These emissions have led to increases in the atmospheric 
concentrations of several GHGs including the three major well-mixed 
GHGs CO2, CH4 and N2O (panel (b), annual values). To indicate their 
relative importance each subpanel’s vertical extent for CO2, CH4 and 
N2O is scaled to match the assessed individual direct effect (and, 
in the case of CH4 indirect effect via atmospheric chemistry impacts 
on tropospheric ozone) of historical emissions on temperature 
change from 1850–1900 to 2010–2019. This estimate arises from 
an assessment of effective radiative forcing and climate sensitivity. 
The global surface temperature (shown as annual anomalies from 
a 1850–1900 baseline) has increased by around 1.1°C since 
1850–1900 (panel (c)). The vertical bar on the right shows the 
estimated temperature (very likely range) during the warmest 
multi-century period in at least the last 100,000 years, which 
occurred around 6500 years ago during the current interglacial 
period (Holocene). Prior to that, the next most recent warm period 
was about 125,000 years ago, when the assessed multi-century 
temperature range [0.5°C to 1.5°C] overlaps the observations of 
the most recent decade. These past warm periods were caused 
by slow (multi-millennial) orbital variations. Formal detection and 
attribution studies synthesise information from climate models 
and observations and show that the best estimate is that all the 
warming observed between 1850–1900 and 2010–2019 is caused 
by humans (panel (d)). The panel shows temperature change 
attributed to: total human inﬂuence; its decomposition into changes 
in GHG concentrations and other human drivers (aerosols, ozone 
and land-use change (land-use reﬂectance)); solar and volcanic 
drivers; and internal climate variability. Whiskers show likely ranges.