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As more countries make net zero greenhouse gas emissions pledges, it is crucial to understand the effects on global climate after achieving net zero emissions. The climate has been found to continue to evolve even after the abrupt cessation of CO2 emissions, with some models simulating a small warming and others simulating a small cooling. In this study, we analyze if the temperature and precipitation changes post abrupt cessation of CO2 emissions are significantly different compared to natural climate variations. We find that the temperature changes are outside of natural variability for most models, whilst the precipitation changes are mostly non‐significant. We also demonstrate that post‐net zero temperature changes have implications for the remaining carbon budget. The possibility of further global warming post‐net zero adds to the evidence supporting more rapid emissions reductions in the near‐term. Plain Language Summary: As more countries commit to achieving net‐zero greenhouse gas emissions, it is essential to understand the impact this will have on the global climate beyond this point. It has been found that even after CO2 emissions are abruptly halted, the climate continues to change, with various models predicting either a slight warming or cooling effect. In our study, we investigate whether the temperature and precipitation changes that occur after the sudden cessation of CO2 emissions are noteworthy when compared to natural climate variations. Our analysis reveals that the temperature changes, in the majority of models, surpass what can be attributed to natural variability. However, the precipitation changes are generally not significant. Additionally, we observe that the temperature changes post‐net zero have implications for the remaining carbon budget. Key Points: Global mean surface temperature changes after abrupt CO2 emissions cessation are significant compared to natural variability in most modelsGlobal mean precipitation changes after 50 yrs are only significant compared to natural variability in models that warmThe uncertain temperature changes post‐net zero have implications for the remaining carbon budget [ABSTRACT FROM AUTHOR]

Abstract: The Paris Agreement aims to keep global warming well below 2°C above preindustrial levels with a preferred ambitious 1.5°C target. Developing countries, especially small island nations, pressed for the 1.5°C target to be adopted, but who will suffer the largest changes in climate if we miss this target? Here we show that exceeding the 1.5°C global warming target would lead to the poorest experiencing the greatest local climate changes. Under these circumstances greater support for climate adaptation to prevent poverty growth would be required. [ABSTRACT FROM AUTHOR]

The article focuses on a study which examines the roles of both human-induced climate change and natural climate variability in the record wet winter southeast Australia. Information about the influence of the two factors on the circulation patterns conducive to unusually wet seasons as well as moisture availability is presented.

Record-breaking temperatures can detrimentally impact ecosystems, infrastructure, and human health. Previous studies show that climate change has influenced some observed extremes, which are expected to become more frequent under enhanced future warming. Understanding the magnitude, as a well as frequency, of such future extremes is critical for limiting detrimental impacts. We focus on temperature changes in Australian regions, including over a major coral reef-building area, and assess the potential magnitude of future extreme temperatures under Paris Agreement global warming targets (1.5°C and 2°C). Under these limits to global mean warming, we determine a set of projected high-magnitude unprecedented Australian temperature extremes. These include extremes unexpected based on observational temperatures, including current record-breaking events. For example, while the difference in global-average warming during the hottest Australian summer and the 2°C Paris target is 1.1°C, extremes of 2.4°C above the observed summer record are simulated. This example represents a more than doubling of the magnitude of extremes, compared with global mean change, and such temperatures are unexpected based on the observed record alone. Projected extremes do not necessarily scale linearly with mean global warming, and this effect demonstrates the significant potential benefits of limiting warming to 1.5°C, compared to 2°C or warmer. [ABSTRACT FROM AUTHOR]

The article focuses on defining new normal for extreme weather in climate change. A new normal has been applied to describe a diversity of weather and climate phenomena. Directing analysis of a new normal to extreme temperatures is motivated by several factors. Extreme weather and climate events occurring on subdaily to multiyear time scales and have significant socioeconomic costs and impacts on natural systems.

The article presents a study which investigates the role of El Niño and human-induced climate change to the increase in likelihood of heat and drought in Indonesia in July-October 2015. The study used the temperature and precipitation to assess the extreme event in the country. Results show that the dry season was attributed to El Niño and climate change.

During March 2021, large regions of Eastern Australia experienced prolonged heavy rainfall and extensive flooding. The maximum daily mean column integrated water vapor transport (IVT) over Sydney during this event was within the top 0.3% of all days since 1980, and the 10‐day mean IVT was in the top 0.2%. In this study, we have examined the change in frequency of extreme IVT events over Sydney in 16 climate models from the Coupled Model Intercomparison Project 6 under two Shared Socioeconomic Pathways (SSP245 and SSP585). Generalized Extreme Value modeling was used to further analyze the change in frequency of extreme IVT events. We found the probability of long duration high IVT events is projected to increase by 80% at the end of the century, but the future change in IVT is correlated to the rate of global and regional warming in each model. Plain Language Summary: During March 2021, large regions of Eastern Australia experienced prolonged heavy rainfall and extensive flooding. This was associated with strong horizontal water vapor transport over this region that persisted for approximately 10 days. The amount of water vapor transported over Sydney during this event was extreme and within the top 0.3% of all days since 1980. In this study, we used climate models to project how much more often events such as these may occur by the end of the twenty‐first century under two greenhouse gas emission scenarios. We found that the probability of long duration high water vapor transport over Sydney, as in March 2021, may increase by 80%. Key Points: Sydney's March 2021 floods were associated with persistent high water vapor transportThe probability of long‐duration high integrated water vapor transport events should increase by the end of the twenty‐first centuryDifferences in climate sensitivity within the CMIP6 ensemble may increase the spread of moisture flux projections [ABSTRACT FROM AUTHOR]

The Maritime Continent is a densely populated area of complex topography located between the Pacific and Indian Oceans. It is an area where model skill is particularly important but also difficult to obtain. In this study we examine interannual austral summer rainfall variability in the region and the teleconnection to the El Niño–Southern Oscillation (ENSO) in observation‐based data, reanalyses, and global and regional atmosphere‐only model simulations. We show that model ability to capture interannual rainfall variability is strongly related to model skill in reproducing the ENSO teleconnection to the region, despite strong spatial variability in the ENSO‐rainfall response in coastal areas. Model ability in capturing the spatial pattern of both the midtropospheric moisture and circulation response to ENSO is a strong predictor for model performance in capturing the ENSO‐Maritime Continent rainfall teleconnection. High‐resolution regional simulations and better performing models have opposing ENSO‐rainfall teleconnections between land and sea areas. Plain Language Summary: The Maritime Continent experiences substantial rainfall variability resulting in droughts and flooding. It is also a region of complex topography that is poorly resolved in global climate models. Here we analyze the year‐to‐year rainfall variability of the region in more detail. We find that models that perform well in capturing year‐to‐year variability have more realistic teleconnections to the El Niño–Southern Oscillation (ENSO). Models that have better represented ENSO‐rainfall relationships capture the observed spatial pattern of both the atmospheric moisture and circulation responses to ENSO. A high‐resolution model exhibits much more detailed representation of the atmospheric state with opposing ENSO‐rainfall relationships over land and sea that are not captured by the worst performing global models. The large range in model performance in the region should be considered when making climate projections for the Maritime Continent. Key Points: There is a large range in model skill in capturing interannual Maritime Continent rainfall variabilityMore skillful models capture El Niño–Southern Oscillation (ENSO) teleconnection to midlevel moisture and circulation over regionA high‐resolution regional model shows a different ENSO‐moisture teleconnection over land and sea that is missing from some global models [ABSTRACT FROM AUTHOR]

East-Central Asia is one of the most vulnerable and sensitive regions to climate change, and the variability of extreme precipitation attracts great attention due to the large population and the importance of its economy. Here, three special runs with the Community Earth System Model (CESM) are used to project the changes in representative extreme precipitation indices (Rx1day, Rx5day, R95p, SDII) over East-Central Asia under the 1.5 °C and 2 °C Paris Agreement limits. The results indicate that Rx1day and Rx5day will increase by 28% and 15%, respectively, under the 1.5 °C warming level relative to the historical period (1971–2000). Most areas over East-Central Asia are projected to experience an accelerated increase in response to a further 0.5 °C warming. Specifically, humid areas (HAs) are projected to experience a greater increase in R95p annual days and area fraction, whereas arid and semiarid areas (ASAs) may have threefold higher risks. The proportion of extreme precipitation in total will increase ~10% in most HAs in response to the 0.5 °C additional warming. Holding global warming at 1.5 °C instead of 2 °C reduces the occurrence of R95p annual days by ~3 days/year in humid areas and ~1 day/year in ASAs. For SDII, most HAs will experience 0.2–0.6 mm/day and 0.2–0.4 mm/day increases in 1.5 °C or 2 °C warming limits, especially in Southeast China and the Himalayas. Therefore, limiting global warming to under 1.5 °C is beneficial to reducing the occurrence and associated impact of precipitation extremes in East-Central Asia. [ABSTRACT FROM AUTHOR]

Abstract: In the last decade, climate mitigation policy has galvanized around staying below specified thresholds of global mean temperature, with an understanding that exceeding these thresholds may result in dangerous interference of the climate system. United Nations Framework Convention on Climate Change texts have developed thresholds in which the aim is to limit warming to well below 2 °C of warming above preindustrial levels, with an additional aspirational target of 1.5 °C. However, denoting a specific threshold of global mean temperatures as a target for avoiding damaging climate impacts implicitly obscures potentially significant regional variations in the magnitude of these projected impacts. This study introduces a simple framework to quantify the magnitude of this heterogeneity in changing climate hazards at 1.5 °C of warming, using case studies of emergent increases in temperature and rainfall extremes. For example, we find that up to double the amount of global warming (3.0 °C) is needed before people in high‐income countries experience the same relative changes in extreme heat that low‐income nations should anticipate after only 1.5 °C of warming. By mapping how much warming is needed in one location to match the impacts of a fixed temperature threshold in another location, this “temperature of equivalence” index is a flexible and easy‐to‐understand communication tool, with the potential to inform where targeted support for adaptation projects should be prioritized in a warming world. [ABSTRACT FROM AUTHOR]

The likelihood and severity of high‐impact future temperature extremes can be reduced through climate change mitigation efforts. However, meeting the Paris Agreement warming limits requires notably stronger greenhouse gas emissions reduction efforts by major emitters than existing pledges. We examine the impact of Paris‐era decision‐making by the world's three largest greenhouse gas emitters (EU, USA, and China) on projected future extreme temperature events. Country‐level contributions to the occurrence of future temperature extremes are calculated based on current emissions policies and sequential mitigation efforts, using a new metric called the Contribution to Excess Risk Ratio. We demonstrate the Contribution concept by applying it to extreme monthly temperature projections. In many regions, future extremes depend on the current and future carbon dioxide emissions reductions adopted by major emitters. By implementing stronger Paris‐era climate pledges, major emitters can reduce the frequency of future extremes and their own calculated contributions to these temperature extremes. Plain English Summary: Temperature extremes can damage aspects of human society, infrastructure, and our ecosystems. The frequency, severity, and duration of high temperatures are increasing in some regions and are projected to continue increasing with further global temperature increases as greenhouse gas emissions rise. While the international Paris Agreement aims to limit warming through emissions reduction pledges, none of the major emitters has made commitments that are aligned with limiting warming to 2 °C. In this analysis, we examine the impact of the world's three largest greenhouse gas emitters' (EU, USA, and China) current and future decisions about carbon dioxide emissions on the occurrence of future extreme temperatures. We show that future extremes depend on the emissions decisions made by the major emitters. By implementing stronger climate pledges, major emitters can reduce the frequency of future extremes and their own calculated contributions to these temperature extremes. Key Points: The contribution of major greenhouse gas emitters to future temperature extremes is calculatedProjected future extremes depend on current and near‐future CO2 emissions trajectories of the major emittersMajor emitters' calculated contributions to future temperature extremes is reduced through emissions mitigation [ABSTRACT FROM AUTHOR]