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Global mean surface warming has been slow over the past 15 years. An analysis of climate simulations suggests that the low warming rate can be explained by an unusual phase of El Niño/Southern Oscillation and solar and aerosol variability.

High evapotranspiration events are becoming more frequent because of anthropogenic climate change. This study shows robust increases in those events across many regions, indicating faster land drying and a growing risk of rapidly developing droughts.

In a net zero framework, Carbon Dioxide Removal with storage periods of less than 1000 years is insufficient to neutralize remaining fossil carbon dioxide emissions, suggest simulations with a reduced complexity climate model.

This study shows that historical precipitation variability shapes current and future record-breaking precipitation probabilities, with regions with low current records being more at risk. High-risk regions are abundant around the world, leading to a quarter billion people facing potential precipitation disasters by 2050.

Arctic warming has reduced cold-season temperature variability in the northern mid- to high-latitudes. Thus, the coldest autumn and winter days have warmed more than the warmest days, contrary to recent speculations.

Models and scenarios on which climate projection are based vary between IPCC reports. To facilitate meaningful comparison, this study provides probabilistic climate projections for different scenarios in a single consistent framework, incorporating the overall consensus understanding of the uncertainty in climate sensitivity, and constrained by the observed historical warming.

Flash droughts that are accompanied by extreme heat drive more severe and prolonged impacts on global ecosystems, according to analysis of global reanalysis data and satellite observations.

Most published geoengineering scenarios are climate modelling studies, which biases the public perception of what is possible and desirable. Scenarios should be used more broadly to engage scientists, policymakers and society in a debate about which future climate and world we want.

Emissions targets must be placed in the context of a cumulative carbon budget if we are to avoid dangerous climate change.

Updated models are being used for the new assessment report from the Intergovernmental Panel on Climate Change. This study compares projections from the latest models with those from earlier versions. The spread of results has not changed significantly, and some of the spread will always remain due to the internal variability of the climate system. As models improve, they are able to represent more processes in greater detail, allowing for greater confidence in their projections, in spite of model spread.

The formal detection of climate warming and its attribution to human influence has so far relied on the differences between natural and anthropogenic warming patterns. An alternative and entirely independent attribution method that relies on the principle of conservation of energy instead, confirms greenhouse gas warming by 0.85 °C since the mid-twentieth century, half of which was offset by aerosol cooling.

Independent statistical reconstructions of the global mean surface temperature from either ocean or land data show that existing estimates of early-twentieth-century ocean surface temperatures are too cold.

The adoption of the Paris Agreement is a historic milestone for the global response to the threat of climate change. Scientists are now being challenged to investigate a 1.5 °C world — which will require an accelerated effort from the geoscience community.

Quantifying the temperature impacts of anthropogenic emissions helps monitor proximity to the Paris Agreement goals. Human activities warmed global mean temperature during the past decade by 0.9 to 1.3 °C above 1850–1900 values, with 1.2 to 1.9 °C from greenhouse gases and −0.7 to −0.1 °C from aerosols.

Targets for reducing atmospheric carbon dioxide are related to regional changes in climate extremes rather than to changes in global mean temperature, in order to convey their urgency better to individual countries.

As climate models improve, decision-makers' expectations for accurate climate predictions are growing. Natural climate variability, however, limits climate predictability and hampers the ability to guide adaptation in many regions such as North America. Scientists, policymakers and the public need to improve communication and avoid raising expectations for accurate regional predictions everywhere.

The probability of record-shattering extreme precipitation events is projected to be higher in a changing than a stationary climate at the end of the century, with the steepest rise in vulnerability in the tropics, according to climate model simulations.

Many governments agreed to limit global mean temperature change to below 2 °C, yet this level has not been assessed scientifically. A synthesis of the literature suggests that temperature is the best available target quantity, but a safe level is uncertain.

The quest to determine climate sensitivity has been going on for decades, with disturbingly little progress in narrowing the large uncertainty range. But fascinating new insights have been gained that will provide useful information for policy makers, even though the upper limit of climate sensitivity will probably remain uncertain for the near future.

Reduced moisture supply during strong updraft events in summer by the late 21st century in northern mid- and high latitudes could shift the seasonal timing of extreme precipitation from summer into colder seasons such as spring and autumn, according to an analysis of future model projections

Political upsets could stall coordinated international mitigation action, but emissions and investments over the next few years will have long-term consequences. Any delays to mitigation or cuts to renewable energy research by the US will likely render the 2 °C target unachievable if a global precedent is set.

Climate sensitivity, the long-term warming due to doubled atmospheric CO₂ levels, is estimated in the range of 1.5 °C to 4.5 °C. A synthesis of work reveals that whether the value falls at the high or low end, future emissions will have to be strongly limited.

Including passive CO₂ uptake as an anthropogenic removal in greenhouse gas accounting systems could undermine the Paris Agreement; measures to address this include acknowledging the need for Geological Net Zero and disaggregated accounting for carbon sinks.

Uncertainties and subjective choices affecting remaining carbon budgets should be fully considered when applying them to international and national climate policies.

Detection and attribution typically aims to find long-term climate signals in internal, often short-term variability. Here, common methods are extended to high-frequency temperature and humidity data, detecting instantaneous, global-scale climate change since 1999 for any year and 2012 for any day.

The politically defined threshold of dangerous climate change is an increase of 2 degrees Celsius in the mean global temperature. Simulations here show that when carbon dioxide and a full suite of positive and negative radiative forcings are considered, total emissions from 2000 to 2050 of about 1,400 gigatonnes of carbon dioxide yield a 50% probability of exceeding this threshold by the end of the twenty-first century. 'Business as usual' emissions will probably meet or exceed this 50% probability.

Apparently contradictory conclusions regarding the ‘global warming hiatus’ are reconciled, strengthening the current scientific understanding that long-term global warming is extremely likely to be of anthropogenic origin.

Heatwaves are occurring with increasing frequency and intensity, necessitating prediction so as to minimize loss of life and other impacts. This Review outlines heatwave predictive capabilities at daily to decadal timescales, and discusses heatwave projections with anthropogenic warming.

Big data is increasingly popular in many research domains. This Perspective discusses where elements of big data approaches have been employed in climate research and where combining big data with theory-driven research can be most fruitful.

A long-term goal for climate policy can only be agreed through political processes, but science can inform these through mapping policy choices and the risks they create. Recommendations for the practical use of the IPCC's Fifth Assessment Report are provided.

Estimates of carbon budgets compatible with limiting warming to below specific temperature limits are reviewed, and reasons underlying their differences discussed along with their respective strengths and limitations.

There are discernible differences in climate impacts between 1.5 °C and 2 °C of warming. The extent of countries' near-term mitigation ambition will determine the success of the Paris Agreement's temperature goal.

Integrating uncertainties using insights from both observations and models narrows the range on the remaining carbon budget for 1.5 °C, as well as the transient climate response to cumulative CO₂ emissions.