For the period after 1974,... there is no evidence for any non-magnetic
change in the solar irradiance on time scales longer than about a day.»
Not exact matches
-LSB-...] This is what the IPCC (the world's most authoritative body
on climate
change) had to say
on solar forcing
in its most recent report «Continuous monitoring of total
solar irradiance now covers the last 28 years.
[T] he idea that the sun is currently driving climate
change is strongly rejected by the world's leading authority on climate science, the U.N.'s Intergovernmental Panel on Climate Change, which found in its latest (2013) report that «There is high confidence that changes in total solar irradiance have not contributed to the increase in global mean surface temperature over the period 1986 to 2008, based on direct satellite measurements of total solar irradiance.&
change is strongly rejected by the world's leading authority
on climate science, the U.N.'s Intergovernmental Panel
on Climate
Change, which found in its latest (2013) report that «There is high confidence that changes in total solar irradiance have not contributed to the increase in global mean surface temperature over the period 1986 to 2008, based on direct satellite measurements of total solar irradiance.&
Change, which found
in its latest (2013) report that «There is high confidence that
changes in total
solar irradiance have not contributed to the increase
in global mean surface temperature over the period 1986 to 2008, based
on direct satellite measurements of total
solar irradiance.»
Jo's scientific interests include radiative transfer
in the atmosphere, climate modelling, radiative forcing of climate
change and the influence of
solar irradiance variability
on climate.
Amplification of the direct
solar forcing is conceivable, e.g., through effects
on ozone or atmospheric condensation nuclei, but empirical data place a factor of two upper limit
on the amplification, with the most likely forcing
in the range 100 — 120 % of the directly measured
solar irradiance change [64].
Critics of this result might argue that the
solar forcing
in these experiments is only based
on the estimated
change in total
irradiance, which might be an underestimate, or that does not include potential indirect amplifying effects (via an ozone response to UV
changes, or galactic cosmic rays affecting clouds).
-LSB-...] This is what the IPCC (the world's most authoritative body
on climate
change) had to say
on solar forcing
in its most recent report «Continuous monitoring of total
solar irradiance now covers the last 28 years.
Excuse the dumb question but why are we wasting our research time
on CO2 emissions rather than the cause of
changes in solar irradiance?
I'm not the most qualified to make a judgment
on their scientific work, but the two authors seem eager to attribute those measurments to an increase of
solar irradiance since 1980, though no serious discussion about the other possible mechanisms (like atmospheric
changes) is made
in the paper.
The
change in total
solar irradiance over recent 11 - year sunspot cycles amounts to < 0.1 %, but greater
changes at ultraviolet wavelengths may have substantial impacts
on stratospheric ozone concentrations, thereby altering both stratospheric and tropospheric circulation patterns... This model prediction is supported by paleoclimatic proxy reconstructions over the past millennium.
The use of even more recently computer - reconstructed total
solar irradiance data (whatever have large uncertainties) for the period prior to 1976 would not
change any of the conclusions
in my paper, where quantitative analyses were emphasized
on the influences of humans and the Sun
on global surface temperature after 1970 when direct measurements became available.
In their evangelism to prove CO2 as the main climate driver, I have no doubt that the IPCC will continue to minimise the importance of Total
Solar Irradiance (TSI)
on climate
change.
Global
solar irradiance reconstruction [48 — 50] and ice - core based sulfate (SO4) influx
in the Northern Hemisphere [51] from volcanic activity (a); mean annual temperature (MAT) reconstructions for the Northern Hemisphere [52], North America [29], and the American Southwest * expressed as anomalies based
on 1961 — 1990 temperature averages (b);
changes in ENSO - related variability based
on El Junco diatom record [41], oxygen isotopes records from Palmyra [42], and the unified ENSO proxy [UEP; 23](c);
changes in PDSI variability for the American Southwest (d), and
changes in winter precipitation variability as simulated by CESM model ensembles 2 to 5 [43].
Considering how deep the
solar minimum was
in 2008 - 2009, and how low total
solar irradiance went compared to where it was
in 1998, given that the average global temperature
changes from peak to trough
in a normal
solar cycle from the
changes in TSI can be of the order as high as.2 degrees centigrade, and also given that we were nearer the peak of the
solar cycle
in 1998 than we were
in the 2009 - 2010 El Nino, I should think that it is more than reasonable to suspect that the difference
in impact of the TSI
on global between 1998's and 2009 - 2010 is easily
on the order of.1 C, or roughly ten times your.01 C figure.
This assessment is based
on multiple lines of evidence and assumes there will be no major volcanic eruptions or secular
changes in total
solar irradiance.
Although we focus
on a hypothesized CR - cloud connection, we note that it is difficult to separate
changes in the CR flux from accompanying variations
in solar irradiance and the
solar wind, for which numerous causal links to climate have also been proposed, including: the influence of UV spectral
irradiance on stratospheric heating and dynamic stratosphere - troposphere links (Haigh 1996); UV
irradiance and radiative damage to phytoplankton influencing the release of volatile precursor compounds which form sulphate aerosols over ocean environments (Kniveton et al. 2003); an amplification of total
solar irradiance (TSI) variations by the addition of energy
in cloud - free regions enhancing tropospheric circulation features (Meehl et al. 2008; Roy & Haigh 2010); numerous
solar - related influences (including
solar wind inputs) to the properties of the global electric circuit (GEC) and associated microphysical cloud
changes (Tinsley 2008).
http://www.agci.org/docs/lean.pdf «Global (and regional) surface temperature fluctuations
in the past 120 years reflect, as
in the space era, a combination of
solar, volcanic, ENSO, and anthropogenic influences, with relative contributions shown
in Figure 6.22 The adopted
solar brightness
changes in this scenario are based
on a
solar surface flux transport model; although long - term
changes are «50 % larger than the 11 - year
irradiance cycle, they are significantly smaller than the original estimates based
on variations
in Sun - like stars and geomagnetic activity.
So, to my previous post, it looks like AR5 will give a bit more coverage to other sources of
solar forcing beside only direct
solar irradiance — it least
in its chapter covering «radiative forcing» if not
in the chapter
on «understanding and attributing climate
change» (which is being written by a different group).
The effect of these
changes on our temperature record has been noted by some researchers, and, like the
change in solar irradiance, it too appears to be small.
The impact of the
solar cycle
on precipitation
in the model experiments arises from two different mechanisms, the first involving UV
changes, the second total
solar irradiance.