Pre-industrial Levels Research Articles

Quantifying risks avoided by limiting global warming to 1.5 or 2 °C above pre-industrial levels

The Paris Agreement aims to constrain global warming to ‘well below 2 °C’ and to ‘pursue efforts’ to limit it to 1.5 °C above pre-industrial levels. We quantify global and regional risk-related metrics associated with these levels of warming that capture climate change–related changes in exposure to water scarcity and heat stress, vector-borne disease, coastal and fluvial flooding and projected impacts on agriculture and the economy, allowing for uncertainties in regional climate projection. Risk-related metrics associated with 2 °C warming, depending on sector, are reduced by 10–44% globally if warming is further reduced to 1.5 °C. Comparing with a baseline in which warming of 3.66 °C occurs by 2100, constraining warming to 1.5 °C reduces these risk indicators globally by 32–85%, and constraining warming to 2 °C reduces them by 26–74%. In percentage terms, avoided risk is highest for fluvial flooding, drought, and heat stress, but in absolute terms risk reduction is greatest for drought. Although water stress decreases in some regions, it is often accompanied by additional exposure to flooding. The magnitude of the percentage of damage avoided is similar to that calculated for avoided global economic risk associated with these same climate change scenarios. We also identify West Africa, India and North America as hotspots of climate change risk in the future.

Quantifying the Role of Seasonality in the Marine Carbon Cycle Feedback: An ESM2M Case Study

AbstractObservations and climate models indicate that changes in the seasonal amplitude of sea surface carbon dioxide partial pressure (A‐pCO2) are underway and driven primarily by anthropogenic carbon (Cant) accumulation in the ocean. This occurs because pCO2 is more responsive to seasonal changes in physics (including warming) and biology in an ocean that contains more Cant. A‐pCO2 changes have the potential to alter annual ocean carbon uptake and contribute to the overall marine carbon cycle feedback. Using the GFDL ESM2M Large Ensemble and a novel analysis framework, we quantify the influence of Cant accumulation on pCO2 seasonal cycles and sea‐air CO2 fluxes. Specifically, we reconstruct alternative evolutions of the contemporary ocean state in which the sensitivity of pCO2 to seasonal thermal and biophysical variation is fixed at preindustrial levels, however the background, mean‐state pCO2 fully responds to anthropogenic forcing. We find near‐global A‐pCO2 increases of >100% by 2100, under RCP8.5 forcing, with rising Cant accounting for ∼100% of thermal and ∼50% of nonthermal pCO2 component amplitude changes. The other ∼50% of nonthermal pCO2 component changes are attributed to modeled changes in ocean physics and biology caused by climate change. Cant‐induced A‐pCO2 changes cause an 8.1 ± 0.4% (ensemble mean ± 1σ) increase in ocean carbon uptake by 2100. This is because greater wintertime wind speeds enhance the impact of wintertime pCO2 changes, which work to increase the ocean carbon sink. Thus, the seasonal ocean carbon cycle feedback works in opposition to the larger, mean‐state feedback that reduces ocean carbon uptake by ∼60%.

Large Methane Emission Fluxes Observed From Tropical Wetlands in Zambia

AbstractMethane (CH4) is a potent greenhouse gas with a warming potential 84 times that of carbon dioxide (CO2) over a 20‐year period. Atmospheric CH4 concentrations have been rising since the nineteenth century but the cause of large increases post‐2007 is disputed. Tropical wetlands are thought to account for ∼20% of global CH4 emissions, but African tropical wetlands are understudied and their contribution is uncertain. In this work, we use the first airborne measurements of CH4 sampled over three wetland areas in Zambia to derive emission fluxes. Three independent approaches to flux quantification from airborne measurements were used: Airborne mass balance, airborne eddy‐covariance, and an atmospheric inversion. Measured emissions (ranging from 5 to 28 mg m−2 hr−1) were found to be an order of magnitude greater than those simulated by land surface models (ranging from 0.6 to 3.9 mg m−2 hr−1), suggesting much greater emissions from tropical wetlands than currently accounted for. The prevalence of such underestimated CH4 sources may necessitate additional reductions in anthropogenic greenhouse gas emissions to keep global warming below a threshold of 2°C above preindustrial levels.

Coastal Marine Geochemical Provinces and Background Values in Sediments: A Methodological Approach

The Italian approach to determining background values (BGVs) of metals and trace elements in marine sediments according to the national legislation transposing the water framework directive (WFD) has been illustrated. This study may be helpful for all countries that need to establish local BGVs for the correct assessment of contamination in areas with wide geological and geochemical variability and, particularly, for those that need assessing the good chemical status according to the WFD. The first step was clearly defining the BGV as a concentration value that allows for discriminating between natural and anthropogenic contributions and establishing the concept of the marine geochemical province (MGP). Successively, criteria for delimiting the MGPs were provided, similar to those adopted for the geochemical mapping of the territory. Finally, an integrated method based on the constitution of a dataset from unpolluted sediments obtained from pre-industrial levels was chosen for determining the BGV.

Awareness and Perceptions of University Students in the Business College towards Energy Savings and Renewable Energy Sources in Saudi Arabia

Achieving sustainable development goals and realizing the goal of Kyoto Protocol, Paris Agreement and Glasglow Climate Pact to keep the world temperature rise lower than 2o C above pre-industrial levels, there is a need to engage some of the stakeholders who are part of the energy users in a society. Majority of the Saudi citizens are youths and a large number of them are still undergoing university education. This study assessed the awareness, perception and attitudes of university students in the college of business towards energy savings and renewable energy (RE) in the Eastern province of Saudi Arabia. The results using descriptive analysis revealed that the level of awareness of students about energy savings and renewable energy is at medium level. While few of them are concerned about energy-savings and RE usage, many of them are indifferent, which could be as a result of their poor knowledge and awareness about it. At least 3 out of 5 students believed that fossil fuels have negative impact on the environment. Furthermore, the results of logistic regression indicate that there is no statistical difference between gender, age and awareness of energy savings and RE. More so, the results also show that energy education and family factors are statistically significant in influencing students’ awareness of energy savings and RE. Appropriate government policy in university academic curriculum which incorporates energy savings and renewable energy education is recommended in order to realize the government Vision 2030 which is also in line with the UN Climate goal.

Thailand’s mid-century greenhouse gas emission pathways to achieve the 2 degrees Celsius target

BackgroundThe Paris Agreement aims at minimizing threats of climate change by keeping global temperature rise well below 2 degrees Celsius above the pre-industrial level and to pursue efforts to limit the rise to 1.5 degrees Celsius. The Representative Concentration Pathways (RCPs) are developed to investigate GHG emission pathways. RCP2.6 focuses on limiting the global temperature rise to less than 2 degrees Celsius. This paper assesses the impacts of carbon price and CCS on energy and GHG emissions in Thailand. The no carbon price (T0) and the carbon price pathways are compared. In addition, the net-zero emissions and year are discussed.ResultsThe decarbonized energy system with low-carbon power generation and increased electricity usage in the final energy consumption is the main pillar of GHG mitigation. Imposing carbon prices; increasing solar, wind, and biomass electricity generation; energy efficiency improvements in power generation; and energy savings in the industry and the building sectors, will be the key options for clean power generation in the carbon prices (CT) scenarios. Renewable electricity, coal and natural gas, coupled with CCS and bio-energy with CCS (BECCS) will be utilized significantly to curb GHG emissions. The increase of renewable energy and the electrification of end-use plays a key role in reducing GHG emissions. Fuel switching from diesel to biodiesel, energy efficiency improvement and electric pick-ups and trucks will help reducing GHG emissions in the transport sector.ConclusionsThere are three major policy implications to meet Thailand’s 2 degrees Celsius target. First, carbon prices will be the mechanism to accelerate the transformation in the energy sector. Wind and solar electricity will be key pillars of clean electricity in 2050. Policy-makers should update the renewable electricity plans to meet Thailand’s 2 degrees Celsius target in 2050. Second, coal- and gas-fired plants, and BECCS will become important options in reducing CO2 emissions. The policy-makers should investigate the application of CCS in the power sector and the storage location. Third, a major transformation in the transport sector is critically needed. Liquid biofuel and electrification in pick-ups, sedans, and trucks will help reduce GHG emissions.

Optimization of the possible pathways for gradual energy system decarbonization

The European Union and other signatories to the Paris Climate Accord have agreed to limit global warming to 2° Celsius above pre-industrial levels. Previously published studies have examined the optimal energy system structure required to satisfy carbon neutrality end goals. This research focuses on addressing the intermediate steps towards decarbonization. The steps are quantified as the percentage share of renewable energy sources. The objective of the optimization is to reach a predetermined level of renewable energy and emissions, minimize curtailment of renewable energy sources, minimize system cost, and limit the use of natural resources such as biomass in the energy sector. Considered technologies in the optimization process are energy-generating capacities, demand response technologies, and energy storage. The results of such a method reflect the use of considered technologies and are displayed as a function of renewable energy share and carbon dioxide emissions level, which also represent the decarbonization timeline from 2020 to 2050. The method is carried out with the use of energy planning software EnergyPLAN and highly modified Python-based optimization software EPLANopt. The results presented in the research display the necessity for continuous implementation of variable generating capacities as well as demand response technologies, mainly vehicle to grid.

Impacts of Suppressing Excessive Light Rain on Aerosol Radiative Effects and Health Risks

AbstractGlobal climate models (GCMs) have been used widely to study radiative forcing and health risks of aerosols. A recent study using two GCMs found that light rain plays a dominant role in controlling aerosol loading. However, “too much light rain and too little heavy rain” is a longstanding bias in GCMs. It is unclear how much light rain affects aerosol‐cloud‐radiation interactions and health risks from air pollution. Here we show that, with the correction of the rainfall intensity spectrum in the National Center for Atmospheric Research Community Atmosphere Model version 5.3 by introducing a stochastic deep convection scheme, the reduced frequency of light rain (1–20 mm d−1) results in changes of aerosol direct radiative effects (DRE) of up to −0.5 ± 0.03 W/m2 and aerosol cloud radiative effects (CRE) of up to −0.9 ± 0.03 W/m2. The total (CRE + DRE) radiative effects of light rain‐mediated aerosol changes exceed the present‐day anthropogenic forcing of aerosols relative to preindustrial levels from the Coupled Model Intercomparison Project (CMIP5&6) models. However, the correction of the rainfall intensity spectrum has little effect on anthropogenic aerosol forcing (defined as the radiative perturbation due to changes in aerosol concentrations between the industrial era and preindustrial levels). Due to increased exposure to fine particulates (PM2.5), the estimated global total premature mortality is much higher than previously estimated, by 300,000 ± 60,000 deaths per year, and is more severe in populous regions such as India and China. The findings in this study highlight the need to understand uncertainties in radiative effects and health risks of aerosols due to simulation biases of precipitation in GCMs.

Temperature targets, deep uncertainty and extreme events in the design of optimal climate policy

We study optimal climate policy consistent with the constraint that average global temperature remains below 1.5 ∘ C relative to pre-industrial levels. We consider a holistic representation of uncertainty including traditional risk, deep uncertainty and stochastic arrivals of climate-related disasters. Using robust control methods, we derive optimal emission and carbon tax paths and calculate when temperature exceeds the target in the absence of the constraint. We show that policy under deep uncertainty requires strong action now relative to pure risk but the policy stringency is reversed later. Preliminary estimates suggest that the COVID-19 impact on attainment of the temperature target is negligible.

Climate change and its impact on biodiversity and human welfare

Climate change refers to the long-term changes in temperature and weather due to human activities. Increase in average global temperature and extreme and unpredictable weather are the most common manifestations of climate change. In recent years, it has acquired the importance of global emergency and affecting not only the wellbeing of humans but also the sustainability of other lifeforms. Enormous increase in the emission of greenhouse gases (CO2, methane and nitrous oxide) in recent decades largely due to burning of coal and fossil fuels, and deforestation are the main drivers of climate change. Marked increase in the frequency and intensity of natural disasters, rise in sea level, decrease in crop productivity and loss of biodiversity are the main consequences of climate change. Obvious mitigation measures include significant reduction in the emission of greenhouse gases and increase in the forest cover of the landmass. Conference of Parties (COP 21), held in Paris in 2015 adapted, as a legally binding treaty, to limit global warming to well below 2 °C, preferably to 1.5 °C by 2100, compared to pre-industrial levels. However, under the present emission scenario, the world is heading for a 3–4 °C warming by the end of the century. This was discussed further in COP 26 held in Glasgow in November 2021; many countries pledged to reach net zero carbon emission by 2050 and to end deforestation, essential requirements to keep 1.5 °C target. However, even with implementation of these pledges, the rise is expected to be around 2.4 °C. Additional measures are urgently needed to realize the goal of limiting temperature rise to 1.5 °C and to sustain biodiversity and human welfare.

Social cost of carbon under a carbon-neutral pathway

Climate change is the challenge of the century, and achieving the goals of the Paris Agreement will require worldwide cooperation and mutual effort. Over 120 countries have made their net-zero commitments, and quantifying the social cost of carbon (SCC), i.e. the climate damage caused by an additional ton of CO2 emissions, under a carbon-neutral pathway would provide a carbon price benchmark for policymakers. Here, we set in detail the emission trajectories of different jurisdictions under a carbon-neutral pathway based on the submitted nationally determined contributions. We then assess global and regional warming, climate change damages, and the SCC with the Policy Analysis of Greenhouse Effect integrated assessment model. We find a peak warming of about 2.1 °C relatives to pre-industrial levels in this century under our carbon-neutral emission pathway. And even if all countries meet their carbon-neutral commitments, this would not be sufficient to limit global warming to 1.5 °C relative to pre-industrial levels. We compare the SCC using fixed discount rates, dynamic discounting, and an equity weighting approach. Notably, the introduction of equity weights would increase the estimated SCC from 79 (11–186) to 291 (83–592) US$ per tCO2. Climate change damages will be borne primarily by warmer and poorer countries, and this profound inequality would likely undermine efforts to eradicate extreme poverty. Statistics on current carbon taxes and carbon trading prices show that they are notably lower than global or even regional SCCs, suggesting that the current system does not adequately reflect the global externalities of CO2 emissions. More studies are needed to assess the equity aspects of climate change impacts, to help refine mechanisms to align domestic interests with global interests, and to facilitate the implementation of national carbon-neutral commitments in place.

Evaluation and joint projection of temperature and precipitation extremes across Canada based on hierarchical Bayesian modelling and large ensembles of regional climate simulations

Individual and joint variations of extreme temperature and precipitation are assessed across Canada using the large ensemble of Canadian Regional Climate Model simulations (CanRCM4-LE) and two corresponding multivariate bias-corrected datasets (Canadian Large Ensembles Adjusted Datasets, CanLEAD-E & S). The overall performance of the three 50-member ensembles is evaluated against the NRCANmet gridded observation for 1951–2000. A hierarchical Bayesian framework is then applied to analyze the biases of each ensemble member, characterize the ensemble uncertainties associated with internal climate variability, and assess the trends and the joint distributions of temperature and precipitation. Further, projected changes of extreme climate indices are assessed across the three ensembles in the historical period and four future scenarios corresponding to +1.5 °C to +4.0 °C warming above the pre-industrial level of 1850–1900. Results show that the CanLEAD products have lower warm and wet biases compared to CanRCM4-LE over most regions and in all seasons except in winter. CanLEAD-S significantly reduces precipitation biases and represents the behaviour of extreme climate indices better than the other two ensembles. All ensembles consistently project strong warming and wetting trends over most parts of southern Canada excluding the Canadian Prairies in summer, which shows a drying trend towards the end of the 21st century. The ensembles show increases in hot extremes in central and southeastern Canada and increases in wet extremes in western coastal regions. The results of the study suggest that CanLEAD-E&S can be used as reliable products for climate change impact assessments at regional scales particularly for the analysis of nonstationary compound events.

Metal Sourcing For a Sustainable Future

Drastic measures are required to meet the standards of the Paris Agreement and limit the increase of global average temperatures well below 2°C compared to pre-industrial levels. Mining activities are typically considered as unsustainable but, at the same time, metals such as cobalt and lithium are essential to sustain the energy transition. Several sustainability goals defined by the United Nations (UN) require large quantities of raw materials. Exploration and extractives activities are required in order to contribute to meeting sustainability standards. Future sourcing of metals will need to implement procedures that go well beyond current ecological, economic, and social requirements and practices. In this paper we assess the usual sustainability criteria and how they apply to the extractives sector. Sustainability can only be achieved if one accepts that the natural capital can be substituted by other forms of capital (so called weak concept of sustainability). Sourcing the raw materials increasingly demanded by our societies will need transparent and inclusive stakeholder participation as well as a holistic understanding of the impact of extractives activities to reach this weak sustainability status. Our analysis shows that the sustainability of mining cannot be reached without harmonized political instruments and investment policies that take the three pillars of environmental, economic, and social sustainability as a major priority.

Efficacy of the global protected area network is threatened by disappearing climates and potential transboundary range shifts

Protected areas are essential to conserving biodiversity, yet changing climatic conditions challenge their efficacy. For example, novel and disappearing climates within the protected area network indicate that extant species may not have suitable climate in protected areas in the future. Further, potential transboundary range shifts, those that involve movement from one country to another, are also challenging because physical (e.g. fencing) and non-physical barriers (e.g. contrasting conservation policies) may impede climate-induced movements. Through the lens of climate analogs, we examined disappearing and novel climates within the global terrestrial protected area network and the potential for transboundary range shifts among protected areas under global warming 2 °C above preindustrial levels. We found that globally, climates in 24% of protected lands will no longer be protected within a 500 km radius of their focal location (indicating disappearing climates within the protected area network), while 36% of protected lands will gain climates not previously protected (indicating novel climates within the protected area network). Further, we found that potential transboundary range shifts are widespread but variable; for example, 23% of protected climates in Europe and >50% of protected climates in Africa under climate change are located in a different country than the focal protected areas. As the global conservation community actively deliberates conservation frameworks (e.g. 30% by 2030), our study offers insights to reduce the prevalence of novel and disappearing climates within the global protected area network via strategic conservation actions and underscores the importance of setting and accommodating targets and strategies that transcend national boundaries.

Monitoring of a Broad Set of Pharmaceuticals in Wastewaters by High-Resolution Mass Spectrometry and Evaluation of Heterogenous Catalytic Ozonation for Their Removal in a Pre-Industrial Level Unit

The removal of contaminants of emerging concern (CECs) occurring in wastewater effluents, such as pharmaceutically active substances (PhACs) and personal care products, pose a big research challenge since they can be a major source of pollution for water bodies and a danger to public health. The objective of this work was to perform a comprehensive monitoring of a broad set of PhACs (>130) in a wastewater treatment plant (WWTP) close to Thessaloniki (Greece), as well as to evaluate the potential of heterogeneous catalytic ozonation for the removal of CECs from wastewater through a continuous flow system. The high-resolution mass spectrometry analysis revealed the highest average concentrations for irbesartan (1817 ng/L). Antihypertensives along with antibiotics, psychiatrics, and β-blockers were found to aggravate the effluents. Removal efficiency after conventional treatment was >30%. The results from catalytic ozonation unit operation indicate that the introduction of a proper solid material that acts as catalyst can enhance the removal of CECs. A preliminary risk assessment using the risk quotient (RQ) revealed that irbesartan and telmisartan entail high acute risk. The overall results underline the urgent need to incessantly monitor PhACs and expand the toxicological studies to establish the sublethal and chronic effects on aquatic organisms.

Towards a Sustainable China-Africa Forest Products Trade; an Assessment of Environmental Implications for FOCAC Members

Forest products have become an integral component of China-Africa trade engagement. However, with increasingly global climate change warnings and the need to turn down the heat below the pre-industrial level, understanding the trade-off from forest trade in relation to CO2 emissions is paramount in shaping forest product trade sustainability in the long run. This study, therefore, tests the haven and halo hypothesis based on the FMOL technique by analyzing China-FOCAC forest products trade engagements. A balanced panel data of 20 FOCAC members were selected based on availability and consistency from 2000-2014. The variables; forest products trade (exports value), GDP per capita, FDI inflow, institutional quality, energy use and carbon emissions were gleaned from the world bank and the United Nations database. The descriptive statistics results reveal a disparity in economic growth, FDI inflow and value of forest products exports among FOCAC members. Per the FMOL estimation results, the China-FOCAC forest products trade has an insignificant impact on the level of carbon emissions in the selected countries which contributes to the ongoing debate on whether Africa is a pollution haven for China. Nevertheless, Per capita GDP and energy use are significant drivers of emissions whereas FDI’s and the quality of institutions have shown high potential for transforming the quality of the environment in the selected countries. These results are paramount in shaping existing and future forest trade agreements.

Negative Emissions as the New Frontier of Photoelectrochemical CO2 Reduction

AbstractThe remaining carbon budgets compatible with limiting global warming to 1.5 or 2 °C above preindustrial levels are shrinking rapidly. An already firmly anticipated, but highly controversial measure to mitigate this challenge is the large‐scale implementation of negative emissions, removing carbon dioxide from the atmosphere. Many of the currently considered negative emission technologies (NET) are based on natural photosynthesis, associated with large land footprints. Photoelectrochemical carbon sinks, on the other hand, promise to combine high conversion efficiencies with versatile storage options. Efficient sink products differ from the products typically considered for solar fuels, which will require novel catalysts and device designs. The development of efficient devices also has to take into account climatic parameters of the local environment as especially the ambient temperature affects device operation. While still in an early stage of development, carbon drawdown by such an artificial photosynthesis approach could be a valuable extension of the portfolio of NET.

Participatory approaches enhance a sense of urgency and collective efficacy about climate change: Qualitative evidence from the world climate simulation

Despite clear scientific evidence to support an urgent need to cut greenhouse gas emissions, societal action remains inadequate to meet international climate goals. New approaches in climate change communication are needed to motivate climate action. World Climate is an interactive, engaging, and socially rich role-play simulation that challenges participants to negotiate a climate agreement to limit warming to 2 °C above pre-industrial levels. During the simulation, participants use a computer model, C-ROADS, to test their greenhouse gas emissions decisions and get immediate feedback on the resulting expected climate outcomes. In 2019, several programs that assist high school and college students who come from disadvantaged backgrounds implemented the World Climate simulation. In total, 39 participants who displayed the largest gains in their sense of urgency about climate change, measured through pre- and post-simulation surveys, were invited to participate in a semi-structured interview regarding their experience. Twelve individuals from four different simulation sessions were interviewed, and their responses were transcribed and categorized into codes. Results from this study show that interviewees attributed gains in their climate change risk perception to the simulation and also experienced gains in collective efficacy as a result. We constructed a causal loop diagram to visualize relationships between aspects of the simulation and gains in climate change beliefs, attitudes, and behaviors based on interview data. Insights from this qualitative study show that group deliberation guided by interaction with a model are important components to increasing urgency and climate action for the subset of the population interviewed.

Assessment of 21st Century Changing Sea Surface Temperature, Rainfall, and Sea Surface Height Patterns in the Tropical Pacific Islands Using CMIP6 Greenhouse Warming Projections

AbstractTropical Pacific Islands face unknown rates of future warming due to increased greenhouse gas emissions, but almost certain changing climate stresses. Continued global warming is projected to cause further changes to the mean conditions and variability of sea surface temperature (SST), rainfall, and sea surface height (SSH). Previous climate model simulations showed that the equatorial Pacific is likely to have greater increased rainfall, compared to elsewhere in the tropics. There is less certainty about future rainfall changes away from the equator, including around many of the numerous tropical Pacific Islands. Here, we assess the Coupled Model Intercomparison Project‐phase 6 (CMIP6) as it relates to future changes of SST, rainfall, and SSH in the tropical Pacific. Focus is on the island regions of Hawaii, Guam, and American Samoa, as well as the Niño 3.4 region. We consider two development narratives of the 21st century by assessing the SSP2‐4.5 and SSP5‐8.5 experiments, and describe climate changes in the tropical Pacific relative to the recent historical conditions that are likely for either 1.5°C or 3°C of global mean surface temperature (GMST) warming above preindustrial levels. Consistent with prior‐generation climate models, we find that future rainfall increases the most where SST warming is greatest, and also an overall increase of interannual variability associated with the El Niño‐Southern Oscillation (ENSO) affecting rainfall and SSH. We describe changes in SST, rainfall, and SSH for particular warming amounts, and make comparisons with time‐based climate assessments during the 21st century, which are relevant results toward better understanding uncertainty and supporting adaptation efforts in the tropical Pacific Islands.

WMO Global Annual to Decadal Climate Update: A Prediction for 2021–25

Abstract As climate change accelerates, societies and climate-sensitive socioeconomic sectors cannot continue to rely on the past as a guide to possible future climate hazards. Operational decadal predictions offer the potential to inform current adaptation and increase resilience by filling the important gap between seasonal forecasts and climate projections. The World Meteorological Organization (WMO) has recognized this and in 2017 established the WMO Lead Centre for Annual to Decadal Climate Predictions (shortened to “Lead Centre” below), which annually provides a large multimodel ensemble of predictions covering the next 5 years. This international collaboration produces a prediction that is more skillful and useful than any single center can achieve. One of the main outputs of the Lead Centre is the Global Annual to Decadal Climate Update (GADCU), a consensus forecast based on these predictions. This update includes maps showing key variables, discussion on forecast skill, and predictions of climate indices such as the global mean near-surface temperature and Atlantic multidecadal variability. it also estimates the probability of the global mean temperature exceeding 1.5°C above preindustrial levels for at least 1 year in the next 5 years, which helps policy-makers understand how closely the world is approaching this goal of the Paris Agreement. This paper, written by the authors of the GADCU, introduces the GADCU, presents its key outputs, and briefly discusses its role in providing vital climate information for society now and in the future.