75
Long-Term Climate and Development Futures
Section 3
Salt
marshes
Rocky
shores
Seagrass
meadows
Epipelagic
Warm-water
corals
Kelp
forests
AR5 AR6
AR5 AR6
AR5 AR6
AR5 AR6
AR5 AR6
Global surface temperature change
relative to 1850–1900
Global Reasons for Concern (RFCs) 
in AR5 (2014) vs. AR6 (2022)
°C
0
1
1.5
2
3
4
5
0
1
1.5
2
3
4
5
°C
0
–1
2000 2015
2050
2100
1
2
3
4
5
very low
low
intermediate
high
very high
••••
••••
•••
••••
•••
••
•••
••
••
•••
••
•
••
••
••
damage
Wildﬁre
•••
••
••
Dryland
water 
scarcity
•••
••
••
0
2
3
4
1.5
1
Incomplete
adaptation
Proactive
adaptation
Limited
adaptation
••
••
••
••
••
Heat-related morbidity and mortality
high
Challenges to Adaptation
low
•••
••••
••••
•••
•••
•••
••••
•••
•••
•••
••
••
••
••
•
•••
••
••
Conﬁdence level
assigned to 
transition range
midpoint of transition
Risk/impact
Low
Very high
Very high
High
Moderate
Undetectable
•
•••
••
••••
Transition range
°C
°C
Permafrost 
degradation
•••
•••
••
e.g.