To recap — using an optimal Fourier Transform, David Evans discovered a form of notch filter operating between changes in sunlight and temperatures on Earth. This means there must be a delay — probably around 11 years. This not only fitted with the length of the solar dynamo cycle, but also with previous independent work suggesting a lag of ten years or a correlation with the solar activity of the previous cycle. The synopsis then is that solar irradiance (TSI) is a leading indicator of some other effect coming from the Sun after a delay of 11 years or so.

The discovery of this delay is a major clue about the direction of our future climate. The flickers in sunlight run a whole sunspot cycle ahead of some other force from the sun. Knowing that solar irradiance dropped suddenly from 2003 onwards tells us the rough timing of the fall in temperature that’s coming (just add a solar cycle length). What it doesn’t tell us is the amplitude — the size of the fall. That’s where the model may (or may not) tell us what we want to know. That test is coming, and very soon. This is an unusual time in the last 100 years where the forecasts from the CO2 driven models and the solar model diverge sharply. Oh the timing!

Ponder how ambitious this simple model is — the complex GCM’s only aim to predict decadal trends, and have failed to even do that. Here is a smaller simpler model proffering up a prediction which is so much more specific. The Solar Model has not shown skill yet in predictions on such short time-scales, though it hindcasts reasonably well on the turning points and longer scales. It cannot predict ENSO events, and obviously not aerosols, nor volcanoes. But if the notch-delay theory is right, the big drop coming is larger than the short term noise.

As we head to the UNFCCC meeting in Paris 2015 where global bureaucracy beckons, a sharp cooling change appears to be developing and set to hit in the next five years. Yet consortia of five-star politicans are not preparing for climate change, only for global warming. Around the world a billion dollars a day is invested in renewable energy, largely with the hope of changing the weather. Given that 20% of the world does not even have access to electricity, history books may marvel at how screwed priorities were, and how bureaucratized science cost so much more than the price of the grants.

As Bob Carter has been saying for a long time, politicians need to prepare for everything the climate may throw at us — see Climate the Counter Consensus.

Global Cooling is Imminent

Dr David Evans, 27 June 2014, David Evans’ Notch-Delay Solar Theory and Model Home

If the Sun mainly controls the temperature on Earth, a turning point is almost upon us. (In the second part of this series of blog posts we will demonstrate that carbon dioxide is responsible for less than 25% of the global warming of the last six decades, so presumably the Sun is mainly responsible.)

1 Why It’s Going to Cool

The reason for the cooling is the dramatic fall in solar radiation that started around 2004. Here is a graph of solar radiation since 1610, when sunspots were first recorded. The brown line is the solar radiation, and it peaks every 11 years or so because of the sunspot cycle. We put an 11-year smoother through it to give us the red line, which shows the trends in solar radiation.

Figure 1: The recent fall in TSI is the steepest and one of the largest ever recorded (records go back to 1610).

UPDATE: This graph has been updated after the PMOD revisions to TSI in late 2013 or 2014. It makes very little difference. Compare the new graph to the original here.

There have been three big, steep falls in solar radiation in the last 400 years.

The first was in the 1600s. It led to the depths of the Little Ice Age, and the Maunder Minimum. This was the coldest period during the last 400 years. There used to be fairs on the ice in the Thames River in London, because it would freeze over for weeks at a time.

The second fall is around the time of Napoleon and it preceded the second coldest period in the last 400 years, called the Dalton Minimum.

The third fall occurred recently, starting in about 2004. This recent fall is as big as the fall in Napoleon’s time, almost as large as the fall in the 1600s, and it seems to be steeper than either of those falls. But the temperature hasn’t fallen … yet.

2 When

The timing for the cooling is indicated by the delay, which was deduced from the observed notch but has been independently corroborated to varying extents several times in the last decade (see Post III). The delay is most likely 11 years, though definitely between 10 and 20 years.

2004 + 11 = 2015.

Eleven years after 2004 is 2015, suggesting the cooling will start in 2015. However, 11 years is only the average delay, and the physical interpretation of the delay (see Post IV) suggests the delay is actually the length of the solar cycle—which has varied from 8 to 14 years, but averages 11 years. The current solar cycle is a long one, probably running around 13 years:

2004 + 13 = 2017.

So the cooling is most likely to begin in 2017.

The delay could be as much as 20 years, in which case the drop could be as late as 2024. Or it could occur as soon as 2014. An El Nino or La Nina could affect the timing too. At this stage, we don’t know. But by the end of 2018 seems fairly likely.

(Notice that so far we have only applied our physical understanding of the delay, and its implication of a powerful solar influence that is signaled by changes in solar radiation but acts after a period of time equal to the delay.)

3 How Much Cooling

How much cooling and how quickly? For that we turn to the notch-delay solar model, which hindcasts the last 240 years of temperatures reasonably well simply from the total solar irradiance (TSI). This model was developed earlier in this series of blog posts; see here for an overview and links.

The changes in solar radiation are tiny, and have an almost insignificant immediate effect on Earth’s temperatures. However the physical interpretation of the notch and delay (see Post IV) show that these little changes foretell the changes in a newly detected climate influence from the Sun, which we are calling “force X” for now. The effect on temperatures of changes in force X is 10 to 20 times as great as the immediate effect of changes in solar radiation (see Post VI). Force X works by modulating the albedo of the Earth, or the amount of solar radiation reflected straight back out to space without changing the heat of the planet, by clouds and ice and so on. Force X turns the tap that controls how much sunlight pours into the Earth’s climate system. This could be through UV, magnetic field effects, solar wind, or some form of electrical field.

Force X lags TSI by half of a full solar cycle of 22 years, which is to say, by 11 years on average. Therefore the changes in solar radiation over the last 11 years tell us what force X is going to do soon. It’s already baked in the cake; we can see a few years into the future.

Figure 2: Climate model driven only by solar radiation, with no warming due to carbon dioxide. See Post VII for explanation. Predictions shown by dotted lines. This instance of the notch-delay solar model used a constant delay of 10.7 years and shows cooling beginning in 2014.

UPDATE: The predictions have been updated with new TSI data from PMOD revisions in late 2013 or 2014. Again, there is little difference, compared to the original.

If the temperature on Earth is entirely controlled by solar effects, the cooling will return us to the temperature levels of the 1950s or even the 1920s, undoing the last 50 or 100 years of global warming in just a few short years.

The temperature data from land thermometers from 1850 to 1978 may have exaggerated past temperature rises. The solar model here trained on that data so it may be too sensitive, in which case the imminent cooling will not be as large as shown in absolute terms.

At least a small portion of the recent global warming was due to rising carbon dioxide, so the fall will not be as large as shown in Figure 2.

4 Solar versus Carbon Dioxide

Both the carbon dioxide and notch-delay solar theories agree with the warming observed during the 1900s, because carbon dioxide levels and solar radiation levels were both generally rising. So we cannot tell the models apart on recent performance.

However, over the next 10 years the theories strongly diverge. Carbon dioxide levels will continue to rise at much the same rate, so the carbon dioxide models predict warming over the next decade of about 0.2°C, plus up to 0.3°C of previously-committed warming not reflected in the temperature “pause” of the past 15⁺ years. Owing to the fall in solar radiation from around 2004, and making allowance for rising carbon dioxide, the notch-delay solar model predicts cooling of 0.2°C or more.

Figure 3: Comparing the CO₂and solar models. They show general agreement from 1900 to 2000, because carbon dioxide and solar radiation levels were generally rising, but they diverge sharply soon.

5 Theories and Falsifiability

Science is about testable hypotheses. Over the next decade, the changes in temperature will reveal which theory is more correct, the carbon dioxide model or the notch-delay solar model.

Here’s the criterion: A fall of at least 0.1°C (on a 1-year smoothed basis) in global average surface air temperature over the next decade.

If the criterion does not occur: Then the notch-delay solar model is falsified and it should be thrown away.

If the criterion does occur: Then carbon dioxide driven models are falsified, and they should be thrown away. (Note that the carbon dioxide theory predicts only warming over longer periods such as a decade, and we’ve already had a pause in warming for 15⁺ years.)

6 Old Temperatures

The Maunder Minimum from about 1645 to 1715 and the Dalton period from about 1790 to 1830 are generally reckoned to be the two coldest times in the last 400 years.

There was no global thermometer network before 1850, so for a global picture we have to rely on proxy data (ice-cores, pollen, marine sediments, lake sediments, tree-rings, etc.). The most comprehensive study is Christiansen and Ljungqvist’s huge proxy study in 2012, which used 91 proxies scattered around the world. We smoothed it by 25 years in Figure 1 because proxy data is uncertain and hazy.

Even the IPCC thought those two periods were the coldest in the last 400 years, before they went all hockeystick:

Figure 4: From the First Assessment Report of the IPCC, page 202.

Fig 5 (updated) IPCC Second Assessment Report, Fig 3.20 page 175, The SAR WGI first pdf). Decadal summer temperature index for the Northern Hemisphere, from Bradley and Jones (1993), up to 1970-1979. The record is based on the average of 16 proxy summer temperature records from North America, Europe and eastAsia. The smooth line was created using an apporximately 50-year Gaussian filter. Recent instrumental data for Northern Hemisphere summer temperature anomalies (over land and ocean) are also plotted (thick line). The instrumental record is probably biased high in the mid-19th century because of exposures differing from current techniques (eg Parker, 1994b)

UPDATE: We’ve replaced the graph originally posted (copied here) which was sourced via here. Thanks especially to William Connolley for the proof reading and to ThinkingScientist for accurately finding the actual SAR IPCC Graph above. It is entirely incidental to the Solar Model or its predictions, a mere side note here, not included in the main paper or the model, but we always appreciate feedback. The point remains that it has been long accepted that solar minima correspond to cooler temperatures on Earth. — Jo

7 What’s Next

This almost finishes the first part of this series of blog posts. The second part is about finding whether the carbon dioxide or solar model is dominant, from the evidence to date. This develops a method for computing the extent of causation, and finds that rising carbon dioxide levels were responsible for less than 25% of the global warming of the last 60 years.

The next post in this series is of the spreadsheet that contains all the data, code and the model behind the notch-delay solar theory. We have delayed releasing it so as not to preempt the blog posts, and to engender a more focused conversation.

The home page for the entire notch-delay solar theory is here. It includes links to all these blog posts, with summaries.

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