What is the time lag between a change in solar radiation received or retained and a climatic effect?

Question

Suppose that the earth received a constant solar flux for 1000 years (to establish an equilibrium starting condition) and then the solar flux increased by 3 W/m^2 and remained at that value for the next 1000 years. How long would it take for the change to be noticable and how long would it take for a new equilibrium to become established? Should the same time constant apply to both AGW and solar activity theories?

Answer 1

http://www.eia.doe.gov/oiaf/1605/ggccebr...

You and I both know they can't factor in CO2 longevity that theory is still being tossed around.They do have a rough guess but not to the extent you suggest.

Answer 2

Incident solar radiation takes effect immediately, but the effect would need to continue untill the change in temperature was large enough to measure and be statistically significant.  If you just consider radiation and convection a 3W/m2 could result in a change of half a degree C of average temperature, but as walmists rely on positive feedbacks to make their predictions, a walmist would claim that the increase will be more than 2 degrees.  

Solar radiation does vary by around 1 W/m2 over an 11 year cycle (equilavent to a 0.2 W/m2 forcing), but the effect of this is not significant enough that you can see it by looking at the earths temperature graph.  Presumably the temperature is less sensitive to increased radiation than the walmists claim or if there are positive feedbacks, they take a long time to manifest or maybe the feedbacks are net negative.  

Obviously you need more than 1 watt over 5.5 years to be able to detect a change.  

The IPCC considers that it takes several centuries to achieve complete equilibrium after a change in climate forcing.

Answer 3

There are several time lags, each with its own effects. The atmosphere warms rapidly, so the time lag there is several (6-8) months. The upper ocean takes longer, 3-5 years. The deeper ocean even longer, on the order of ~17 years. The longer the time lag, the greater climate sensitivity.

Long-lived greenhouse gases stay in the air for decades to centuries, so they are associated with the longest of these time lags.

Answer 4

wow that might have something to do with the 1000 yr thing in the bible , i have to read it again. but wow your smart. i think thats genious, you have a clear picture with ex. of science. could someone come up with the visual and have no way scientifically to explain. child like description will do. but i could garentee that we all would like to know what the h**l your talking about.? now that s a queation.

Answer 5

The time lag between a change in solar radiation received or retained and a climatic effect: 2 years.

"Temperature tendency associated with the solar cycle, because of the Earth’s thermal inertia, has its minimum delayed by almost a quarter cycle, i.e., about two years."

http://www.columbia.edu/~jeh1/mailings/2...

Should the same time constant apply to both AGW and solar activity theories?

No.  The effects of anthropogenic emissions are too long-lived: "The fraction of CO2 remaining in the air, after emission by fossil fuel burning, declines rapidly at first, but 1/3 remains in the air after a century and 1/5 after a millennium" (Atmos. Chem. Phys. 7, 2287-2312, 2007).

If we continue business as usual with regards to emitting CO2:

- Global and regional warming could more than quadruple after 2100

- Sea level will still be rising at the end of the millennium (3000)

- Ocean pH will fall dramatically for all but the minimum emission scenario

- Business-as-usual could lead to abrupt climate changes

- Abrupt climate changes could occur long after emissions cease

- The ocean carbon sink becomes less effective the more CO2 is emitted

- The land could be a net carbon source on the millennial timescale

"Potential sea level rise on the millennial timescale (excluding the contribution of Antarctica), is 0.5-11.4m in GENIE-1 and 1.0-8.5m in MoBidiC.  Collapse of the West Antarctic Ice Sheet, if it occurs, could add up to 4-6m on the millennial timescale [Oppenheimer and Alley, 2004]"

“…our relatively conservative assumptions, for example regarding climate sensitivity or the exclusion of the Antarctic ice sheets, still produce the result that only by starting to reduce CO2 emissions in the very near future, and continuing to reduce them such that they are zero by year 2200, can we avoid dangerous climate change on the millennial timescale.”

http://www.tyndall.ac.uk/research/theme1...

Answer 6

Given that 3 W/m^2 is nearly twice the estimated excess radiative forcing (anthropogenic and natural) we're currently experiencing (relative to preindustrial era, 1750), one would expect the change would be noticeable within a 10 - 20 year period.  That should be sufficient time to smooth out short-term weather disruptions and annual (e.g. el Nino) type factors.

As far as reaching the new equilibrium, that's beyond me.