESS paper “A climate-conditioned catastrophe risk model for UK flooding” by Bates and colleagues presents and validates a new flood model for the UK that simulates pluvial, fluvial and coastal flood risks at a resolution of 20 to 25 metres. The authors then use their scheme to estimate the probability-loss distribution for UK flooding under various future climate and policy scenarios. Their paper provides the most detailed and realistic analysis to date of current and future flood risk in the UK. The key findings of their work are: (1) Previous UK flood losses based on government data and used in national climate change risk assessments are overestimated by a factor of about 3. (2) Official UK estimates lie well outside the paper's modelled loss distribution, which is plausibly centred on the observations. (3) The UK 1% annual probability flood losses were only about 6% greater in the average climate conditions of 2020 than for the period of historical river flow and rainfall observations (centred approximately on 1995). (4) Increases in risk can be kept to around ~8% if all COP26 2030 carbon emission reduction pledges and ‘net zero’ commitments are implemented in full. (5) Implementing only the COP26 pledges increases UK 1% annual probability flood losses by ~23% above recent historical values, and potentially ~37% if climate sensitivity turns out to be higher than currently thought.

Machine Learning is a rapidly expanding technique in the field of weather and climate modelling. This paper takes stock of the state of the field at the present time, and will be invaluable to participants across the field and beyond who wish to understand the impact of Machine Learning on the field, its limitations, and current scope.

This paper examines the warning deficits in conjunction with the major flooding event in Germany of summer 2021. The event caused many fatalities and enormous damage. The warning procedures proved to be insufficient, and after investigations it was decided to install a cell broadcast system in Germany, which is already in place today. The deeper investigations on the warning perceptions and the influencing factors is of major interest to readers beyond the scientific community.

Tornadoes are having impact on peoples live and are in a general interest.

The manuscript presents a reconstruction of global temperature spanning the Holocene, which extends the scope of previous exercises in palaeoclimate data assimilation. The resulting reconstruction presents new insights into changes in global temperature over this period. Most notably, it confirms the results of previous studies that have shown a global cooling trend over the past 6,000 years. It also shows that a cooling trend is found even after allowing for potential biases in the proxies. These results are likely to be of considerable interest to the broader geoscience community.

The rapid increase in global warming in 2023 has sparked fears that Earth has entered a new warm state. Possible explanations for a warming spike have included transient changes in radiative forcing or deficiencies in climate models. This study shows that the primary cause is a mode of natural climate variability – the El Niño/Southern Oscillation (ENSO). The authors show that, while the magnitude of global warming caused by ENSO was particularly large in 2023, it is not unprecedented in the historical record. The implication is that global warming is continuing at a steady average rate without dramatic acceleration.

Tipping points have potentially major detrimental impacts on natural and human systems. This study highlights how the rate of change in external conditions is arguably one of the key tipping mechanisms for both natural and human systems in the human-dominated anthropocene. This notion of rate-induced tipping -- namely an instability that occurs when external conditions vary faster than some critical rate -- will likely become an increasingly important topic of scientific research in the coming years.

This article describes the effect of the recent (January 2022) Hunga Tonga-Hunga Ha’apai volcanic eruption on the stratosphere. The eruption was highly energetic and as a result erupted material reached altitudes of around 30km. Such eruptions, with the 1991 Pinatubo eruption being a noteworthy example, often have a significant effect on tropospheric weather and climate, through the radiative effects of the volcanic aerosol, which may remain in the stratosphere for 2 or 3 years or more. In the 30 years since the Pinatubo eruption observations of the stratosphere, primarily from satellites, have improved enormously and in this Letter the authors provide a detailed description of the evolution of volcanic aerosol and of other chemical species injected by the eruption over a 6-month period following the eruption. The authors show that one important effect of the eruption was to inject a large quantity of water vapour into the stratosphere and suggest that the largest impact of the eruption on tropospheric weather and climate will be via the radiative effect of this water vapour, rather than of the injected aerosol. The initial detailed picture of the impact of the Hunga Tonga-Hunga Ha’apai eruption on the stratosphere provided in this Letter will stimulate further study of this remarkable natural event, which provides a rare opportunity to test our scientific understanding.

I agree with the handling editor and suggest considering it as a highlight paper.

This paper proposes a novel method for translating past observed extreme weather events into current or future climates. It illustrates this with the analysis of an extreme windstorm that occurred in 1903. The latter storm would likely be more damaging if it occurred today rather than 120 years ago.

Sea level rise represents one of the most compelling aspects of anthropogenic climate change. The potential social and economic impacts are enormous, with little that can be done to mitigate them. It is therefore of critical importance that we are able to correctly anticipate these impacts in advance. This study presents a new, open-source platform that integrates numerical modelling with socioeconomic and physical datasets, whilst also allowing for the uncertainty in climate change projections. This tool therefore allows for new and improved estimates of the global costs of future sea level rise and is likely to be of widespread interest.

I think the paper contains some important messages for the management of soil water that have widespread implications

The health of the amazon ecosystem is a key indicator of the health of our planet. Hence, the editor feels that this paper will attract the attention of a broad audience and the media.

Paleontological knowledge transfer can be fun! This extended review paper of comics and graphic novels on the subject of paleontology discusses the potential for communicating paleontological topics to the public and the influence of contemporary paleoart in this genre. Additionally, the motivation for and the creation process of the bilingual graphic novel "EUROPASAURUS - Life on Jurassic Islands" - intended as modern science communication - is described. An extensive survey among readers of this book allows conclusions as to what the public expects and appreciates in such a work.

The paper reveals previously-unexplored behaviours of the Earth system and illustrates how some impacts of climate change will continue to increase even after emissions become net zero. These results highlight the urgency of both achieving net zero emissions and of conducting long-term adaptation planning.

The study by Franz et al. provides exciting new insights into deep biosphere processes during the 'boring billion', indicating that fungi-like eukaryotic organisms developed before 1 Ga and that a deep continental biosphere was already present in the Early Mesoproterozoic/Late Paleoproterozoic.

This article offers a wide ranging review of current understanding of the role various tropical cirrus cloud types play in the redistribution of water within the atmosphere and how they affect the changing Earth's energy balance by reflecting sunlight and preventing the escape of thermal energy to outer space. Improved understanding of these dynamics has been identified as critical for predicting whether such clouds may amplify or slow future global climate change. A clear exposition is provided of the various methods used to study tropical cirrus cloud characteristics and processes, including remote sensing, in situ measurements, modeling and laboratory work. Key questions include identifying how small-scale microphysical processes affect larger cloud structure, and how cirrus altitude and extent responds to changing radiation and thermodynamic profiles. A call is made not only for improved representations of cloud processes at finer scales, but also for a more holistic approach using a hierarchy of model detail. Such efforts would enable new knowledge obtained from studying even the smallest scales to be more readily placed within a broader context applicable to climate studies.

Achieving both performance and portability in a whole dynamical core implemented in a high-productivity language such as Python is an eye-opening result which rebuts some widely held assumptions in the geoscientific modelling community. This is a paper which everyone who writes geoscientific models should read.

This paper clearly demonstrates the value of the rescue of historical meteorological data, as they help to come to a better assessment of the characteristics of events in the past. Using such data, the study is able to give evidence for physical processes of particular relevance for the intensity of an historical hazardous event. The approach makes an assessment of such events in the context of climate change and variability possible.

Summer 2022 was memorable and record-breaking in much of Europe - for example heatwaves in France. This paper discusses marine heatwaves in the Mediterranean and northeastern Atlantic Ocean and their importance for European climate. It investigates the causes of increased sea surface temperature during summer 2022 for the seas around France through assessing the different atmospheric fluxes determining the upper ocean heat budget. It highlights the need for continuous monitoring of the ocean surface in order to assess the impact of these marine heatwave events.

This manuscript provides a novel and comprehensive assessment of uncertainty associated with sea level rise. The model description is thorough and it is applied to a number of possible scenarios. The conclusions are important for framing future discussions on sea level rise.

The paper provides the general overview on the upcoming EarthCARE mission, which carries a unique suite of active and passive instruments for aerosol, cloud and radiation observations. It is thought to be the introductory paper for the AMT Special Issue "EarthCARE Level 2 algorithms and data products".