Sentences with phrase «irradiance changes on»

The panel concludes there is very high confidence that the warming is due to human activities, which are likely to have been at least five times greater than the impact of solar irradiance changes on global warming.

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.

Note that the last remark can go either way, as the solar signal can even be more enhanced at the cost of the sensitivity for the greenhouse signal... And from Hansen ea.: «Solar irradiance change has a strong spectral dependence [Lean, 2000], and resulting climate changes may include indirect effects of induced ozone change [RFCR; Haigh, 1999; Shindell et al., 1999a] and conceivably even cosmic ray effects on clouds [Dickinson, 1975].

[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.»

Let's set the stage by noting that, as a significant competitor to anthropogenic greenhouse forcing of recent climate change, the direct radiative forcing by solar irradiance variations is dead on arrival.

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].

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.»

On longer time scales, solar - related effects may play a bigger role, though I have yet to be persuaded that the observations imply a stronger effect than you can get just with irradiance / ozone changes.

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.

On the other hand, chromospheric indices and hence solar UV irradiance do not exhibit a similar change.

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.

Further, our temperature reconstructions, within age uncertainty, can be well correlated with solar irradiance changes, suggesting a possible link between solar forcing and natural climate variability, at least on the northern Tibetan Plateau.»

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.

These changes can be measured [the Total Solar Irradiance = TSI], but the changes are much too small to have any influence on our climate.

I have quoted Palle above on the small contribution of solar irradiance changes to climate change.

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].

Of course, the same could be said for global temperature, where a half degree C temperature increase on an absolute Kelvin scale would only be about 0.17 %, so an argument can be made that on a percentage basis, this change in irradiance is about the same order of magnitude as our change in temperature.

Second, their temperature reconstructions were not based exclusively on TSI changes as the sole source of temperature variation, but included associated changes in spectral irradiance that would be expected to amplify TSI effects, changes in UV being one example.

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).

With regard to proxy studies, same basic questions, are these direct or passive correlations, what evidence that tree ring core thickness depends only on temperature (what about precipitation, cloud cover, volcanic activity, sea surface temperatue changes, sea current changes, solar irradiance changes, cloud cover, etc.) How are these variables accounted for when analysis of ice cores is completed, or for that matter when computer models, and / or proxy studies are completed.

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.