Solar Cycle 24 has started - what will it mean for global temps?

Solar cycle 24 has now apparently started. Because of the delay in the start of this solar cycle and strange happenings on the sun there is speculation that cycle 24 could be weak, while others think it will be strong (25 is predicted to be one of the weakest in centuries). A period of lessened solar activity could, according to Svensmark and others, result in a cooler climate (a result that is by no means assured).

If nothing else, the next several years will be interesting to watch to see if cycle 24 is weak or strong and beyond that, whether cycle 25 will be as weak as anticipated -- and what, if any effect this has on our climate.

We live in interesting times..

PS - I'm proud to say I was involved with launch of the SOHO satellite which has taken some great pics of the sun, as shown on www.solarcycle24.com.

 

I have seen numbers of around 0.2C for the solar contribution to 20th C warming (from Total Solar Irradiance alone). This would be around 1/3 of the global temperature increase. What we don't clearly know (and the IPCC has not attempted to study or quantify) is how the sun might affect climate beyond TSI.

Hobbit - as linked above in the OP, the solar mechanism is not only radiative. Svensmark, Shaviv and others believe cosmic rays could be suppressed by a stronger solar wind from an active sun, which in turn would mitigate low cloud formation and therefore warm the earth. The theory has yet to be proven out to my own full satisfaction but there have been some intriguing analysis and experiments (i.e., the SKY experiment). An international research team will conduct additional experiments at CERN (the CLOUD experiment). So we should know more soon about this effect.

Beyond TSI and CRF, there are also recent observations from the Themis satellite that indicate the sun has other mechanisms for transferring large amounts of energy to the earth, though how/if those mechanisms affect climate appears to still be unexplored.

 

You are comparing apples to oranges. The atmosphere of Venus is 96.5% CO2. Earth's atmosphere is currently far less than 1% CO2 (about 0.038% CO2 now, up from about 0.028% CO2 in pre-industrial times). So I don't see any real evidence that "we'll be cooking at 120 or 140". LOL.

However, a small % change in TSI (or other solar forcings) could be a very significant factor in climate change, as noted in the NASA study quoted below:

"TSI interaction with the Earth's atmosphere, oceans and landmasses is the biggest factor determining our climate."

"Historical records of solar activity indicate that solar radiation has been increasing since the late 19th century. If a trend, comparable to the one found in this study, persisted throughout the 20th century, it would have provided a significant component of the global warming the Intergovernmental Panel on Climate Change reports to have occurred over the past 100 years."

My point is that the sun is likely a significant climate driver through TSI alone -- and other effects beyond TSI are now being demonstrated experimentally and may very well show solar effects to be the dominant factor driving observed temperature increases of the 20th C.

 

Looks like the domain is available, if you want to buy it!

 

Apparently some pretty smart folks at NASA think it could be more than "mouse nuts". Anyway, it is not the variability in TSI relative to seasonal variability that is important. It is longer term trend in TSI (and other solar factors) that would matter relative to global climate change.

I'm not sure where you and Alric are going with seasonality...

 

I think it will be hard to isolate one cause from another - natural or otherwise - although certainly a decline in global temperatures is inconsistent with AGW so one would have to ask what was causing the change (and if it caused a decline could the same mechanism cause / explain some amount of increase as well).

 

You are apparently choosing to ignore the referenced NASA study, which concludes nothing of the sort:

"...small variations, like the one found in this study, if sustained over many decades, could have significant climate effects."

The study goes on to imply that indeed, these sort of changes are evident in the historical record:

"Historical records of solar activity indicate that solar radiation has been increasing since the late 19th century."

Ergo, these changes that you characterize as "irrelevant", NASA indicates could very well be "significant". And again, this is only considering TSI, not other solar effects.

See link.

 

Perhaps, perhaps not:

http://www.nature.com/nature/journal/v431/n7012/full/nature02995.html#B1

According to our reconstruction, the level of solar activity during the past 70 years is exceptional, and the previous period of equally high activity occurred more than 8,000 years ago. We find that during the past 11,400 years the Sun spent only of the order of 10% of the time at a similarly high level of magnetic activity and almost all of the earlier high-activity periods were shorter than the present episode.
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http://www.sciencemag.org/cgi/content/abstract/308/5723/847

Newly available surface observations from 1990 to the present, primarily from the Northern Hemisphere, show that the dimming did not persist into the 1990s. Instead, a widespread brightening has been observed since the late 1980s. This reversal is reconcilable with changes in cloudiness and atmospheric transmission and may substantially affect surface climate, the hydrological cycle, glaciers, and ecosystems
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http://www.spacecenter.dk/publications/scientific-report-series/Scient_No._3.pdf

By Lockwood and Frohlich’s own data, solar magnetic
activity is still high compared with 100 years ago. As
to when the recent easing of activity began, counts of
cosmic-ray muons at low altitudes were historically low
when the muon record-keeping ended in the early 1990s
(ref. [7]). That implies an increase in relevant solar mag-
netic activity continuing till that time.

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So it seems that there is still a lot of open scientific debate as to the role of the sun via TSI and other mechanisms. As I mentioned in the original posting, the next few years should be telling as the science evolves, more observations and experiments are conducted, and the future changes in solar activity are evaluated.