was there a (global) medieval warm period?

was there a (global) medieval warm period?

From co2science.org:

Was there really a global Medieval Warm Period? The IPCC used to acknowledge there was; but they have long since changed their view on the subject. Mounting evidence, however, suggests they were wrong to do so; and in this summary, both old and new important data from Northern Europe that support their original belief are described and discussed.

As for what was learned from this monumental effort, the four researchers say that their new temperature history “provides evidence for substantial warmth during Roman and Medieval times, larger in extent and longer in duration than 20th century warmth.” And it would thus appear to be the case that as ever more data-inclusive and carefully-analyzed studies of palaeo-temperature proxies are conducted, it is becoming ever more evident that there has not been anything unusualunnatural or unprecedented about either the rate of warming or the level of warmth achievedduring the 20th century throughout the whole of Northern Europe, which further suggests that there is likely no real-world empirical evidence for CO2-induced warming anywhere else on the planet either, which suggestion is pretty much verified by similar studies that have been conducted on other continents.

i wrote this (but not that)

It’s occurred to me that almost nothing published on this blog for a very long time is original; that is, what appears here is mostly filched from other blogs or sources. The vast majority of it concerns climate science and global warming. I am not, nor have I ever been, a climate scientist. What I’ve chosen to reproduce is simply a reflection of interest, not expertise. I’ve attempted to make clear that these entries are not mine, not original, but because I’m not really good at this blog thing it sometimes seems as though the writer were me. 

This is not the case!

For other WordPress blogs such as WUWT and Climate Etc. it is usually clear who the author is. But for other sources there’s simply a link to the original material, typically without a byline. This is a combination of ineptitude and laziness. The latter invariably produces the former. I’m working on it. I really am.

hindcasting with the solar model

hindcasting with the solar model

 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!

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.)

new solar theory predicts imminent global cooling

new solar theory predicts imminent global cooling

 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!

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.)

how not to calculate temperatures, pt. 3

how not to calculate temperatures, pt. 3

My disagreement with Steven Goddard has focused on his methodology. His approach is quite simple: he just averages all the temperatures by year for each station, and then averages all the annual means together for all stations in each year.

I’ve been critical of this approach because I’ve argued that it can result in climatology-related biases when the composition of the station network changes. For example, if the decline in reporting stations post-1990 resulted in fewer stations from lower-latitude areas, it would introduce a cooling bias into the resulting temperature record that is unrelated to actual changing temperatures.