351.3 Methods
Most of the figures are composites formed by combining data from publicly avail-
able data archives. Here we provide details on webpage addresses of these archives,
citations to the scientific papers that describe the measurements, as well as details
regarding how the data has been processed. Electronic copies of the figures are avail-
able on-line at http://parisbeaconofhope.org.
Figure 1.1 shows estimates of the global mean surface temperature anomaly
(ΔT) relative to the pre-industrial baseline and the mixing ratio of atmospheric CO 2 ,
plotted using a logarithmic scale. The figure is broken up into six intervals, denoted
using Era. Sources of ΔT and CO 2 for each Era are described below.
Era 1, ΔT is based on two data records:
(i) 1850 to present: the HadCRUT4.4.0.0 global, annual mean temperature record
based on thermometer measurements, provided by the Climatic Research Unit
(CRU) of the University of East Anglia, in conjunction with the Hadley Centre
of the United Kingdom Met Office (Jones et al. 2012 ), archived at:
http://www.metoffice.gov.uk/hadobs/hadcrut4/data/4.4.0.0/time_series/
HadCRUT.4.4.0.0.annual_ns_avg.txt
Column 2 of this file tabulates ΔT relative to their 1961–1990 baseline. We have
added 0.3134 °C to each data point, in order to place the measurements on the
1850 1900 1950 2000 2050 2100∆RF
(W
m–2)
Past:
Aerosol forcing
similar strength
to GHG forcingFuture:
GHG forcing
will dominateAerosolsN 2 O
CH 4
CO 2
Total GHG43210–1RCP 4.5
Fig. 1.10 The rise and fall
of RF due to aerosols.
Time series of radiative
forcing of climate (ΔRF)
due to CO 2 , CH 4 , N 2 O, and
all anthropogenic GHGs,
from 1850 to 2100, based
on the RCP 4.5 scenario
(Meinshausen et al. 2011 )
(top) and 71 plausible
scenarios for total ΔRF
due to anthropogenic
aerosols (combination of
the aerosol direct effect
and the aerosol-cloud
interaction) from Smith
and Bond ( 2014 ) (bottom).
See Methods for further
information
1.3 Methods