Editing IPCC:AR6/WGI/Chapter-12 (section)

==== 12.4.3.3 Wind ====

<div id="h3-47-siblings" class="h3-siblings"></div>

'''Mean wind speed:''' There is ''low confidence'' of a mean wind speed trend in the last decades ( ''low agreement'' ) ( [[#McVicar--2012|McVicar et al., 2012]] ; [[#Troccoli--2012|Troccoli et al., 2012]] ; [[#Azorin-Molina--2018|Azorin-Molina et al., 2018]] ; J. [[#Wu--2018|]] [[#Wu--2018|Wu et al., 2018]] ), as long-term measurements are not homogeneous.

In future climate scenarios wind speed trends in Australia exhibit generally weak amplitudes with ''low agreement'' among models (Figure 12.4m–o and Figure 12.SM.5) with uncertain consequences on wind power potential (CSIRO and BOM, 2015; [[#Karnauskas--2018a|Karnauskas et al., 2018a]] ; [[#Jung--2019|Jung and Schindler, 2019]] ). However, there is ''medium confidence'' that, by the end of the century, annual mean wind power will significantly increase in north-eastern Australia under RCP8.5, but there is ''low confidence'' of an increase by end-century under RCP4.5, and for any scenario by mid-century ( [[#Karnauskas--2018a|Karnauskas et al., 2018a]] ). In New Zealand, mean wind patterns are projected to become more north-easterly in summer, and westerlies to become more intense in winter ( ''low confidence'' ), in agreement with the strengthening of the Southern Hemisphere storm tracks ( [[IPCC:Wg1:Chapter:Chapter-4#4.5.1|Section 4.5.1]] ).

'''Severe wind storm:''' There is generally ''low confidence'' in observed changes in extreme winds and extratropical storms in Australasia ( [[IPCC:Wg1:Chapter:Chapter-11#11.7.2|Section 11.7.2]] ). CMIP5 projections of severe winds indicate a general increase in north-eastern Australia, and decreases in some parts in Southern and Central Australia ( ''medium confidence'' ) by the end of the century under RCP8.5 (CSIRO and BOM, 2015; [[#Kumar--2015|Kumar et al., 2015]] ; [[#Jung--2019|Jung and Schindler, 2019]] ). Elsewhere trends are diverse and vary across simulations with ''low agreement'' . Projections of changes in the 1-in-25-year return period winds (based on annual maxima) for 2074–2100 relative to 1979–2005 for RCP8.5 show an increase in tropical areas of Northern Australia ( [[#Kumar--2015|Kumar et al., 2015]] ).

In New Zealand, the frequency and magnitude of extreme winds have decreased (from 1980–2019) at 12 of 14 monitored sites and increased at two monitored sites (MfE and Stats NZ, 2020). Due to the intensification and the shift of the austral storm track by the end of the century ( [[#Yin--2005|Yin, 2005]] ), increases in extreme wind speed in New Zealand are projected over the South Island and the southern part of the North Island by mid- and end-century for all RCPs ( ''low confidence'' ) ( [[#MfE--2018|MfE, 2018]] ).

'''Tropical cyclone:''' In Australia, the number of TCs has generally declined since 1982, and the frequency of intense TCs that make landfall in north-eastern Australia has declined significantly since the 19th century ( ''medium confidence'' ) ( [[#Kuleshov--2010|Kuleshov et al., 2010]] ; [[#Callaghan--2011|Callaghan and Power, 2011]] ; [[#Holland--2014|Holland and Bruyère, 2014]] ; [[#Knutson--2019|Knutson et al., 2019]] ; CSIRO and BOM, 2020). There is ''high confidence'' that cyclones making landfall along north-eastern and northern Australian coastlines will decrease in number and ''low confidence'' of an increase in their intensities for 2°C of global warming as well as for the mid-century period with scenarios RCP4.5 and above ( [[#Roberts--2015|Roberts et al., 2015]] , 2020; [[#Bacmeister--2018|Bacmeister et al., 2018]] ; [[#Knutson--2020|Knutson et al., 2020]] ), with the amplitude of changes increasing from RCP4.5 to RCP8.5 ( [[#Bacmeister--2018|Bacmeister et al., 2018]] ). Decreases in frequency are projected for ‘east coast lows’ ( [[#Walsh--2016b|Walsh et al., 2016b]] ; [[#Dowdy--2019a|Dowdy et al., 2019a]] ).

'''Sand and dust storm:''' Australia is recognized to be the largest dust source in the Southern Hemisphere ( [[#Zheng--2016|Zheng et al., 2016]] ). Land-use and land-cover change have increased dust emissions in Australia in the past 200 years ( [[#Marx--2014|Marx et al., 2014]] ). While projections suggest a decrease in severe winds in Central and Southern Australia, changes in vegetation due to increased aridity and hydrological drought could be expected to result in increased wind erosion and dust emission across the country ( ''medium confidence'' ) ( [[#Webb--2020|Webb et al., 2020]] ).

'''In Australasia, there is''' low confidence '''in projected mean wind speeds and wind power potential, with a''' medium confidence '''increase projected only in north-eastern Australia under high emissions scenarios and by the end of the 21st century. Tropical cyclones in north-eastern and North Australia are projected to decrease in number''' ( high confidence ''') while their intensity is projected to increase''' ( low confidence ''').'''

<div id="12.4.3.4" class="h3-container"></div>

<span id="snow-and-ice-3"></span>