Environmental Engineering Reference
In-Depth Information
Fig. 1
Atmospheric
concentrations of CO
2
(
a
),
CH
4
(
b
) and N
2
O (
c
) over
the last 10,000 years (large
panels) and since 1750 (inset
panels). Measurements
are shown from ice cores
(symbols with different
colours for different studies)
and atmospheric samples (
red
lines
). The corresponding
radiative forcings relative to
1750 are shown on the right
hand axes of the large panels.
Data source
IPCC (
2007a
)
(a)
(b)
(c)
Time (before 2005)
Halocarbons have increased from a near-zero pre-industrial background con-
centration, and the increase is primarily due to human activities. The atmospheric
concentrations of many halocarbon gases with ozone depleting and global warm-
ing potential (e.g. CFCl
3
and CF
2
Cl
2
) have been either increasing more slowly
or even decreasing since 1995. This happened in response to reduced emissions
