Editing IPCC:AR6/WGI/TS (section)

===== TS.4.3.2.2 Asia =====

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Due to the high climatological and geographical heterogeneity of Asia, some assessment findings below are summarized over five sub-continental areas comprising one or more of the AR6 WGI reference regions (Box TS.12): East Asia (EAS+ECA), North Asia (WSB+ESB+RFE), South Asia (SAS), South East Asia (SEA) and South West Asia (ARP+WCA).

'''Additional regional changes in Asia, besides those features described in Section TS.4.3.1, include historical trends of annual precipitation that show considerable regional differences ( ''high confidence'' ). East Asian Monsoon precipitation has changed, with drying in the north and wetting in the south since the 1950s, and annual mean precipitation totals ''very likely'' have increased over most territories of North Asia since the mid-1970s ( ''high confidence'' ). South Asian summer monsoon precipitation decreased over several areas since the mid-20th century ( ''high confidence'' ) but is ''likely'' to increase during the 21st century, with enhanced interannual variability. (Box TS.13)''' '''Increases in precipitation and river floods are projected over much of Asia: in the annual mean precipitation in East, North, South and South East Asia ( ''high confidence'' ); for extremes in East, South, West Central, North and South East Asia ( ''high confidence'' ) and Arabian Peninsula ( ''medium confidence'' ); and for river floods in East, South and South East Asia and East Siberia ( ''medium confidence'' ). Aridity in East and West Central Asia is projected to increase, especially beyond the middle of the 21st century and global warming levels beyond 2°C ( ''medium confidence'' ). Fire weather seasons are projected to lengthen and intensify everywhere except South East Asia, Tibetan Plateau and Arabian Peninsula ( ''medium confidence'' ).''' '''Surface wind speeds have been decreasing in Asia ( high confidence ), but there is a large uncertainty in future trends, with medium confidence that mean wind speeds will decrease in North Asia, East Asia and Tibetan Plateau and that tropical cyclones will have decreasing frequency and increasing intensity overall in South East and East Asia.''' '''Over North Asia, increases in permafrost temperature and its thawing have been observed over recent decades ( ''high confidence'' ). Future projections indicate continuing decline in seasonal snow duration, glacial mass, and permafrost area by mid-century ( ''high confidence'' ). Snow-covered areas and snow volumes will decrease in most regions of the Hindu Kush Himalaya (HKH) during the 21st century, and snowline elevations will rise ( ''high confidence'' ) and glacier volumes are ''likely'' to decline with greater mass loss in higher CO <sub>2</sub> emissions scenarios. Heavy snowfall is increasing in East Asia and North Asia ( ''medium confidence'' ) but with limited evidence on future changes in hail and snow avalanches.''' '''Links to chapters 2.3, 8.3, 8.4, 9.5, 9.6, 10.6, Box 10.4, 11.4, 11.5, 11.7, 11.9, 12.4.2, Atlas.3.1, Atlas.5, Atlas.5.2, Atlas.5.3, Atlas.5.4, Atlas.5.5'''
In addition to the main changes summarized above and in Section TS.4.3.1, further details are given below.

'''Heat and cold:''' Over all regions of Asia, observed and projected increases in mean temperature and a shift toward heat extreme characteristics are broadly similar to the generic pattern described in Section TS.4.3.1. Over South East Asia, annual mean surface temperature will ''likely'' increase by a slightly smaller amount than the global average. Links to chapters Atlas.5.4.4

'''Wet and dry:''' Over East Asia, historical trends of annual precipitation show considerable regional differences but with increases over north-west China and South Korea ( ''high confidence'' ). Daily precipitation extremes have increased over part of the region ( ''high confidence'' ). Extreme hydrological drought frequency has increased in a region extending from south-west to north-east China, with projected increases of agricultural and ecological drought for 4°C GWL and fire weather for 2°C and above ( ''medium confidence'' ) ''.'' Links to chapters 8.3.2, 8.4.2, 11.4.4, 11.4.5, 11.9, 12.4.2.2, Atlas.5.1.2

Over North Asia, annual mean precipitation totals have ''very likely'' increased, causing more intense flooding events, and there is ''medium confidence'' that the number of dry days has decreased. Concurrently, total soil moisture is projected to decline extensively ( ''medium confidence'' ). Links to chapters 8.3.1.3, 8.4.1.6, 11.4.5, 11.5.2, 11.5.5, 12.4.2.2, Atlas.5.2.2

Over South Asia, the summer monsoon precipitation decreased over several areas since the mid-20th century ( ''high confidence'' ), while it increased in parts of the western HKH and decreased over eastern-central HKH ( ''medium confidence'' ). The frequency of heavy precipitation and flood events has increased over several areas during the last few decades ( ''medium confidence'' ). Links to chapters 8.3.1.3, 8.3.2.4.1, 8.4.1.5, 8.4.2.4.1, 10.6.3.3, 10.6.3.5, 10.6.3.6, 10.6.3.8, Cross-Chapter Box 10.4, 11.4.1, 11.4.2, 11.4.5, 11.5.5, 12.4.2.2, Box 10.4, [[IPCC:Wg1:Chapter:Atlas|Atlas]] 5.3.2

Over South East Asia, mean precipitation trends are not spatially coherent or consistent across datasets and seasons ( ''high confidence'' ). Most of the region has experienced an increase in rainfall intensity but with a reduced number of wet days ( ''medium confidence'' ). Rainfall is projected to increase in the northern parts of South East Asia and decrease in areas in the Maritime Continent ( ''medium confidence'' ). Links to chapters 8.4.1, 11.4.2, 11.5.5, 11.9, 12.4.2.2, Atlas.3.1, Atlas.5.4.2, Atlas.5.4.4

Over South West Asia, an observed annual precipitation decline over the Arabian Peninsula since the 1980s of 6.3 mm per decade is contrasted with observed increases between 1.3 mm and 4.8 mm per decade during 1960–2013 over the elevated part of eastern West Central Asia ( ''very high confidence'' ), along with an increase of the frequency and intensity of extreme precipitation. Links to chapters Figure 8.19, Figure 8.20, 8.3.1.6, 8.4.1.6, 11.9, Table 11.2A, 12.4.2.2, Atlas.5.5

'''Wind:''' Over East Asia, the terrestrial near-surface wind speed has decreased and is projected to decrease further in the future ( ''medium confidence'' ). Since the mid 1980’s, there has been an increase in the number and intensification rate of intense TCs ( ''medium confidence'' ), with a significant north-westward shift in tracks and a northward shift in their average latitude, increasing exposure over East China, the Korean Peninsula and the Japanese Archipelago ( ''medium confidence'' ). Links to chapters 11.7.1, 12.4.2.3

Over North Asia, there is ''medium confidence'' for a decreasing trend in wind speed during 1979–2018 and for projected continuing decreases of terrestrial near-surface wind speed. Links to chapters 2.3.1.4.4, 12.4.2.3

Over South East Asia, although there is no significant long-term trend in the number of TCs, fewer but more extreme TCs have affected the Philippines during 1951–2013. Links to chapters 11.7.4, 12.4.2.3

'''Snow and ice:''' Over East Asia, decreases have been observed in the frequency, and increases in the mean intensity, of snowfall in north-western, north-eastern and south-eastern China and the eastern Tibetan Plateau since the 1960s. Heavy snowfall is projected to occur more frequently in some parts of Japan ( ''medium confidence'' ). Links to chapters 12.4.2.4, Atlas.5.1.2

Over North Asia, seasonal snow duration and extent have decreased in recent decades ( ''high confidence'' ), and maximum snow depth ''likely'' has increased since the mid-1970s, particularly over the south of the Russian Far East. Links to chapters 2.3.2.5, 8.3.1.7.2, 9.5, 12.4.2.4, Atlas.5.2, Atlas.5.4

Over South Asia, snow cover has reduced over most of the HKH since the early 21st century, and glaciers have thinned, retreated, and lost mass since the 1970s ( ''high confidence'' ), although the Karakoram glaciers have either slightly gained mass or are in an approximately balanced state ( ''medium confidence'' ). Links to chapters 8.3.1.7.1, Cross-Chapter Box 10.4

Over South West Asia, mountain permafrost degradation at high altitudes has increased the instability of mountain slopes in the past decade ( ''medium confidence'' ). More than 60% of glacier mass in the Caucasus is projected to disappear under RCP8.5 emissions by the end of the 21st century ( ''medium confidence'' ). Links to chapters 9.5.1, 9.5.3, 12.4.2.4

'''Coastal and oceanic:''' Over the last three decades, relative sea level has increased at a rate higher than GMSL around Asia ( ''high confidence'' ). Gross coastal area loss and shoreline retreat has been observed over 1984–2015, but with localized shoreline progradation in the Russian Far East, East and South East Asia. Links to chapters 12.4.2.5

Projections show that regional mean sea level continues to rise ( ''high confidence'' ), ranging from 0.4–0.5 m under SSP1-2.6 to 0.8–1.0 m under SSP5-8.5 for 2081–2100 relative to 1995–2014 (median values). This will contribute to more frequent coastal flooding and higher ETWL in low-lying areas and coastal erosion along sandy beaches ( ''high confidence'' ). There is ''high confidence'' that compound effects of climate change, land subsidence, and human factors will lead to higher flood levels and prolonged inundation in the Mekong Delta and other Asian coasts. Links to chapters 9.6.1, 9.6.3, 12.4.2.5

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