Paper in Press
JOURNAL OF GEOPHYSICAL RESEARCH, doi:10.1029/2011JD017013
What influence will future solar activity changes over the 21st century have on projected global near surface temperature changes?
- Past solar activity is used to estimate future changes in total solar irradiance
- The impact on future global temperatures is estimated with a climate model
- The Sun's influence is much smaller than future anthropogenic warming
During the 20th century solar activity increased in magnitude to a so called `grand maximum'. It is probable that this high level of solar activity is at or near its end. It is of great interest whether any future reduction in solar activity could have a significant impact on climate that could partially offset the projected anthropogenic warming. Observations and reconstructions of solar activity over the last 9000 years are used as a constraint on possible future variations to produce probability distributions of total solar irradiance over the next 100 years. Using this information, with a simple climate model, we present results of the potential implications for future projections of climate on decadal to multi-decadal timescales. Using one of the most recent reconstructions of historic total solar irradiance, the likely reduction in the warming by 2100 is found to be between 0.06 and 0.1K, a very small fraction of the projected anthropogenic warming. However if past total solar irradiance variations are larger and climate models substantially underestimate the response to solar variations then there is a potential for a reduction in solar activity to mitigate a small proportion of the future warming, a scenario we cannot totally rule out. While the Sun is not expected to provide substantial delays in the time to reach critical temperature thresholds, any small delays it might provide are likely to be greater for lower anthropogenic emissions scenarios than for higher emissions scenarios.
Received 12 October 2011; accepted 6 January 2012.
Citation: (2012), What influence will future solar activity changes over the 21st century have on projected global near surface temperature changes?, J. Geophys. Res., doi:10.1029/2011JD017013, in press.