Most of the Recent Warming Could be Natural – Jennifer Marohasy

The author notes that ‘while mainstream climate science is replete with published proxy temperature studies showing that temperatures have cycled up and down over the last 2,000 years – spiking during the Medieval Warm Period and then again recently to about 1980 as shown in Figure 12 – the official IPCC reconstructions (which underpin the Paris Accord) deny such cycles.’

We could add ‘and then says the science is settled’.
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After deconstructing 2,000-year old proxy-temperature series back to their most basic components, and then rebuilding them using the latest big data techniques, John Abbot and I show what global temperatures might have done in the absence of an industrial revolution, writes Jennifer Marohasy.

The results from this novel technique, just published in GeoResJ [1], accord with climate sensitivity estimates from experimental spectroscopy but are at odds with output from General Circulation Models.

According to mainstream climate science, most of the recent global warming is our fault – caused by human emissions of carbon dioxide.

The rational for this is a speculative theory about the absorption and emission of infrared radiation by carbon dioxide that dates back to 1896.

It’s not disputed that carbon dioxide absorbs infrared radiation, what is uncertain is the sensitivity of the climate to increasing atmospheric concentrations. This sensitivity may have been grossly overestimated by Svante Arrhenius more than 120 years ago, with these over-estimations persisting in the computer-simulation models that underpin modern climate science. We just don’t know; in part because the key experiments have never been undertaken.

What I do have are whizz-bang gaming computers that can run artificial neural networks (ANN), which are a form of machine learning: think big data and artificial intelligence. My colleague, Dr John Abbot, has been using this technology for over a decade to forecast the likely direction of particular stock on the share market – for tomorrow.

Since 2011, I’ve been working with him to use this same technology for rainfall forecasting – for the next month and season. And we now have a bunch of papers in international climate science journals on the application of this technique showing its more skilful than the Australian Bureau of Meteorology’s General Circulation Models for forecasting monthly rainfall.

During the past year, we’ve extended this work to build models to forecast what temperatures would have been in the absence of human-emission of carbon dioxide – for the last hundred years.

Continued here.
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[1] The new paper in GeoResJ is available free of charge until 30 September 2017, at this link:
http://ift.tt/2vZnQS3