National Post (National Edition)
The sun raises the seas
IPCC and others blame CO2 for increases in sea levels, ignoring evidence that shows the sun to be the cause
For many years we have been told that global warming is unprecedented over the past 100 years, that human industrial activity is by far the dominant driver of 20th century climate change, and that nothing else is important.
Years ago, I too accepted this idea. After all, it came from the Intergovernmental Panel on Climate Change (IPCC), which was supposed to summarize the leading consensus on the subject. Having grown up in a solar house, it also naturally fit my environmentfriendly background.
However, a casual question back in 2000, from a colleague while I was doing post-doctoral work at the Canadian Institute for Theoretical Physics at the University of Toronto, led to surprising revelations on climate change. My colleague, an astrophysicist, asked me how cosmic rays from supernovae could affect life on earth, which led me to explore this area of study. I found that the sun’s variability as well as unrelated cosmic ray variations, explain a surprisingly large amount of the observed climate variations, from the 11-year solar cycle to geological time scales. In fact, models including the real effect of the sun also do a much better job in explaining 20th century global warming than those limited to the influence of human carbon dioxide emissions alone.
Most importantly, empirical evidence shows that the sun’s influence on climate is very large, much larger than expected from variations in the Total Solar Irradiance— the only solar forcing that is considered by the IPCC. The full forcing, which is large, can be quantified by studying the sea level as it is linked to heat going into the oceans and therefore the radiative forcings through thermal expansion. This can be seen in the figure, where the tide-gauges-based sea level change rate is seen to vary in sync with the solar cycle, averaging close to 2 mm a year. The amount of heat inferred from this large correlation corresponds to at least six times the forcing of the irradiance alone. However, this empirical evidence and its implications are ignored in models considered by the IPCC, although it explains most of the 2 mm a year increase in sea level that NASA reports.
As an astrophysicist, I see that the scope of solar effects considered by the IPCC is very limited; thus it arrives at wrong conclusions about what causes climate change.
For instance, the increase in solar activity over the 20th century implies that more than half of the warming should be attributed to the sun, not to emissions from human activity.
I have reviewed the IPCC climate models and the evidence shows that their “climate sensitivity,” such as to CO2 variations, is far too high. Models which exclude the real effect of the sun require an artificially high climate sensitivity to explain 20th century warming. This high sensitivity then predicts a high temperature rise for any given scenario over the 21st century.
But models are computer simulations of which the predictive power is limited by large uncertainties in the input physics, such as feedbacks through cloud cover variations. Cloud modelling remains a major challenge and an uncertainty factor in climate modelling.
Instead of the model simulations, if we look at the evidence we see a different story.
A range of empirical evidence points to a low climate sensitivity to carbon dioxide (CO2), meaning that CO2 has limited effect on warming. In particular, large CO2 variations over geological time scales give rise to no apparent temperature varia- tions and large volcanic eruptions cool the planet by only 0.1°C on average (compared with 0.3-0.5 predicted by models employed by the IPCC).
And of course there is the “hiatus.” The IPCC concluded in Chapter 9 of its September 2013 Working Group I report that there had been a 15-year hiatus in Global Surface Meant Temperatures (GSMT) that had not been predicted by a single computer model.
Currently, satellite data show that the hiatus has continued over 18 years, even though carbon dioxide has risen significantly. This implies that Earth’s temperature increases less (from the influence of CO2) than IPCC predictions, because those were based on a high climate sensitivity ascribed to CO2.
In my research, when the sun’s role is considered, 20th-century warming is much better explained and has a better fit to the observed data while requiring a low climate sensitivity.
The low climate sensitivity implies that typical emission scenarios will result in about a 1°C increase between the present temperature and that which is likely in 2100.
Some aspects of solar activity that affect global climate change are too complex to explain in a short newspaper op-ed. I have a blog called “ScienceBits” where I explain my work in lay terms, including links to the scientific papers supporting those conclusions.
In short, the research work that my colleagues and I carry out shows that the leading mechanism to link solar activity with climate is that of cosmic ray modulation. This is supported by a range of empirical evidence including paleo-climate variations associated with variations in the cosmic ray flux density around the solar system (from spiral arm passages and the motion of the solar system perpendicular to the galactic plane).
There are many good reasons why we should reduce our reliance on fossil fuels, but carbon dioxide emissions is not one of them.
I am optimistic that humanity will switch to alternative energy sources within a few decades once they become cheaper than fossil fuels, which they will. Based on the significant costs and market disruptions caused by extreme carbon reduction policies, it would be best if this transition happen due to innovation and technological advances, without the current large subsidies, most of which are driven by fear of a climate catastrophe. Such irrational behaviour has already led to many negative, unintended consequences for the environment and national economies. Thus, the precautionary principle could have detrimental repercussions.
Based on my “galactic view” of climate change, the good news is we’re not doomed. The “carbon risk” of catastrophic global warming or climate change is low. The sun has a far greater, natural influence on climate than many are willing to admit.
The hiatus has continued over 18 years, even though carbon dioxide has risen significantly