Urbanisation increases hot extremes (very high 
conﬁdence) and precipitation runoff intensity (high conﬁdence). 
Increasing urbanisation in low-lying and coastal zones will be a major 
driver of increasing exposure to extreme riverﬂow events and sea level 
rise hazards, increasing risks (high conﬁdence) (Figure 4.3). Vulnerability 
will also rise rapidly in low-lying Small Island Developing States and 
atolls in the context of sea level rise (high conﬁdence) (see Figure 3.4 and 
Figure 4.3). Human vulnerability will concentrate in informal settlements 
and rapidly growing smaller settlements; and vulnerability in rural 
areas will be heightened by reduced habitability and high reliance on 
climate-sensitive livelihoods (high conﬁdence). Human and ecosystem 
vulnerability are interdependent (high conﬁdence). Vulnerability to 
climate change for ecosystems will be strongly inﬂuenced by past, 
present, and future patterns of human development, including from 
unsustainable consumption and production, increasing demographic 
pressures, and persistent unsustainable use and management of 
149 See Annex I: Glossary. The main internal variability phenomena include El Niño–Southern Oscillation, Paciﬁc Decadal Variability and Atlantic Multi-decadal Variability through 
their regional influence. The internal variability of global surface temperature in any single year is estimated to be about ±0.25°C (5 to 95% range, high confidence). 
{WGI SPM footnote 29, WGI SPM footnote 37}
150 Based on 2500-year reconstructions, eruptions with a radiative forcing more negative than –1 Wm-2, related to the radiative effect of volcanic stratospheric aerosols in the 
literature assessed in this report, occur on average twice per century. {WGI SPM footnote 38}
land, ocean, and water (high conﬁdence). Several near-term risks can 
be moderated with adaptation (high conﬁdence).