The portion 
of global land experiencing detectable changes in seasonal mean 
precipitation is projected to increase (medium conﬁdence) with more 
variable precipitation and surface water ﬂows over most land regions 
within seasons (high conﬁdence) and from year to year (medium 
conﬁdence). Many changes due to past and future GHG emissions are 
irreversible118 on centennial to millennial time scales, especially in the 
ocean, ice sheets and global sea level (see 3.1.3). Ocean acidiﬁcation 
(virtually certain), ocean deoxygenation (high conﬁdence) and global 
mean sea level (virtually certain) will continue to increase in the 21st century, 
at rates dependent on future emissions. {WGI SPM B.2, WGI SPM B.2.2, 
WGI SPM B.2.3, WGI SPM B.2.5, WGI SPM B.3, WGI SPM B.3.1, 
WGI SPM B.3.2, WGI SPM B.4, WGI SPM B.5, WGI SPM B.5.1, WGI SPM B.5.3, 
WGI Figure SPM.8} (Figure 3.1)
With further global warming, every region is projected to 
increasingly experience concurrent and multiple changes 
in climatic impact-drivers. Increases in hot and decreases in 
cold climatic impact-drivers, such as temperature extremes, are 
projected in all regions (high conﬁdence). At 1.5°C global warming, 
heavy precipitation and ﬂooding events are projected to intensify 
and become more frequent in most regions in Africa, Asia (high 
conﬁdence), North America (medium to high conﬁdence) and Europe 
(medium conﬁdence).