We can see that the decadal regression from the trough of the La Nina following the 1998 super El Nino to the peak of the 2010 El nino is negative in southern hemisphere sea surface temperature. Eyballing the data, you would have thought that it would be a positive warming slope. It isn’t. I’m sure you’ll agree that this tells us something about the underlying trend since the start of the C21st.
This is in contrast to the effect of the El Nino Southern Oscillation (ENSO) during the warming period from the mid ’70’s to the turn of the millenium, when El Nino was stronger than La Nina, and the released oceanic heat was resulting in upward step changes in global temperature, identified by Bob Tisdale.
I believe there is an underlying reason for that, and it has less to do with co2 than with the solar contribution to climate change. In a nutshell (heh!), here’s my hypothesis. I hope you find the time to plough through it:
1) Downwelling longwave radiation from greenhouse gases (mostly water vapour, plus co2) can’t penetrate the ocean surface beyond it’s own wavelength. This is well known physics. But the assumption has been that the warming of the surface by this longwave ‘back radiation’ is ‘mixed down’ into the ocean. This is incorrect. When pushed, the physics people supporting the idea of co2 driven warming say that rather then ‘back radiation’ warming the ocean, the effect of additional co2 is to raise the altitude at which the bulk of radiation to space takes place at. This will have the effect of ‘thickening the blanket’ and hence causing the ocean to cool at a slower rate than the rate energy from the sun enters it, causing warming. However, I’ve done the calcs, and the extra height comes to about 150-200m. This isn’t going to make a big enough difference to account for the amount that the ocean warmed from 1980 to 2003.
2) According to data gathered from weather satellites, and measurements of how much of the sunlight hitting Earth gets reflected onto the moon, cloud cover, particularly in the tropics, reduced from 1980 to 1998, and then started increasing again. This allowed more sunlight to get to the ocean (and land) surfaces. Unlike ‘back radiation’ from greenhouse gases, the radiative energies in sunshine penetrate deep into the ocean (up to 150m) and transfer their energy into the seawater. At those depths, wave action, internal currents and tidal flows mix the energy well down into the briny, creating a relatively linear dropoff in temperature from the near surface waters down to the thermocline, between 35m in the tropics, down to 1000m in the higher latitudes. it is this increase in ocean temperature which has caused around half the sea level rise since 1980, due to thermal expansion. The surface temperature of the ocean (70% of Earth’s surface) has risen in proportion to the increased ocean heat content (OHC) in the upper 700m, maybe deeper.
3) The surface of the ocean is on average several degrees warmer than the near surface atmosphere. On average, a net amount of about 65 Watts of energy per square meter is being transferred from the ocean to the atmosphere. The sea surface temperature (SST) thus drives the atmospheric temperature, notwithstanding the relatively small amount of solar radiation absorbed directly by the water vapour and co2. The dominance of the ocean is easily demonstrated by comparing time series of SST and near surface air temperature. The changes in air temperature lag behind changes in SST by several months globally. The ocean contains as much energy in the top two meters as the entire atmosphere above it. This is because the specific heat capacity of water is much, MUCH higher than air. The ocean drives the atmosphere, the tail does not wag the dog.
4) The big uncertainty in climate science is the overall feedback from clouds. High cloud holds heat in at night and makes things warmer. Low cloud blocks sunlight out and makes things colder during the day. Proponents of the anthropogenic global warming hypothesis (AGW) are convinced the overall cloud feedback is positive, and that warmer temperatures mean more evaporation and clouds, trapping heat in – a positive feedback. This is the only way they can get the co2 driven model to work. Co2 on its own isn’t enough, there has to be a positive feedback from water vapour and clouds. Empirical work done by renegade climate scientists such as Dr Roy Spencer and Professor Dick Lindzen empirically find the opposite from satellite data – that cloud feedback is negative, and predominantly cools the Earth down by reflecting sunlight out. Logically, if cloud and water vapour feedback was strongly positive, the Earth’s climate system would be inherently unstable, and the oceans would have boiled 550 million years ago when co2 levels were twenty times higher than now.
5) The AGW proponents say the Sun can’t be responsible for late C20th global warming because the amplitude of the solar cycles has been diminishing since the late 1950’s. There are several problems with this view. Firstly, although the peaks of the solar cycles have been getting lower, the cycles were shorter than average (around 10 years rather than the 11 year average) and the upramps and downramps were steep, and the minima between them brief. This means the average sunspot number over the period about 70 was well above the longterm average of around 40. What I have discovered, is that by making empirical comparisons between SST and the sunspot number (SSN), we find that there is a consistent relationship between the sunspot number and ocean surface temperature when the effects of the oceanic oscillations are accounted for. This means two things: Firstly, there is a relationship between solar activity levels and cloud cover, since small changes in cloud cover make a much bigger difference to the amount of sunlight hitting the ocean than solar variation does. Secondly, there must be a level of solar activity, as indicated by the sunspot number, at which the ocean neither cools nor warms. I have empirically determined this to be around the same value as the long term average sunspot number, about 40SSN. Another problem with the ‘solar cycles diminishing since the ’50’s argument is that Dr Leif Svalgaard (NASA) has used solar magnetic records (derived from geomagnetic records) to determine that Waldmeier, who was in charge of counting the sunspots from 1945 until the mid ’80’s was overcounting by around 20%. Correcting this flattens the previously apparent drop in solar activity a lot.
6) Recently, some experiments have been done at Aarhus in Denmark, and at CERN in Switzerland, which support Henrik Svensmark’s hypothesis that solar activity levels affects the number of cosmic rays getting into Earth’s lower atmosphere and seeding clouds. More active sun, stronger solar wind, less cosmic rays reaching Earth. I have discovered that there is a close correlation between solar activity levels and the specific humidity level up near the tropopause. This will have a bigger effect on the altitude at which radiation of heat to space from Earth occurs at than changes of the atmospheric concentration of co2 from 0.027% to 0.039% will. High altitude specific humidity has been falling since the late 50’s in proportion to the drop in the peak amplitude of the solar cycles. Hungarian physicist Ferenc Miscolzci has determined that the overall optical depth of the atmosphere has stayed pretty much constant, and so the reduction in specific humidity at higher altitude has been matched by an increase at lower altitudes – more lower cloud now the sun has gone quiet. All this means that the solar signal is amplified by terrestrial mechanisms, and indeed this has been shown empirically by Professor Nir Shaviv, who used the oceans as a calorimeter to determine the size of this amplification. However, this amplification is masked in the surface temperature record because of the phasing of ENSO, El Nino’s build during solar cycles and release their energy into the atmosphere when the sun is at minimum, La Nina’s often occur near solar maximum. There has been a big El Nino following solar minimum for the last 5 cycles at least. This anti=phase masking has helped lead to the facile (and incorrect) conclusion that the Sun’s variation doesn’t affect climate much.
7) All the foregoing leads me to two principal conclusions:
c1) Late C20th Global warming was caused predominantly by the Sun, not human emitted co2.
c2) It’s going to get colder, since the sun entered a long minimum in 2005 and shows no signs of getting lively again yet. However, the oceans will continue to kick out heat into the atmosphere for quite a while yet, because a lot of additional heat was stored in them while the sun was more active than average in the latter half of the C20th. This will happen in the form of El Nino’s such as the one we had last year, but rather than the El Nino’s causing an upward step change in global temperature which remains after the El Nino’s have finished, as happened in the 1975-2003 period while the sun was more active than average, they will be followed by La Nina’s which take the global temperature lower, as ocean heat content diminishes.
To test my hypothesis, I’ll make the following prediction:
The current small recovery in temperature following La Nina will be short lived, and global surface temperature will fall again, dropping to below January 2008 levels sometime in the next 6-10 months. This is risky, because ocean dynamics are poorly understood, and no-one knows how much or how fast the accumulated heat in them will be released. So, we will see. If the prediction fails, it isn’t a fatal blow to my hypothesis, but a rethink on temperature stratification in the deep will be in order. Another risk is that a couple of big volcanic eruptions going stratospheric might affect short term temperatures too. Volcanos and Earthquakes are more frequent at times of solar minimum, as we’ll see in another post.