Figure SI 4. Cumulative CO2 emissions over the
period 2015-2100 in DICE-2016 R2, the recalibrated version for different
stabilization targets compared to estimated cumulative emissions for
different stabilization levels and probabilities as presented in IPCC SR
1.5.
In figure SI4 we present the cumulative emission budgets using DICE 2016
R2 for the 2.5°C target and compare that with the cumulative emission
budget for the same temperature target using the recalibrated DICE
model. We also use the recalibrated DICE model to estimate the carbon
budget for the 2°C target and compare that with the IPCC SR 1.5 estimate
(assuming a 50% probability of meeting the target). It shows that our
recalibrated DICE model gives results that are in line with the IPCC
estimate. In the same figure we also show the carbon budget from IPCC SR
1.5 for the 2°C target assuming a 67% probability of meeting the target
and the 1.5°C (assuming a 50% probability of meeting the target). It
may be noted that the DICE 2016 R2 carbon budget for meeting the 2.5°C
is lower than the IPCC SR 1.5 estimate for the carbon budget for the
1.5°C target.
The CO2 emission budgets presented in figure SI4 for the
IPCC cases are from table 2.2 in IPCC SR1.5 (Rogelj et al, 2018). These
budgets refer to the period 2018 and onwards, while we present budgets
for the period 2015-2100. Thus, we have added an estimated 120
GtCO2 to the IPCC budget in order to include the
emissions that took place over the period 2015-2017.
Finally, we compare our estimated temperature to the average temperature
during the period 1850-1900 when assessing the temperature stabilization
targets. This is done in order to ensure comparability with the approach
taken in DICE 2016 R2 where the surface temperature level is given in
relation to the level in the year 1900. Further, the estimates of
cumulative CO2 emissions compatible with different
stabilization levels presented in IPCC SR 1.5 are based on temperature
anomalies relative to the estimated global annual average surface
temperature over the period 1850-1900 (Rogelj et al, 2018).