Not exact matches
Scientists are also trying to figure out the role that
aerosol particles — including a
component of soot known
as black carbon — play in influencing the behavior of Himalayan glaciers.
A third key hypothesis involves acidic
aerosols released at volcanic sites, such
as acid fog, dispersed throughout the atmosphere, and interacting subsequently with the finer
components of soil
as a source of widespread hydrated iron - sulfate salts.
Sulphate is not typically the dominant anthropogenic
aerosol component however, though many climate models treat it
as such.
The stratospheric
component of ECHO - G is obviously better than in an EBM but many of the important factors that lead to this being important were not considered in those runs (i.e. the volcanic forcing was input
as an equivalent TOA forcing, rather than
as absorbing lower stratospheric
aerosols, and no stratospheric ozone feedbacks on the solar forcing were included).
Some time ago I looked at the forcing
components in AR4, and found that the IPCC used
aerosols as a fudge factor.
In addition to the Ramanathan paper cited above by Chief Hydrologist, the review article by Ramanathan and Carmichael is informative in quantifying both the positive and negative forcing effects of
aerosols as a function of their
components.
In order to grasp the reasons behind the discrepancies, we investigate the effect of
aerosol sources that are not properly included in the model's emission inventory and in the boundary conditions such
as the wildfires and the desert dust
component.
In the rest of this analysis I deal with the question of to what extent the model simulations used by Shindell can be regarded
as providing reliable information about how the real climate system responds to forcing from
aerosols, ozone and other forcing
components.
Figure 10.4 of AR5, reproduced
as Figure 2 below, shows in panel (b) estimated scaling factors for three forcing
components: natural (blue bars), GHG (green bars) and «other anthropogenic» — largely
aerosols, ozone and land use change (yellow bars).
As noted earlier, the IPCC's latest report indicates that the current radiative forcing of non-carbon dioxide greenhouse gases and
aerosols effectively cancel each other, so that the net effect of all radiative forcing
components is currently roughly equal to the effect of carbon dioxide alone.
So when IPCC tells me that all anthropogenic forcing
components other than CO2 (
aerosols, albedo, land use, other GHGs, etc.) essentially cancel one another out, I have to accept this
as likely to be correct.
The sixth possible
component, only to be used
as a last resort, would be some form of geo - engineering to probably replace the
aerosols that would be lost
as carbon emissions are reduced and do not replace the short - term
aerosols.
Called ModelE, it provides the ability to simulate many different configurations of Earth System Models — including interactive atmospheric chemistry,
aerosols, carbon cycle and other tracers,
as well
as the standard atmosphere, ocean, sea ice and land surface
components.
This tells us that over this period all other anthropogenic forcing
components (
aerosols, other GHGs, land use changes, surface albedo changes, etc.) essentially cancelled one another out, so we can ignore your statement «we suspect that
aerosols caused cooling»,
as this is already compensated for by other anthropogenic warming beside CO2.
For a comprehensive GCM I can count oceans, land, atmosphere, ice, biological processes, organic and inorganic chemical processes, human - made sources and other effects, radiative energy transport, conduction and convective heat transfer, phase change, clouds and
aerosols,
as some of the important system
components, phenomena, and processes.
Theoretically, coatings of essentially non-absorbing
components such
as organic carbon or sulphate on strongly absorbing core
components such
as black carbon can increase the absorption of the composite
aerosol (e.g., Fuller et al., 1999; Jacobson, 2001a; Stier et al., 2006a), with results backed up by laboratory studies (e.g., Schnaiter et al., 2003).
[Response:
As far as I can tell — if you compensate for the affects of the southern oscillation index, volcanic aerosols, and solar variation (so you're looking at the man - made component), then temperature change since about 1975 is approximately linea
As far
as I can tell — if you compensate for the affects of the southern oscillation index, volcanic aerosols, and solar variation (so you're looking at the man - made component), then temperature change since about 1975 is approximately linea
as I can tell — if you compensate for the affects of the southern oscillation index, volcanic
aerosols, and solar variation (so you're looking at the man - made
component), then temperature change since about 1975 is approximately linear.