| No. Adding more CO2 to the atmosphere will cause surface temperatures to continue to
increase. As the atmospheric concentrations of CO2 increase, the addition of extra CO2
becomes progressively less effective at trapping Earth’s energy, but surface temperature
will still rise. Our understanding of the physics by which CO2 affects Earth’s energy balance is confirmed by laboratory
measurements, as well as by detailed satellite and surface observations of the emission and absorption
of infrared energy by the atmosphere. Greenhouse gases absorb some of the infrared energy that Earth
emits in so-called bands of stronger absorption that occur at certain wavelengths. Different gases absorb
energy at different wavelengths. CO2 has its strongest heat-trapping band centred at a wavelength of 15
micrometres (millionths of a metre), with wings that spread out a few micrometres on either side. There
are also many weaker absorption bands. As CO2 concentrations increase, the absorption at the centre of
the strong band is already so intense that it plays little role in causing additional warming. However, more
energy is absorbed in the weaker bands and in the wings of the strong band, causing the surface and
lower atmosphere to warm further. |