Geoscience Reference
In-Depth Information
Future global temperatures and sea level
Between 32 and 39 AOGCMs have been run for each of the RCPs for the IPCC 2013 re-
port, to produce scenarios of global temperature and sea level changes that may occur by
2100. This is a significant change from the IPCC 2001 report, in which only seven models
were used. These climate models suggest that the global surface temperature between 2016
and 2035 will rise by between 0.3°C and 0.7°C relative to the average of 1986‒2005. The
global temperatures rise for the average of 2081‒2100 again relative to the average of
1986‒2005 will be heavily dependent on the RCP we follow (see
Table 3
). If the realistic
RCPs are considered the global temperatures could rise between 1.1 and 4.8°C in the last
two decades of the century (see
Figure 17
). With the rise of 0.8°C already, this would rep-
resent a total rise of 1.9°C to 5.6°C. An added confusion is that the IPCC Fourth Assess-
ment report in 2007 report global temperatures at 2100 instead of an average of
2081‒2100. They reported using the best estimates for the original six emission scenarios,
a range between 1.8°C and 4°C by 2100. This compares to the IPCC FifthAssessment Re-
port 2013's final mean global temperature for RCP8.5 and RCP4.5 of between 1.9°C and
4.1°C by 2100. A strikingly similar set of results.
Table 3
. Temperature and sea level projection by Representative Concentration Pathway
Representative Concentration Path-
way
Global temperature change (°C)
2081‒2100
Global sea level rise (m)
2081‒2100
RCP8.5
2.6 to 4.8 (mean 3.7)
0.45 to 0.82 (mean 0.63)
RCP6
1.4 to 3.1 (mean 2.2)
0.33 to 0.63 (mean 0.48)
RCP4.5
1.1 to 2.6 (mean 1.8)
0.32 to 0.63 (mean 0.47)
RCP2.6 or RCP3PD
0.3 to 1.7 (mean 1.0)
0.26 to 0.55 (mean 0.40)
