Solar Cycle 24 peaked? The experimentum crucis begins.

The WSO Polar field strengths – early indicators of solar maximums and minimums – have dived towards zero recently, indicating that its all down from here for solar cycle 24.

Polar field reversals can occur within a year of sunspot maximum, but cycle 24 has been so insipid, it would not be surprising if the maximum sunspot number fails to reach the NOAA predicted peak of 90 spots per month, and get no higher than the current 60 spots per month.

The peak in solar intensity was predicted for early 2013, so this would be early, and may be another indication that we are in for a long period of subdued solar cycles.

A prolonged decline in solar output will provide the first crucial experiment to distinguish the accumulation theory of solar driven temperature change, and the AGW theory of CO2 driven temperature change. The accumulation theory predicts global temperature will decline as solar activity falls below its long-term average of around 50 sunspots per month. The AGW theory predicts that temperature will continue to increase as CO2 increases, with little effect from the solar cycle.

An experimentum crucis is considered necessary for a particular hypothesis or theory to be considered an established part of the body of scientific knowledge. A given theory, such as AGW, while in accordance with known data but has not yet produced a critical experiment is typically considered unworthy of full scientific confidence.

Prior to this moment, BOTH solar intensity was generally above its long term average, AND greenhouse gases were increasing. BOTH of these factors could explain generally rising global temperature in the last 50 years. However, now that one factor, solar intensity, is starting to decline and the other, CO2, continues to increase, their effects are in opposition, and the causative factor will become decisive.

For more information see WUWT’s Solar Reference page.