Obsessing about tiny percentages of trace gases in the atmosphere may be a popular sport in some quarters these days, but it’s an unproductive one.

Political and corporate leaders gathered for the climate week in New York City have urged significant action to fight global warming, writes Dr. Shaviv in the Epoch Times.

But, given the high costs of the suggested solutions, could it be that the suggested cure is worse than the disease?

As a liberal who grew up in a solar house, I have always been energy-conscious and inclined toward activist solutions to environmental issues.

I was therefore extremely surprised when my research as an astrophysicist led me to the conclusion that climate change is more complicated than we are led to believe.

The disease is much more benign, and a simple palliative solution lies in front of our eyes.

To begin with, the story we hear in the media, that most 20th-century warming is anthropogenic, that the climate is very sensitive to changes in CO2, and that future warming will, therefore, be large and will happen very soon, simply isn’t supported by any direct evidence, only a shaky line of circular reasoning.

We “know” that humans must have caused some warming, we see warming, we don’t know of anything else that could have caused the warming, so it adds up.

However, there is no calculation based on first principles that leads to a large warming by CO2—none. Mind you, the Intergovernmental Panel on Climate Change (IPCC) reports state that doubling CO2 will increase the temperatures by anywhere from 1.5 degrees to 4.5 degrees C, a huge range of uncertainty that dates back to the Charney committee from 1979.

In fact, there is no evidence on any time scale showing that CO2 variations or other changes to the energy budget cause large temperature variations.

There is, however, evidence to the contrary. Tenfold variations in CO2 over the past half-billion years have no correlation whatsoever with temperature; likewise, the climate response to large volcanic eruptions such as Krakatoa.

Both examples lead to the inescapable upper limit of 1.5 degrees C per CO2 doubling—much more modest than the sensitive IPCC climate models predict.

However, the large sensitivity of the latter is required in order to explain 20th-century warming, or so it is erroneously thought.

In 2008, I showed, using various data sets that span as much as a century, that the amount of heat going into the oceans, in sync with the 11-year solar cycle, is an order of magnitude larger than the relatively small effect expected simply from changes in the total solar output. Namely, solar activity variations translate into large changes in the so-called radiative forcing on the climate.

Since solar activity significantly increased over the 20th century, a significant fraction of the warming should be then attributed to the sun, and because the overall change in the radiative forcing due to CO2 and solar activity is much larger, climate sensitivity should be on the low side (about 1 to 1.5 degrees C per CO2 doubling).

In the decade following the publication of the above, not only was the paper uncontested, more data, this time from satellites, confirmed the large variations associated with solar activity.

In light of this hard data, it should be evident by now that a large part of the warming isn’t human, and that future warming from any given emission scenario will be much smaller.

Continued here.
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Professor Nir Shaviv @nshaviv is the chairman of the Racah Institute of Physics at the Hebrew University of Jerusalem.

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September 27, 2019 at 03:31AM