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Global temperatures would have continued to rise rather than level off in the late 1990s without the current ongoing reduction in solar activity, according to a new paper by a Danish climate scientist.
The recent decline in solar activity has caused the so called global warming pause – the recent flattening in the rise of global surface temperatures that was seen in the second half of the twentieth century - and thus disguises an underlying warming trend in the real climate, according to Peter Stauning of the Danish Meteorological Institute, Copenhagen, Denmark. Stauning presents his results in a paper published this month in the open access journal Atmospheric and Climate Sciences.
Solar activity is at its lowest for around 100 years, according to scientists who study the sun (see here), and is likely to remain so for some time. But Stauning's conclusion that the sun is influencing the current changes in the climate runs counter to the prevailing view among climate scientists that the influence of the sun is not significant as set out in a recent paper (see our report here).
“If solar activity starts increasing then the global temperatures may rise even steeper than that seen over the past three decades,” he warns.
Stauning avoids predicting how long the current pause will last stating that his purpose “is not to predict future temperatures but to disclose the effects of the declining solar activity”. His results are based on the HadCRUT-4gl dataset maintained by the UK Meteorological Office and the University of East Anglia's Climate Research Unit but he states that similar results can be obtained using other global temperature series data.
“The development in the global temperatures corrected for the contributions from solar activity displays a steady rise with no indication of the levelling-off of the temperature rise after year 2000 that is seen in the original observed... temperature data,” writes Stauning.
The conclusion of the paper reads: “The decaying solar activity makes the recently recorded global temperatures flatten out and thus disguises the real climate development. With a steady level of cycle-average solar activity the global temperatures would have shown a steady rise from 1980 to present (2013) in agreement with the increasing atmospheric concentrations of green-house gasses, primarily carbon dioxide and methane, and not the levelling-off actually observed since 2001. The solar activity is now at the lowest level seen in the past 100 years and could not go much lower. Thus, the observed global temperatures may soon resume the steady rise observed from around 1980 to 2001. If solar activity starts increasing then the global temperatures may rise even steeper than that seen over the past three decades.”
The question whether human activities seriously affect climate is asked with increasing voice these days. Quite understandable since the climate appears to be out of control with the significant global temperature increases already seen during the last three decades and with still heavier temperature increases to come in the future according to prognoses, among others, in the recent comprehensive IPCC reports. However, the most recent climate data, show global temperature development levelling off or even turning negative since 2001 in contrast to the anticipated course related to the steady increases in the concentration in the atmosphere of green-house gasses, primarily carbon dioxide and methane. The purpose of this communication is to demonstrate that the reduced rate in the global temperature rise complies with expectations related to the decaying level of solar activity according to the relation published in an earlier analysis. Without the reduction in the solar activity-related contributions the global temperatures would have increased steadily from 1980 to present.
Reduced Solar Activity Disguises Global Temperature Rise, by P. Stauning published in Atmospheric and Climate Sciences, Vol. 4 No. 1, 2014, pp. 60-63. doi: 10.4236/acs.2014.41008.
Read the abstract and get the open access paper here.
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