rlacombe/ClimateX huggingface dataset:
Understanding about past and future changes in weather and climate extremes has increased due to better observation-based datasets, physical understanding of processes, an increasing proportion of scientific literature combining different lines of evidence, and improved accessibility to different types of climate models (IPCC AR6_WGI, confidence: high)
In SSP1-2.6 and SSP2-4.5, changes in ERF also explain about half of the changes in the range of warming (IPCC AR6_WGI, confidence: medium)
For SSP5-8.5, higher climate sensitivity is the primary reason behind the upper end of the CMIP6- projected warming being higher than for RCP8.5 in CMIP5 (IPCC AR6_WGI, confidence: medium)
The differences in the few ESMs for which both emissions and concentration-driven runs were available for the same scenario are small and do not affect the assessment of global surface temperature projections discussed in Cross-Section Box TS.1 and Section TS.2 (IPCC AR6_WGI, confidence: high)
Multiple lines of evidence can be used to construct climate information on a global to regional scale and can be further distilled in a co-production process to meet user needs (IPCC AR6_WGI, confidence: high)
Many global and regional climatic impact-drivers have a direct relation to global warming levels (IPCC AR6_WGI, confidence: high)
Climate change has already altered CID profiles and resulted in shifting magnitude, frequency, duration, seasonality and spatial extent of associated indices (IPCC AR6_WGI, confidence: high)
These include heat, cold, wet and dry hazards, both mean and extremes; cryospheric hazards (snow cover, ice extent, permafrost) and oceanic hazards (marine heatwaves) (IPCC AR6_WGI, confidence: high)
Changes in GMST and GSAT over time differ by at most 10% in either direction (IPCC AR6_WGI, confidence: high)
Temperatures as high as during the most recent decade (2011–2020) exceed the warmest centennial-scale range reconstructed for the present interglacial, around 6500 years ago [0.2°C to 1°C] (IPCC AR6_WGI, confidence: medium)
The next most recent warm period was about 125,000 years ago during the last interglacial when the multi-centennial temperature range [0.5°C to 1.5°C] encompasses the 2011–2020 values (IPCC AR6_WGI, confidence: medium)
Global surface temperature in any individual year could exceed 1.5°C relative to 1850–1900 by 2030 with a likelihood between 40% and 60% across the scenarios considered here (IPCC AR6_WGI, confidence: medium)
Periods of reduced and increased global surface temperature trends at decadal time scales will continue to occur in the 21st century (IPCC AR6_WGI, confidence: very high)
It is likely that there was a net anthropogenic forcing of 0.0–0.3 Wm–2 in 1850–1900 relative to 1750 (IPCC AR6_WGI, confidence: medium)
Beginning approximately 6500 years ago, global surface temperature generally decreased, culminating in the coldest multi-century interval of the post-glacial period (since roughly 7000 years ago), which occurred between around 1450 and 1850 (IPCC AR6_WGI, confidence: high)
Over the last 50 years, global surface temperature has increased at an observed rate unprecedented in at least the last two thousand years (IPCC AR6_WGI, confidence: high)
The next most recent warm period was about 125,000 years ago during the Last Interglacial when the multi-centennial temperature range [0.5°C to 1.5°C] encompasses the 2011–2020 values (IPCC AR6_WGI, confidence: medium)
During the mid-Pliocene Warm Period, around 3.3–3.0 million years ago, global surface temperature was 2.5°C to 4°C warmer (IPCC AR6_WGI, confidence: medium)
Furthermore, the heating of the climate system continued during this period, as reflected in the continued warming of the global ocean (very high confidence) and in the continued rise of hot extremes over land (IPCC AR6_WGI, confidence: medium)
Since 2012, global surface temperature has risen strongly, with the past five years (2016–2020) being the hottest five-year period between 1850 and 2020 (IPCC AR6_WGI, confidence: high)
Vertical bars are 5–95th percentile ranges of estimated global surface temperature for the Last Interglacial and mid-Holocene (IPCC AR6_WGI, confidence: medium)
The other half arises because for central estimates of climate sensitivity, most scenarios show stronger warming over the near term than was estimated as ‘current’ in SR1.5 (IPCC AR6_WGI, confidence: medium)
If climate sensitivity lies near the lower end of the assessed very likely range, crossing the 1.5°C warming level is avoided in scenarios SSP1-1.9 and SSP1-2.6 (IPCC AR6_WGI, confidence: medium)
Global surface temperature in any individual year, in contrast to the 20-year average, could by 2030 exceed 1.5°C relative to 1850–1900 with a likelihood between 40% and 60%, across the scenarios considered here (IPCC AR6_WGI, confidence: medium)
The uncertainty ranges for the period 2081–2100 continue to be dominated by the uncertainty in equilibrium climate sensitivity and transient climate response (IPCC AR6_WGI, confidence: very high)
Continued GHG emissions greatly increase the likelihood of potentially irreversible changes in the global climate system (Box TS.9), in particular with respect to the contribution of ice sheets to global sea level change (IPCC AR6_WGI, confidence: high)
Global mean concentrations of anthropogenic aerosols peaked in the late 20th century and have slowly declined since in northern mid-latitudes, although they continue to increase in South Asia and East Africa (IPCC AR6_WGI, confidence: high)
The total anthropogenic effective radiative forcing (ERF) in 2019, relative to 1750, was 2.72 [1.96 to 3.48] W m–2 (IPCC AR6_WGI, confidence: medium)
The average magnitude and variability of volcanic aerosols since 1900 has not been unusual compared to at least the past 2500 years (IPCC AR6_WGI, confidence: medium)
The centennial rate of change of CO 2 since 1850 has no precedent in at least the past 800,000 years (Figure TS.9), and the fastest rates of change over the last 56 million years were at least a factor of four lower (IPCC AR6_WGI, confidence: low)
The increase since 1750 of 1137 ± 10 ppb (157.8%) far exceeds the range over multiple glacial–interglacial transitions of the past 800,000 years (IPCC AR6_WGI, confidence: high)
N 2O concentration trends since 1980 are largely driven by a 30% increase in emissions from the expansion and intensification of global agriculture (IPCC AR6_WGI, confidence: high)
Abundances of HFCs, which are replacements for CFCs and HCFCs, are increasing (IPCC AR6_WGI, confidence: high)
Ice cores show increases in aerosols across the Northern Hemisphere mid-latitudes since 1700 and reductions since the late 20th century (IPCC AR6_WGI, confidence: high)
Aerosol optical depth (AOD), derived from satellite- and ground-based radiometers, has decreased since 2000 over the mid-latitude continents of both hemispheres, but increased over South Asia and East Africa (IPCC AR6_WGI, confidence: high)
Global carbonaceous aerosol budgets and trends remain poorly characterized due to limited observations, but black carbon (BC), a warming aerosol component, is declining in several regions of the Northern Hemisphere (IPCC AR6_WGI, confidence: low)
Total aerosol ERF in 2019, relative to 1750, is −1.1 [−1.7 to −0.4] W m−2 (IPCC AR6_WGI, confidence: medium)
Since the mid-20th century, tropospheric ozone surface concentrations have increased by 30–70% across the Northern Hemisphere (IPCC AR6_WGI, confidence: medium)
Future changes in surface ozone concentrations will be primarily driven by changes in precursor emissions rather than climate change (IPCC AR6_WGI, confidence: high)
Stratospheric ozone has declined between 60°S–60°N by 2.2% from 1964–1980 to 2014–2017 (IPCC AR6_WGI, confidence: high)
Model estimates suggest no significant change in oxidizing capacity from 1850 to 1980 (IPCC AR6_WGI, confidence: low)
The proportion of tropical cyclones that are intense is expected to increase (high confidence), but the total global number of tropical cyclones is expected to decrease or remain unchanged (IPCC AR6_WGI, confidence: medium)
In the tropics, since at least 2001 (when new techniques permit more robust quantification), the upper troposphere has warmed faster than the near-surface (IPCC AR6_WGI, confidence: medium)
This has been accompanied by a strengthening of the Hadley Circulation in the Northern Hemisphere (IPCC AR6_WGI, confidence: medium)
It is likely that human influence has contributed to the poleward expansion of the zonal mean Hadley cell in the Southern Hemisphere since the 1980s, which is projected to further expand with global warming (IPCC AR6_WGI, confidence: high)
The frequency of intense extratropical cyclones is projected to decrease (IPCC AR6_WGI, confidence: medium)
Projected changes in the intensity depend on the resolution of climate models (IPCC AR6_WGI, confidence: medium)
With increasing global warming, some very rare extremes and some compound events (multivariate or concurrent extremes) with low likelihood in past and current climate will become more frequent, and there is a higher chance that events unprecedented in the observational record occur (IPCC AR6_WGI, confidence: high)
Continued Amazon deforestation, combined with a warming climate, raises the probability that this ecosystem will cross a tipping point into a dry state during the 21st century (IPCC AR6_WGI, confidence: low)
Compound events and concurrent extremes contribute to increasing probability of low-likelihood, high-impact outcomes and will become more frequent with increasing global warming (IPCC AR6_WGI, confidence: high)
Over the past four to six decades, it is virtually certain that the global ocean has warmed, with human influence extremely likely the main driver since the 1970s, making climate change irreversible over centuries to millennia (IPCC AR6_WGI, confidence: medium)
A long-term increase in surface open ocean pH occurred over the past 50 million years, and surface ocean pH as low as recent times is uncommon in the last 2 million years (IPCC AR6_WGI, confidence: medium)
Stratification (virtually certain), acidification (virtually certain), deoxygenation (high confidence) and marine heatwave frequency (IPCC AR6_WGI, confidence: high)
The ocean is currently warming faster than at any other time since at least the last deglacial transition (medium confidence), with warming extending to depths well below 2000 m (IPCC AR6_WGI, confidence: very high)
Ocean warming is irreversible over centuries to millennia, but the magnitude of warming is scenario-dependent from about the mid-21st century (IPCC AR6_WGI, confidence: medium)
The warming will not be globally uniform, with heat primarily stored in Southern Ocean water-masses and weaker warming in the subpolar North Atlantic (IPCC AR6_WGI, confidence: high)
Marine heatwaves have become more frequent over the 20th century (high confidence), approximately doubling in frequency (high confidence) and becoming more intense and longer since the 1980s (IPCC AR6_WGI, confidence: medium)
It is extremely likely that human influence has contributed to this salinity change and that the large-scale pattern will grow in amplitude over the 21st century (IPCC AR6_WGI, confidence: medium)
Direct observational records since the mid-2000s are too short to determine the relative contributions of internal variability, natural forcing and anthropogenic forcing to AMOC change (IPCC AR6_WGI, confidence: high)
Western boundary currents and subtropical gyres have shifted poleward since 1993 (IPCC AR6_WGI, confidence: medium)
Subtropical gyres, the East Australian Current Extension, the Agulhas Current, and the Brazil Current are projected to intensify in the 21st century in response to changes in wind stress, while the Gulf Stream and the Indonesian Throughflow are projected to weaken (IPCC AR6_WGI, confidence: medium)
All of the four main eastern boundary upwelling systems are projected to weaken at low latitudes and intensify at high latitudes in the 21st century (IPCC AR6_WGI, confidence: high)
Ocean acidification and associated reductions in the saturation state of calcium carbonate – a constituent of skeletons or shells of a variety of marine organisms – is expected to increase in the 21st century under all emissions scenarios (IPCC AR6_WGI, confidence: high)
A long-term increase in surface open ocean pH occurred over the past 50 million years (high confidence), and surface ocean pH as low as recent times is uncommon in the last 2 million years (IPCC AR6_WGI, confidence: medium)
Over the past 2–3 decades, a pH decline in the ocean interior has been observed in all ocean basins (IPCC AR6_WGI, confidence: high)
Deoxygenation is projected to continue to increase with ocean warming (IPCC AR6_WGI, confidence: high)
The range of a smaller subset of organisms has shifted equatorward and to shallower depths (IPCC AR6_WGI, confidence: high)
Phenological metrics associated with the life cycles of many organisms have also changed over the last two decades or longer (IPCC AR6_WGI, confidence: high)
The Arctic Ocean is projected to become practically sea ice-free in late summer under high CO 2 emissions scenarios by the end of the 21st century (IPCC AR6_WGI, confidence: high)
Glaciers will continue to lose mass at least for several decades even if global temperature is stabilized (IPCC AR6_WGI, confidence: very high)
Since the late 1970s, Arctic sea ice area and thickness have decreased in both summer and winter, with sea ice becoming younger, thinner and more dynamic (IPCC AR6_WGI, confidence: very high)
It is very likely that anthropogenic forcing, mainly due to greenhouse gas increases, was the main driver of this loss, although new evidence suggests that anthropogenic aerosol forcing has offset part of the greenhouse gas-induced losses since the 1950s (IPCC AR6_WGI, confidence: medium)
This practically sea ice-free state will become the norm for late summer by the end of the 21st century in high CO 2 emissions scenarios (IPCC AR6_WGI, confidence: high)
Arctic summer sea ice varies approximately linearly with global surface temperature, implying that there is no tipping point and observed/ projected losses are potentially reversible (IPCC AR6_WGI, confidence: high)
For each additional 1°C of warming (up to 4°C above the 1850–1900 level), the global volume of perennially frozen ground to 3 m below the surface is projected to decrease by about 25% relative to the present volume (IPCC AR6_WGI, confidence: medium)
However, these decreases may be underestimated due to an incomplete representation of relevant physical processes in ESMs (IPCC AR6_WGI, confidence: low)
Under RCP2.6 and RCP8.5, respectively, glaciers are projected to lose 18% ± 13% and 36% ± 20% of their current mass over the 21st century (IPCC AR6_WGI, confidence: medium)
It is virtually certain that the Greenland Ice Sheet has lost mass since the 1990s, with human influence a contributing factor (IPCC AR6_WGI, confidence: medium)
Projections of future Greenland ice-mass loss (Box TS.4, Table 1; Figure TS.11e) are dominated by increased surface melt under all emissions scenarios (IPCC AR6_WGI, confidence: high)
The total Antarctic ice mass losses were dominated by the West Antarctic Ice Sheet, with combined West Antarctic and Peninsula annual loss rates increasing since about 2000 (IPCC AR6_WGI, confidence: very high)
Mass losses from West Antarctic outlet glaciers, mainly induced by ice shelf basal melt (high confidence), outpace mass gain from increased snow accumulation on the continent (IPCC AR6_WGI, confidence: very high)
Human activities were very likely the main driver of observed GMSL rise since 1971, and new observational evidence leads to an assessed sea level rise over the period 1901 to 2018 that is consistent with the sum of individual components contributing to sea level rise, including expansion due to ocean warming and melting of glaciers and ice sheets (IPCC AR6_WGI, confidence: high)
Sea level responds to greenhouse gas (GHG) emissions more slowly than global surface temperature, leading to weaker scenario dependence over the 21st century than for global surface temperature (IPCC AR6_WGI, confidence: high)
This slow response also leads to long-term committed sea level rise, associated with ongoing ocean heat uptake and the slow adjustment of the ice sheets, that will continue over the centuries and millennia following cessation of emissions (IPCC AR6_WGI, confidence: high)
By 2100, GMSL is projected to rise by 0.28– 0.55 m (likely range) under SSP1-1.9 and 0.63–1.01 m (likely range) under SSP5-8.5 relative to the 1995–2014 average (IPCC AR6_WGI, confidence: medium)
New analyses and paleo-evidence since AR5 show this rate is very likely faster than during any century over at least the last three millennia (IPCC AR6_WGI, confidence: high)
Since AR5, there is strengthened evidence for an increase in the rate of GMSL rise since the mid-20th century, with an average rate of 2.3 [1.6–3.1] mm yr–1 over the period 1971–2018 increasing to 3.7 [3.2–4.2] mm yr–1 for the period 2006–2018 (IPCC AR6_WGI, confidence: high)
By 2300, GMSL will rise 0.3–3.1 m under low CO 2 emissions (SSP1-2.6) (IPCC AR6_WGI, confidence: low)
Under high CO 2 emissions (SSP5-8.5), projected GMSL rise is between 1.7 and 6.8 m by 2300 in the absence of MICI and by up to 16 m considering MICI (IPCC AR6_WGI, confidence: low)
However, over the 21st century, the majority of coastal locations have a median projected regional sea level rise within ±20% of the projected GMSL change (IPCC AR6_WGI, confidence: medium)
Projections show that while land and ocean sinks absorb more CO 2 under high emissions scenarios than low emissions scenarios, the fraction of emissions removed from the atmosphere by natural sinks decreases with higher concentrations (IPCC AR6_WGI, confidence: high)
The combustion of fossil fuels and land-use change for the period 1750–2019 resulted in the release of 700 ± 75 PgC (likely range, 1 PgC = 1015 g of carbon) to the atmosphere, of which about 41% ± 11% remains in the atmosphere today (IPCC AR6_WGI, confidence: high)
During the last decade (2010–2019), average annual anthropogenic CO 2 emissions reached the highest levels in human history at 10.9 ± 0.9 PgC yr–1 (IPCC AR6_WGI, confidence: high)
Of these emissions, 46% accumulated in the atmosphere (5.1 ± 0.02 PgC yr–1), 23% (2.5 ± 0.6 PgC yr–1) was taken up by the ocean and 31% (3.4 ± 0.9 PgC yr–1) was removed by terrestrial ecosystems (IPCC AR6_WGI, confidence: high)
This coherence between emissions and the growth in ocean and land sinks has resulted in the airborne fraction of anthropogenic CO 2 remaining at 44 ± 10% over the past 60 years (IPCC AR6_WGI, confidence: high)
Interannual and decadal variability of the ocean and land sinks indicate that they are sensitive to changes in the growth rate of emissions as well as climate variability and are therefore also sensitive to climate change (IPCC AR6_WGI, confidence: high)
Since the 1980s, carbon fertilization from rising atmospheric CO 2 has increased the strength of the net land CO 2 sink (IPCC AR6_WGI, confidence: medium)
Carbon dioxide emissions-driven simulations account for uncertainty in these feedbacks, but do not significantly change the projected global surface temperature changes (IPCC AR6_WGI, confidence: high)
Although land and ocean sinks absorb more CO 2 under high emissions than low emissions scenarios, the fraction of emissions removed from the atmosphere decreases (IPCC AR6_WGI, confidence: high)
This means that the more CO 2 that is emitted, the less efficient the ocean and land sinks become (IPCC AR6_WGI, confidence: high)
Under SSP3-7.0 and SSP5-8.5, the initial growth of both sinks in response to increasing atmospheric concentrations of CO 2 is subsequently limited by emerging carbon–climate feedbacks (IPCC AR6_WGI, confidence: high)
Under SSP1-1.9, models project that combined land and ocean sinks will turn into a weak source by 2100 (IPCC AR6_WGI, confidence: medium)
The frequency and intensity of heavy precipitation events have increased over a majority of those land regions with good observational coverage (IPCC AR6_WGI, confidence: high)
Over the past half century, key aspects of the biosphere have changed in ways that are consistent with large- scale warming: climate zones have shifted poleward, and the growing season length in the Northern Hemisphere extratropics has increased (IPCC AR6_WGI, confidence: high)
The amplitude of the seasonal cycle of atmospheric CO 2 poleward of 45°N has increased since the 1960s (very high confidence), with increasing productivity of the land biosphere due to the increasing atmospheric CO 2 concentration as the main driver (IPCC AR6_WGI, confidence: medium)
Global-scale vegetation greenness has increased since the 1980s (IPCC AR6_WGI, confidence: high)
Warming of the land surface during the period 1971–2018 contributed about 5% of the increase in the global energy inventory (Section TS.3.1), nearly twice the estimate in AR5 (IPCC AR6_WGI, confidence: high)
The warming pattern will likely vary seasonally, with northern high latitudes warming more during winter than summer (IPCC AR6_WGI, confidence: medium)
Human-induced climate change has contributed to increases in agricultural and ecological droughts in some regions due to increases in evapotranspiration (IPCC AR6_WGI, confidence: medium)
Earlier onset of snowmelt has contributed to seasonally dependent changes in streamflow (IPCC AR6_WGI, confidence: high)
The projected increase in heavy precipitation extremes translates to an increase in the frequency and magnitude of pluvial floods (IPCC AR6_WGI, confidence: high)
Concurrent heatwaves and droughts have become more frequent over the last century, and this trend will continue with higher global warming (IPCC AR6_WGI, confidence: high)
The probability of compound flooding (storm surge, extreme rainfall and/or river flow) has increased in some locations and will continue to increase due to both sea level rise and increases in heavy precipitation, including changes in precipitation intensity associated with tropical cyclones (IPCC AR6_WGI, confidence: high)
At the same time an increase in the amplitude of the seasonal cycle of atmospheric CO 2 poleward of 45°N since the early 1960s (high confidence) and a global-scale increase in vegetation greenness of the terrestrial surface since the early 1980s (IPCC AR6_WGI, confidence: high)
Reactive nitrogen, ozone and aerosols affect terrestrial vegetation and carbon cycle through deposition and effects on large-scale radiation (IPCC AR6_WGI, confidence: high)
The SRCCL concluded that continued warming will exacerbate desertification processes (medium confidence) and that ecosystems will become increasingly exposed to climates beyond those that they are currently adapted to (IPCC AR6_WGI, confidence: high)
There is low confidence in the magnitude of these changes, but the probability of crossing uncertain regional thresholds (e.g., fires, forest dieback) increases with further warming (IPCC AR6_WGI, confidence: high)
The response of biogeochemical cycles to the anthropogenic perturbation can be abrupt at regional scales, and irreversible on decadal to century time scales (IPCC AR6_WGI, confidence: high)
Global land precipitation has likely increased since 1950, with a faster increase since the 1980s (IPCC AR6_WGI, confidence: medium)
Annual global land precipitation will increase over the 21st century as global surface temperature increases (IPCC AR6_WGI, confidence: high)
Human influence has been detected in amplified surface salinity and precipitation minus evaporation (P–E) patterns over the ocean (IPCC AR6_WGI, confidence: high)
The severity of very wet and very dry events increase in a warming climate (IPCC AR6_WGI, confidence: high)
Water cycle variability and related extremes are projected to increase faster than mean changes in most regions of the world and under all emissions scenarios (IPCC AR6_WGI, confidence: high)
Over the 21st century, the total land area subject to drought will increase and droughts will become more frequent and severe (IPCC AR6_WGI, confidence: high)
Near-term projected changes in precipitation are uncertain mainly because of internal variability, model uncertainty and uncertainty in forcings from natural and anthropogenic aerosols (IPCC AR6_WGI, confidence: medium)