The concentration of CO
2
in the atmosphere has million (ppm), compared with 280 ppm in pre-
now reached an unprecedented 380 parts per industrial times.
400
DownloaD Graphic 2
CO
2
ppm
400
Atmospheric concentrations of
CO 2 over the last 10 000 years
350
350
300
1800 1900 2000
Year
Note: Measurements of CO2
300
are shown from ice cores
(symbols with different colours
for different studies) and
atmospheric samples
(red lines).
250
Source: IPCC 2007
10 000
Time (before 2005)
5 000 0
DownloaD Graphic 2
CLIMATE CHANGE 13