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Section 4
Section 1
Section 4
Section 4 : Near-Term Responses in a Changing Climate
4.1 The Timing and Urgency of Climate Action
The magnitude and rate of climate change and associated risks 
depend strongly on near-term mitigation and adaptation actions 
(very high conﬁdence). Global warming is more likely than not to reach 
1.5°C between 2021 and 2040 even under the very low GHG emission 
scenarios (SSP1-1.9), and likely or very likely to exceed 1.5°C under 
higher emissions scenarios141. Many adaptation options have medium 
or high feasibility up to 1.5°C (medium to high conﬁdence, depending 
on option), but hard limits to adaptation have already been reached 
in some ecosystems and the effectiveness of adaptation to reduce 
climate risk will decrease with increasing warming (high conﬁdence). 
Societal choices and actions implemented in this decade determine the 
extent to which medium- and long-term pathways will deliver higher or 
lower climate resilient development (high conﬁdence). Climate resilient 
development prospects are increasingly limited if current greenhouse 
gas emissions do not rapidly decline, especially if 1.5°C global warming 
is exceeded in the near term (high conﬁdence). Without urgent, effective 
and equitable adaptation and mitigation actions, climate change 
increasingly threatens the health and livelihoods of people around 
the globe, ecosystem health, and biodiversity, with severe adverse 
consequences for current and future generations (high conﬁdence). 
{WGI SPM B.1.3, WGI SPM B.5.1, WGI SPM B.5.2; WGII SPM A, WGII 
SPM B.4, WGII SPM C.2, WGII SPM C.3.3, WGII Figure SPM.4, WGII SPM 
D.1, WGII SPM D.5, WGIII SPM D.1.1 SR1.5 SPM D.2.2}.