There is news on the web saying that there will be Mini Ice Age in couple of decades.
The question is: Will this Mini Ice Age take away all the excessive heat and prevent Global Warming?
I'm going to try to answer this, though it's actually a very hard question depending on how close you look at it.
Lets start with the American Physical Society's statement on climate change - which, they've made an effort to balance out following their 2007 statement of "evidence is incontrovertible" that got some members upset and lead to a handful of high profile resignations. More on that here
This is their more balanced statement.
The relationships between the atmospheric concentration of greenhouse gases and their radiative effects are well quantified. Forcing from the long-lived greenhouse gases: carbon dioxide, methane, and nitrous oxide, is presently about 2.5 Watts per meter squared (W/m2). Of this total, 1.6 W/m2 is from carbon dioxide alone. The total anthropogenic forcing is uncertain, particularly because the magnitude of the negative forcing associated with sulfate aerosols is unclear. While changes in solar irradiance may have affected global climate in the last century, a 0.15% change irradiance, the order of estimated changes, results in only a 0.36 W/m2 forcing.
and, numbers vary, but this seemed a pretty fair article on Solar Irradiance: http://earthobservatory.nasa.gov/Features/SORCE/sorce_03.php
The number of sunspots visible from the Earth not only changes from day to day, but also in cycles that can last from decades to centuries to millennia. The most well-known and well-analyzed of these cycles is the 11-year sunspot cycle. Over the course of 11 years, the yearly average number of sunspots and faculae slowly increases and then return to normal levels before rising again for the subsequent cycle. The change in the Sun’s yearly average total irradiance during an 11-year cycle is on the order of 0.1 percent or 1.4 watts per square meter.
So, 1.6 watts per square meter from Co2 (2.5 watts total) and (up to) 1.4 watts per square meter low to peak solar irradiance, but there's a problem with that 1.4 number. It's low to high, meaning low to average is 0.7 watts per square meter and that's how we should measure assuming the sun enters a grand minimum, we should measure against the average, so the real number is 0.7 watts per square meter drop - assuming the study is right and the sun does enter a new Maunder Minimum.
Skeptical Science posts a similar number:
The variation in their chart appears to be similar to the 0.7 variation we should expect from the NASA article, average to low range.
There's also the, all but guarantee that CO2 will continue to rise, at least, for several more years, so the APS estimate is likely to go up. Also, the APS number doesn't include feedback mechanisms - and they say as much in the article linked above:
The largest source of uncertainty lies in determining the magnitude of climate feedbacks. For example, an increase in trapped radiation and the associated warming is expected to increase the level of water vapor in the atmosphere, which would tend to further enhance the greenhouse effect ó a positive feedback. An example of a negative feedback would be an increase in clouds that reflected more sunlight back into space. The actual feedback from changes in clouds is uncertain since they also act to trap outgoing infrared radiation.
Now, the positive feedback from water vapor is a given and the negative feedback from clouds is more uncertain, so I think the APS article is a little bit more friendly to the skeptics than the actual science (IMHO). Clouds reflect sunlight, but clouds also trap heat at night. The total cloud effect is, well, a little more cloudy than APS' one line suggests.
Skeptical Science has an article on cloud feedback here: http://www.skepticalscience.com/clouds-negative-feedback.htm
So, where does that leave us:
Well, first, the study that the sun is going to enter a grand minimum in the next few decades needs to be verified, lets start there. A whole bunch of bad science has been published by those trying to disprove, discredit or cast doubt on climate change - so skeptisism of new studies first, especially on this topic, but, lets say they're right - which was the original question. Would that be sufficient to stop man made global warming?
No. I think it's pretty likely it would be insufficient. 0.7 is less than 2.5. But, if they're right, it's still kind of good news, cause it would soften the blow - and that's a good thing. I hope they are right. But the sun's maximums and minimums have a pretty small effect on climate change. Maybe a degree here or there. Man made climate change should be 2 degrees by the end of the century, and perhaps more if left unaddressed in centuries that follow.
As Steve Emmerson points out, the effect of the Maunder Minimum isn't 100% accepted as the sole cause of the Mini ice age. There's still some unknowns, but I feel, with pretty high confidence, that the sun entering a new grand minimum would be insufficient to stop the warming, but it might slow it down, a little.
Too long? I can try to clean it up a bit later.
No, solar activity will not help offset anthropogenic warming in any significant way.
Recent research says a grand solar minimum would cause no more than 0.3C cooling over the 21st century [Feulner & Rahmstorf (2010), Jones et al. (2012), Anet et al. (2013)]
But to see the influence of the solar cycle on the earth's climate together with the effect of anthropogenic forcing see @userLTK's chart - it is key. Roughly after 1960 solar activity declines on average while temperature rampantly rises. Why? Atmospheric CO2: [the] Principal Control Knob Governing Earth’s Temperature .
Although solar activity is modulating the earth's temperature the effect is relatively small and for all practical purposes - negligible. Otherwise the past 12,000 years of civilization would have been much tougher to endure.
The "mini ice age" hypothesis is hype (note the lack of references to supporting peer-reviewed literature). For scientific information on its possibility, see this GRL article by Meehl et al. (2013). From the abstract:
A future Maunder Minimum type grand solar minimum, with total solar irradiance reduced by 0.25% over a 50 year period from 2020 to 2070, is imposed in a future climate change scenario experiment (RCP4.5)... After the initial decrease of solar radiation in 2020, globally averaged surface air temperature cools relative to the reference simulation by up to several tenths of a degree Centigrade. By the end of the grand solar minimum in 2070, the warming nearly catches up to the reference simulation. Thus, a future grand solar minimum could slow down but not stop global warming.
The article is open access and can be read without payment or subscription.
Meehl, G. A., J. M. Arblaster, and D. R. Marsh (2013), Could a future “Grand Solar Minimum” like the Maunder Minimum stop global warming?, Geophys. Res. Lett., 40, 1789–1793, doi:10.1002/grl.50361.
According to GW theory, global temperature trends toward an equilibrium depending on CO2 concentration. If we could stabilize concentration at today's levels it would take decades to approach equilibrium.
If we were in the equilibrium state we might have cooler periods due to events like the Pinatubo eruption or a Solar minimum, but then the temperature would return to equilibrium.
If we continue to increase concentrations, these temporary cooling events might appear to counteract warming, but when they are finished, the temperature will trend up ("with a vengeance") to the level corresponding to the higher concentration.