Historic Minuscule Simulations - Climate Change: Identification and Projections - page 101

Figure 9.2. CMIP5:Complete observations and simulations
(upper lines), Natural forcing only (lower line)

1.5

Observations
Models using both natural and anthropogenic forcings.
Models using only natural forcings

1

0.5

0

-0.5

1850 1900 1950 2000

Figure 9.3. Simulation of identified models (period 1850-2013)

Both figures show the averages of the simulations, respectively with and
without anthropogenic contribution. The conclusions are incompatible: for
the IPCC, warming is almost entirely attributed to the anthropogenic factor,
with the natural factors being dominated by volcanism. If the identified
models are to be believed, the majority results from natural factors, and more
specifically, from solar activity.

More precisely, for a warming of around 0.8 degrees since the start of the
20 th Century, a visual evaluation gives the following distribution (in 2014).

According to the IPCC “knowledge-based” models:
+0.2 ° C results from solar and volcanic activity;
+0.8°C from human activity;
-0.2°C from natural random fluctuations.