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Reconstructions of ocean and land temperatures since ad 1500 indicate that sustained, industrial-era warming of land areas in the Northern Hemisphere and tropical oceans began earlier than previously thought, around the mid-nineteenth century.

The Antarctic Peninsula is one of the most rapidly warming regions on Earth. A reconstruction of ice melt from an ice core taken near the northeastern tip of the peninsula over the past 2,000 years shows that surface melt has accelerated during the twentieth century.

Abrupt climate changes in the glacial North Atlantic altered the position of wind systems in the Northern Hemisphere and tropics. Ice-core data show that this disruption also reached the southern westerlies.

During the most recent ice age, abrupt changes in the Arctic climate were transmitted through the ocean to Antarctica. An atmospheric link between the two hemispheres has now been identified across the Antarctic continent.

Coral records indicate that the variability of the Indian Ocean Dipole over the last millennium is strongly coupled to variability in the El Niño/Southern Oscillation and that recent extremes are unusual but not unprecedented.

El Niño–Southern Oscillation (ENSO) profoundly affects Australian weather, climate, ecosystems and socio-economic sectors. This Review presents the progress made in understanding ENSO teleconnections to Australian weather over the past 40 years, describing the atmospheric dynamics, complexities and impacts of this climate phenomenon.

Weather patterns associated with southeast Australia’s 2019/2020 Black Summer fire disaster were extremely rare occurrences over the past 2000 years, according to a fire-weather reconstruction using Antarctic ice-core records.

Abrupt changes are developing across Antarctica’s ice, ocean and biological systems; some of these changes are intensifying faster than equivalent Arctic changes, potentially irreversibly, and their interactions are expected to worsen other impacts across the Antarctic environment and global climate system.

Coral records from a range of sites extend the index of the Indian Ocean Dipole back to 1846. Indian Ocean Dipole events increased in strength and frequency in the twentieth century, coincident with the development of direct feedbacks with the Asian Monsoon.

An ice-core record from the northeastern Antarctic Peninsula shows that the present warming period in the region is unusual in the context of natural climate variability over the past two thousand years, and that continued warming could cause ice-shelf instability farther south along the peninsula.

The Southern Annular Mode (SAM) has shifted towards its positive phase owing to ozone depletion and increasing greenhouse gas concentrations. This Review discusses the dynamics, trends and projections of the SAM and how these will affect southern high-latitude climate, including Southern Ocean circulation, carbon cycling and the Antarctic cryosphere.

Climate variability in the Southern Hemisphere is dominanted by the Southern Annular Mode, which influences temperatures and latitudinal rainfall distribution. This work reconstructs its annual variability since the year 1000. The authors find that a positive trend since the 1940s is reproduced by climate model simulations with representative greenhouse gas forcings and ozone depletion. Early trends indicate a teleconnection to tropical Pacific climate, which may need to be considered in projections under climate change.

Antarctic ice-core records and atmospheric transport modelling used here show that the 13th-century rise of Māori culture in New Zealand led to a threefold increase of atmospheric black carbon.

Simulated annual wheat yields during 1889–2020 show that, since the 1990s, Indian Ocean Dipole has replaced El Niño Southern Oscillation as the dominant climate driver across most of the Australian wheatbelt. The occurrences of more positive Indian Ocean Dipole events in recent decades resulted in severe yield reductions.

The hottest boreal summer on record has driven widespread humid heat mortality across every continent of the Northern Hemisphere. With critical physiological limits to human heat tolerance drawing ever closer, this Comment highlights the urgent need to limit further climate warming and emphasizes the adaptation challenge ahead.

Compared to the past few centuries, Central Pacific El Niño events have become more frequent, whereas the number of Eastern Pacific events has declined in the most recent decades, according to reconstructions from a network of seasonally resolved coral records.

Global temperature fluctuations during the last 2,000 years caused consistent changes in ocean evaporation and atmospheric moisture condensation processes, reflected in coherent water isotope signals in a large compilation of proxy records.

Antarctic climate trends observed in the satellite record are compared with a two hundred year paleoclimate record. The satellite record is found to be too short to attribute changes to anthropogenic forcing, with natural variability overwhelming the forced signal.

The Indian Ocean has undergone substantial heat and freshwater changes. This Review uses various data sources to examine the causes of contemporary and longer-term hydrological changes, revealing that trends over the twentieth century are linked to anthropogenic forcing, but that those since 1980 are related to the Interdecadal Pacific oscillation.

 Analysis of the East Antarctic Ice Sheet response to past warm periods and current observations of change highlight the importance of satisfying the Paris Climate Agreement to avoid a multi-metre contribution to sea level over the next few centuries.

The Indian Ocean Dipole (IOD) exerts strong control on the Indo-Pacific climate. This Review outlines twenty-first-century changes in the IOD, noting robust increases in eastern pole sea surface temperature variability, more frequent strong and early positive IOD events, and less frequent moderate positive IOD events.

A review of Earth system changes associated with past warmer climates provides constraints on the environmental changes that could occur under warming of 2 °C or more over pre-industrial temperatures.

Multiple climate contributors to fire risk in southeast Australia have led to an increase in fire extent and intensity over the past decades that will likely continue into the future, suggests a synthesis of climate variability, long-term trends and palaeoclimatic evidence.

Regional drying in southwest Australia over the past six decades has resulted in a decrease in rainfallassociated recharge of aquifers which is unprecedented over the last 800 years, according to speleothem oxygen isotope data from four cave systems.

Karst hydrology exerts a key influence on oxygen isotopic compositions in cave speleothems, according to a global analysis of in-cave differences. The effect of flowpaths through fractures could affect speleothem-based reconstructions of past hydroclimates.

Australia experiences meteorological droughts due to insufficient moisture transport and heavy precipitation, which are influenced by climate variability and land processes, and are expected to become longer and more frequent, according to a review of observational and model-based studies.