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TFE.9, Table 1 - Extreme weather and climate events: Global-scale assessment of recent observed changes, human contribution to the changes and projected further changes for the early (2016–2035) and late (2081–2100) 21st century

Phenomenon and direction of trend Assessment that changes occurred (typically
since 1950 unless otherwise indicated)
Assessment of a human
contribution to observed changes
Likelihood of further changes
Early 21st century Late 21st century
* The direct comparison of assessment findings between reports is difficult. For some climate variables, different aspects have been assessed, and the revised guidance note on uncertainties has been used for the SREX and AR5. The availability of new information, improved scientific understanding, continued analyses of data and models, and specific differences in methodologies applied in the assessed studies, all contribute to revised assessment findings.

Notes:
a Attribution is based on available case studies. It is likely that human influence has more than doubled the probability of occurrence of some observed heat waves in some locations.
b Models project near-term increases in the duration, intensity and spatial extent of heat waves and warm spells.
c In most continents, confidence in trends is not higher than medium except in North America and Europe where there have been likely increases in either the frequency or intensity of heavy precipitation with some seasonal and/or regional variation. It is very likely that there have been increases in central North America.
d The frequency and intensity of drought has likely increased in the Mediterranean and West Africa and likely decreased in central North America and north-west Australia.
e AR4 assessed the area affected by drought.
f SREX assessed medium confidence that anthropogenic influence had contributed to some changes in the drought patterns observed in the second half of the 20th century, based on its attributed impact on precipitation and temperature changes. SREX assessed low confidence in the attribution of changes in droughts at the level of single regions.
g There is low confidence in projected changes in soil moisture.
h Regional to global-scale projected decreases in soil moisture and increased agricultural drought are likely (medium confidence) in presently dry regions by the end of this century under the RCP8.5 scenario. Soil moisture drying in the Mediterranean, Southwest USA and southern African regions is consistent with projected changes in Hadley circulation and increased surface temperatures, so there is high confidence in likely surface drying in these regions by the end of this century under the RCP8.5 scenario.
i There is medium confidence that a reduction in aerosol forcing over the North Atlantic has contributed at least in part to the observed increase in tropical cyclone activity since the 1970s in this region.
j Based on expert judgment and assessment of projections which use an SRES A1B (or similar) scenario.
k Attribution is based on the close relationship between observed changes in extreme and mean sea level.
l There is high confidence that this increase in extreme high sea level will primarily be the result of an increase in mean sea level. There is low confidence in region-specific projections of storminess and associated storm surges.
m SREX assessed it to be very likely that mean
Warmer and/or fewer
cold days and nights
over most land areas
Very likely {2.6}
Very likely
Very likely
Very likely {10.6}
Likely
Likely
Likely {11.3} Virtually certain {12.4}
Virtually certain
Virtually certain
Warmer and/or more
frequent hot days and
nights over most land areas
Very likely {2.6}
Very likely
Very likely
Very likely {10.6}
Likely
Likely (nights only)
Likely {11.3} Virtually certain {12.4}
Virtually certain
Virtually certain
Warm spells/heat waves.
Frequency and/or duration
increases over most
land areas
Medium confidence on a global scale
Likely in large parts of Europe, Asia and Australia {2.6}
Medium confidence in many (but not all) regions
Likely
Likelya {10.6}
Not formally assessed
More likely than not
Not formally assessedb
{11.3}
Very likely {12.4}
Very likely
Very likely
Heavy precipitation events.
Increase in the frequency,
intensity, and/or amount
of heavy precipitation
Likely more land areas with increases than decreasesc
{2.6}
Likely more land areas with increases than decreases
Likely over most land areas
Medium confidence
{7.6, 10.6}
Medium confidence
More likely than not
Likely over many land areas
{11.3}
Very likely over most of the mid-latitude land
masses and over wet tropical regions {12.4}
Likely over many areas
Very likely over most land areas
Increases in intensity
and/or duration of drought
Low confidence on a global scale
Likely changes in some regionsd {2.6}
Medium confidence in some regions
Likely in many regions, since 1970e
Low confidence {10.6}
Medium confidencef
More likely than not
Low confidenceg {11.3} Likely (medium confidence) on a regional to
global scaleh {12.4}
Medium confidence in some regions
Likelye
Increases in intense
tropical cyclone activity
Low confidence in long term (centennial) changes
Virtually certain in North Atlantic since 1970 {2.6}
Low confidence
Likely in some regions, since 1970
Low confidencei {10.6}
Low confidence
More likely than not
Low confidence
{11.3}
More likely than not in the Western North Pacific
and North Atlanticj {14.6}
More likely than not in some basins
Likely
Increased incidence and/or
magnitude of extreme
high sea level
Likely (since 1970) {3.7}
Likely (late 20th century)
Likely
Likelyk {3.7}
Likelyk
More likely than notk
Likelyl {13.7} Very likelyl {13.7}
Very likelym
Likely

TFE.9, Table 1 - Extreme weather and climate events: Global-scale assessment of recent observed changes, human contribution to the changes and projected further changes for the early (2016–2035) and late (2081–2100) 21st century. Bold indicates where the AR5 (black) provides a revised* global-scale assessment from the Special Report on Managing the Risk of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX, blue) or AR4 (red). Projections for early 21st century were not provided in previous assessment reports. Projections in the AR5 are relative to the reference period of 1986–2005, and use the new RCP scenarios unless otherwise specified. See the Glossary for definitions of extreme weather and climate events.

Source: IPCC  Climate Change 2013: Technical Summary, p.110

Related publication:
Climate Change (2013) homeClimate Change: 2013 IPCC Update
Other Figures & Tables on this publication:

Box TS.1 - Treatment of Uncertainty

Figure TS.1 - Multiple complementary indicators of a changing global climate

Figure TS.2 - Change in surface temperature over 1901–2012

Figure TS.3 - Ice loss in Greenland and Antarctica

TFE.1, Figure 1 - Changes in sea surface salinity

TFE.1, Figure 2 - Changes in precipitation over 20th century

TFE.1, Figure 3 - Projected changes in precipitation, 21st century

TFE.2, Figure 1 - Comparison of observed trends with previous projections.

TFE.2, Figure 2 - Compilation of paleo sea level data

Figure TS.4 - Annual anthropogenic CO2 emissions

Figure TS.5 - Atmospheric composition.

Figure TS.6 - Radiative forcing and Effective radiative forcing of climate change during the Industrial Era

Figure TS.7 - Radiative forcing of climate change during the Industrial Era shown by emitted components from 1750 to 2011

Figure TS.8 - (Upper) Global anthropogenic present-day emissions weighted by the Global Warming Potential and the Global Temperature change Potential

Figure TS.9 - Global temperatures with and without anthropogenic forcing

Box TS.3, Figure 1 - Trends in temperature changes for the last few decades.

TFE.3, Figure 1 - Observed globally and annually averaged CO2 concentrations in parts per million since 1950 compared with projections from the previous IPCC assessments. Observed global annual CO2 concentrations are shown in dark blue.

Figure TS.10 - Likely ranges of warming trends.

TFE.4, Figure 1 - The Earth’s energy budget from 1970 through 2011

TFE.5, Figure 1 - Atlantic Meridional Overturning Circulation

Figure TS.11 - Simulated and observed 1951–2011 trends in the Southern Annular Mode index by season

Figure TS.12 - Comparison of observed and simulated change in the climate system, at regional scales and global scales

Box TS.4, Figure 1 - Summary of how well the current-generation climate models simulate important features of the climate of the 20th century

Box TS.5, Figure 1 - Simulations and reconstructions of the climate of the last millennium.

Box TS.6, Figure 1 - Modeled patterns of temperature and precipitation changes.

TFE.6, Figure 1 - Climate sensitivity

TFE.6, Figure 2 - Climate response

Figure TS.13 - Decadal prediction forecast quality of several climate indices.

Figure TS.14 - Synthesis of near-term projections of global mean surface air temperature

Figure TS.15 - Annual mean temperature change

Figure TS.16 - Maps of multi-model results for the scenarios in 2081–2100 of average percent change in mean precipitation

Figure TS.17 - Northern Hemisphere sea ice extent in September over the late 20th century and the whole 21st century for the scenarios

Figure TS.18 - Northern hemisphere snow cover and permafrost area over the 21st century

Figure TS.19 - Compatible fossil fuel emissions simulated by the CMIP5 models for the four RCP scenarios

Figure TS.20 - Time series (model averages and minimum to maximum ranges) and maps of multi-model surface ocean pH

TFE.7, Figure 1 - Percentage of CO2 pulse remaining in the atmosphere after a number of years

TFE.7, Figure 2 - Comparison of carbon cycle feedback metrics between the ensemble of seven General Circulation Models

Figure TS.21 - Projections of global mean sea level

Figure TS.22 - Projections from process-based models of global mean sea level

Figure TS.23 - Sea level rise in different scenarios

TFE.8, Figure 1 - Temperature increases in different scenarios

Figure TS.24 - Future change in monsoon statistics between the present-day (1986–2005) and the future (2080–2099)

Figure TS.25 - Standard deviation in CMIP5 multi-model ensembles of sea surface temperature variability over the eastern equatorial Pacific Ocean

Figure TS.26 - Projected changes in tropical cyclone statistics.

TFE.9, Figure 1 - Global projections of the occurrence of extreme events

Table TS.1 - Projected change in global mean surface air temperature and global mean sea level rise for the mid- and late 21st century relative to the reference period of 1986–2005.

Table TS.2 - Overview of projected regional changes and their relation to major climate phenomena.

TFE.9, Table 1 - Extreme weather and climate events: Global-scale assessment of recent observed changes, human contribution to the changes and projected further changes for the early (2016–2035) and late (2081–2100) 21st century