Radiative Forcing

To start with, I will give you a short introduction, how our atmosphere works and how climate warming appears in this model, by sharing this video.

To measure the human impact on climate change, the IPCC uses the concept of radiative forcing.

„The change in net (down minus up) irradiance (solar plus longwave; in W m–2) at the tropopause after allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values“ Ramaswamy et al. (2001)

With this concept we can try to measure the importance of the greenhouse gases to radiative forcing and therefore to our climate. ( 5^th IPCC report 2014)

I found a good graph in the 4^th IPCC report 2007, which shows, how the greenhouse gases and other human driven factors have changed since 1750 and in particular how these changes influencing the radiative forcing.

Figure 5: 4^th IPCC report 2007

Although, there is an increase in radiative forcing about 1,6 W m-2, there are some human impacts, like an increase in aerosols, which decrease the radiative forcing. In addition, concerning my last post about solar variability, you can see at this graph how small the influence of the solar irradiance to our climate really is.

To conclude the first part of my blog, nearly every argument in the video, at shared at my first post, have I proofed as wrong, except for one. Why does the air temperature did not rise in the last 15 years? I just found an article in a German newspaper “Der Spiegel”, which is describing a break in warming over Eurasia in the last 15 years. There are only speculations, why this is happening. One theory is saying that the Pacific may have absorbed the warmth or another theory is seeing the reason in the influence of clouds. Low clouds can cool the air and high clouds can warm it.

Hopefully, I am going to find out in my next post.