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Long-Term Climate and Development Futures
Section 3
3.1.2 Impacts and Related Risks
For a given level of warming, many climate-related risks are 
assessed to be higher than in AR5 (high conﬁdence). Levels of 
risk120 for all Reasons for Concern121 (RFCs) are assessed to become high 
to very high at lower global warming levels compared to what was 
assessed in AR5 (high conﬁdence). This is based upon recent evidence 
of observed impacts, improved process understanding, and new 
knowledge on exposure and vulnerability of human and natural 
systems, including limits to adaptation. Depending on the level 
of global warming, the assessed long-term impacts will be up to 
multiple times higher than currently observed (high confidence) for 
127 identiﬁed key risks, e.g., in terms of the number of affected people 
and species. Risks, including cascading risks (see 3.1.3) and risks from 
overshoot (see 3.3.4), are projected to become increasingly severe 
with every increment of global warming (very high confidence). 
{WGII SPM B.3.3, WGII SPM B.4, WGII SPM B.5, WGII 16.6.3; SRCCL SPM A5.3} 
(Figure 3.2, Figure 3.3)
Climate-related risks for natural and human systems are higher for 
global warming of 1.5°C than at present (1.1°C) but lower than at 2°C 
(high conﬁdence) (see Section 2.1.2). Climate-related risks to health, 
livelihoods, food security, water supply, human security, and economic 
growth are projected to increase with global warming of 1.5°C. In 
terrestrial ecosystems, 3 to 14% of the tens of thousands of species 
assessed will likely face a very high risk of extinction at a GWL of 1.5°C. 
Coral reefs are projected to decline by a further 70–90% at 1.5°C of 
global warming (high conﬁdence).