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Nobel Prize in Physics 2021

The 2021 Nobel Prize in Physics has been awarded to Syukuro Manabe, Klaus Hasselmann and Giorgio Parisi for their advances in complex physical systems. In recognition of this award, Nature Portfolio presents a collection of research, review and opinion articles that celebrates the direct contributions by the awardees and the discoveries they have inspired.

Syukuro Manabe and Klaus Hasselmann are awarded the Nobel Prize “for the physical modelling of Earth’s climate, quantifying variability and reliably predicting global warming”. Their contributions laid the foundation for advances in climate modelling and development, and detection and attribution methodologies.

Giorgio Parisi received the award “for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales”, with applications including glasses, random lasers and optimization problems.

Complexity in physical systems

Successful projection of the distribution of surface temperature change increases our confidence in climate models. Here we evaluate projections of global warming from almost 30 years ago using the observations made during the past half century.

Commentary | | Nature Climate Change

A classic paper in 1967 reported key advances in climate modelling that enabled a convincing quantification of the global-warming effects of carbon dioxide — laying foundations for the models that underpin climate research today.

News & Views | | Nature

Climate science celebrates three 40th anniversaries in 2019: the release of the Charney report, the publication of a key paper on anthropogenic signal detection, and the start of satellite temperature measurements. This confluence of scientific understanding and data led to the identification of human fingerprints in atmospheric temperature.

Comment | | Nature Climate Change

“I did not believe that it was possible to study the Brownian motion with such a precision.” From a letter from Albert Einstein to Jean Perrin (1909).

Concepts | | Nature

For a problem as complex as turbulence, combining universal concepts from statistical physics with ideas from fluid mechanics has proven indispensable. Three decades since this link was formed, it is still providing food for new thought.

Commentary | | Nature Physics

Climate modelling and development

A new generation of sophisticated Earth models is gearing up for its first major test. But added complexity may lead to greater uncertainty about the future climate, finds Olive Heffernan.

News Feature | | Nature

A scientific consensus that humans are influencing the climatewill be behind any agreements on greenhouse-gas reductions nextmonth. But how can climate research have an optimal influenceon climate policy in the future?

Commentary | | Nature

Multi-actor integrated assessment models based on well-being concepts beyond GDP could support policymakers by highlighting the interrelation of climate change mitigation and other important societal problems.

Commentary | | Nature Geoscience

Many different methods have been developed to forecast climate phenomena like the El Nino-Southern Oscillation (ENSO) which makes a fair comparison of their capabilities crucial. In this perspective, the authors discuss how choices in the evaluation method can lead to an overestimated perceived skill of ENSO forecasts.

Perspective | Open Access | | Nature Communications

Although the differential equations that describe the physical climate system are deterministic, there are reasons, both theoretical and practical, why computational representations of these equations should be stochastic. This Perspective surveys the benefits of stochastic modelling of weather and climate.

Perspective | | Nature Reviews Physics

Earth system models project likely future climates, however, evaluation of their output is challenging. This Perspective discusses new evaluation approaches, considering both simulations and observations, to ensure credible information for decision-making.

Perspective | | Nature Climate Change

In 1990 the First Assessment Report of the Intergovernmental Panel on Climate Change was produced. It contained a prediction of the global-mean-temperature trend for 1990–2030 which, halfway through that period, appears accurate. This is remarkable in hindsight, considering a number of important external forcings were not included. This study concludes the greenhouse-gas-induced warming is largely overwhelming the other forcings.

Letter | | Nature 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.

Letter | | Nature Climate Change

Detection and attribution of climate change

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.

Article | | Nature Climate Change

Climate models project an intensification of extreme precipitation under climate change, but this effect is difficult to detect in the observational record. Here, the authors show that a physically interpretable anthropogenic impact on extreme precipitation is detectable in global observational data sets.

Article | Open Access | | Nature Communications

This work investigates when the anthropogenic signal in regional sea-level rise will emerge from natural variability. Considering thermal expansion and changes in density and circulation, 50% of the global ocean will show an anthropogenic signal by the early-to-mid 2040s, whereas when all variables are considered, the anthropogenic signal will emerge in over 50% of the global ocean by 2020. This is substantially earlier than for surface air temperature and has little dependence on emissions scenarios.

Letter | | Nature Climate Change

The impact of external influences on European temperatures before 1900 has been thought to be negligible. An analysis of reconstructions of seasonal European land temperatures and simulations from three global climate models instead suggests that external forcing is responsible for a best guess of 75% of the observed winter warming since the late seventeenth century.

Letter | | Nature Geoscience

A significant effect of anthropogenic activities has already been detected in observed trends in temperature and mean precipitation. But to date, no study has formally identified such a human fingerprint on extreme precipitation — an increase in which is one of the central theoretical expectations for a warming climate. Seung-Ki Min and colleagues compare observations and simulations of rainfall between 1951 and 1999 in North America, Europe and northern Asia. They find a statistically significant effect of increased greenhouse gases on observed increases in extreme precipitation events over much of the Northern Hemisphere land area.

Letter | | Nature

The relative importance of regional and global changes in atmospheric greenhouse gas and aerosol concentrations for regional changes in climate is not well known. A climate model analysis of tropical, mid-latitude and polar regions shows that the extratropics and, in particular, the Arctic region are sensitive to local changes in radiative forcing.

Article | | Nature Geoscience

Glassy physics and applications

Potential energy landscape models are often used to describe transitions in the glassy state. Here, the authors report that the landscape is much rougher than usually assumed, and demonstrate that it undergoes a transition to fractal basins before the jamming point is reached.

Article | | Nature Communications

Artificial neural networks now allow the dynamics of supercooled liquids to be predicted from their structure alone in an unprecedented way, thus providing a powerful new tool to study the physics of the glass transition.

News & Views | | Nature Physics

The response of amorphous solids to external stress is not very well understood. A study now shows that certain glasses, upon decreasing temperature, undergo a phase transition characterized by diverging nonlinear elastic moduli.

Letter | | Nature Physics

While temperature chaos is an equilibrium notion that denotes the extreme fragility of the glassy phase with respect to temperature changes, it remains unclear whether it is present in non-equilibrium dynamics. Here the authors use the Janus II supercomputer to prove the existence of dynamic temperature chaos, a nonequilibrium phenomenon that closely mimics equilibrium temperature chaos.

Article | Open Access | | Communications Physics

Replica symmetry breaking, in which identical systems subject to identical conditions evolve to different end states, has been predicted to occur in many contexts but has yet to be observed experimentally. Ghofraniha et al.report evidence for its occurrence in the pulse-to-pulse variations of a random laser.

Article | | Nature Communications

The K-satisfability problem is a combinatorial discrete optimization problem, which for K=3 is NP-complete, and whose random formulation is of interest for understanding computational complexity. Here, the authors introduce the backtracking survey propagation algorithm for studying it for K=3 and K=4.

Article | Open Access | | Nature Communications

Quantum annealing is expected to solve certain optimization problems more efficiently, but there are still open questions regarding the functioning of devices such as D-Wave One. A numerical and experimental investigation of its performance shows evidence for quantum annealing with 108 qubits.

Article | | Nature Physics

Disorder and geometric frustration usually lead to magnetic spins that point in random directions, as in a spin glass. So how can spin-glass behaviour emerge in a well-ordered system without static frustration? The presence of ‘dynamic frustration’ may explain the situation.

Letter | | Nature Physics