Watts Up With That?

Source: Mantua, 2000

The essay below has been part of a back and forth email exchange for about a week. Bill has done some yeoman’s work here at coaxing some new information from existing data. Both HadCRUT and GISS data was used for the comparisons to a doubling of CO2, and what I find most interesting is that both Hadley and GISS data come out higher in for a doubling of CO2 than NCDC data, implying that the adjustments to data used in GISS and HadCRUT add something that really isn’t there.

The logarithmic plots of CO2 doubling help demonstrate why CO2 won’t cause a runaway greenhouse effect due to diminished IR returns as CO2 PPM’s increase. This is something many people don’t get to see visualized.

One of the other interesting items is the essay is about the El Nino event in 1878. Bill writes:

The 1877-78 El Nino was the biggest event on record.  The anomaly peaked at +3.4C in Nov, 1877 and by Feb, 1878, global temperatures had spiked to +0.364C or nearly 0.7C above the background temperature trend of the time.

Clearly the oceans ruled the climate, and it appears they still do.

Let’s all give this a good examination, point out weaknesses, and give encouragement for Bill’s work. This is a must read. – Anthony

A guest post by: Bill Illis

People have noted for a long time that the effect of the El Nino Southern Oscillation (ENSO) should be accounted for and adjusted for in analyzing temperature trends.  The same point has been raised for the Atlantic Multidecadal Oscillation (AMO).  Until now, there has not been a robust method of doing so.

This post will outline a simple least squares regression solution to adjusting monthly temperatures for the impact of the ENSO and the AMO.  There is no smoothing of the data, no plugging of the data; this is a simple mathematical calculation.

Some basic points before we continue.

-         The ENSO and the AMO both affect temperatures and, hence, any reconstruction needs to use both ocean temperature indices.  The AMO actually provides a greater impact on temperatures than the ENSO.

-         The ENSO and the AMO impact temperatures directly and continuously on a monthly basis.  Any smoothing of the data or even using annual temperature data just reduces the information which can be extracted.

-         The ENSO’s impact on temperatures is lagged by 3 months while the AMO seems to be more immediate.  This model uses the Nino 3.4 region anomaly since it seems to be the most indicative of the underlying El Nino and La Nina trends.

-         When the ENSO and the AMO impacts are adjusted for, all that is left is the global warming signal and a white noise error.

-         The ENSO and the AMO are capable of explaining almost all of the natural variation in the climate.

-         We can finally answer the question of how much global warming has there been to date and how much has occurred since 1979 for example.  And, yes, there has been global warming but the amount is much less than global warming models predict and the effect even seems to be slowing down since 1979.

-         Unfortunately, there is not currently a good forecast model for the ENSO or AMO so this method will have to focus on current and past temperatures versus providing forecasts for the future.

And now to the good part, here is what the reconstruction looks like for the Hadley Centre’s HadCRUT3 global monthly temperature series going back to 1871 – 1,652 data points. Read the rest of this entry »