Is the earth ever in equilibrium? Is it chaos or determinism?

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Fantastic!

Schatz (above) writes: "Past climate change actually provides evidence that humans can affect climate now."

Gotta love that circular logic.

The two work together. Determinism has its limitations, but it also has its uses. The problem is to pick the correct model in the circumstances in which you find yourself. Determinism works for many practical purposes. Chaos comes into play when we reach the limits of determinism. These are often to do with very complex, very distant problems to do with the very large, the very small, or large populations. Absolute determinism always had enormous problems. After all, if everything is determined, what is the point of ay of it? It is simply playing out a script. At the same time, we use deterministic prediction all the time in our lives. The human mind traditionally functions in a deterministic universe, even though we often confuse cause and effect, or even get them completely wrong.

I'm not a climatologist. Nor have I ever played one on television. What I am is a minor mathematician, science enthusiast and former computer programmer.

What does any of the above have to do with your question? It means that I know a little about the scientific process of establishing 'proofs' of a particular theory. Is global warming real? Has mankind played a significant role in creating worldwide 'climate change'?

The answer is 'who knows?' The crowd at East Anglia have lost original data. They have fudged the data. They have tweaked the algorithms. [Aside, who knew that Al Gore had rhythm?] They basically hand picked their peers to do the review. None of their models predicted the climate over the last decade or so.

Way back in the IBM 360 era (1970's) I wrote some computer modeling programs. What I learned was that if you fudge data and tweak algorithms you could make the results anything that you wanted them to be. So, I just don't believe them. It certainly isn't 'settled science'. NOTHING in science is 'settled'. Everything is open to new information. Everything is open to new theories.

Speaking of new theories, is it possible that 'el nino' is affected by the volcanic vents on the ocean floors known as 'black smokers'? Since we know so little about them, could they be the cause of warming/cooling of the Pacific Ocean that causes el nino? Could this be the cause of global warming? Has this been included in the East Anglia algorithms?

Again, who knows?

As is often said, "There are three types of lies, 'lies', 'Damn lies' and 'statistics'."

It is probably chaotic. That isn't what he said though. He simply stated what should be undeniable, that ocean currents like the ones he mentioned.

"El Nino, the Pacific Decadal Oscillation, the Atlantic Multi-decadal Oscillation, etc. Recent work suggests that this variability is enough to account for all change in the globally averaged temperature anomaly since the 19th century"

They are possibly enough to account for the fluctuation of temperature by themselves. What part of that is even remotely controversial? None is yet we have the usual suspects denying reality and apparently not even able to understand basic elementary English. They redefine that into something that "climate scientists" don't agree with so they can conveniently ignore what he actually said because it might interfere with their agendas.

Schatz is spot on. Indeed, the observation that past temperature changes were greater than would have been predicted from the orbital cycles that caused them, is part of what alerted the scientific community to the seriousness of what is happening now, and what lies ahead of us under business as usual.

Chaotic systems are entirely deterministic. For some reason, laymen confuse chaos with randomness, which is absolutely wrong.

Anyway, there have been several questions on this article already, and it really contains little of substance.

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"Bob, I don't think so."

--Fantastic. You're still wrong, but I'm glad you have an opinion.

"Are you a layman?"

--I've taken enough courses on DEs and nonlinear dynamics to know that 'deterministic chaos' (also known as 'chaos') isn't meant as an ironic title.

It's good question. Professor Lindzen has made this argument before, but you should know a very large majority of professors and scientists in the world say he is simply wrong. Here is why:

If there's one thing that all sides of the climate debate can agree on, it's that climate has changed naturally in the past. Long before industrial times, the planet underwent many warming and cooling periods. This has led some to conclude that if global temperatures changed naturally in the past, long before SUVs and plasma TVs, nature must be the cause of current global warming. This conclusion is the opposite to what peer reviewed science has found.

Our climate is governed by the following principle: when you add more heat to our climate, global temperatures rise. Conversely, when the climate loses heat, temperatures fall. Say the planet is in positive energy imbalance. More energy is coming in than radiating back out to space. This is known as radiative forcing, the change in net energy flow at the top of the atmosphere. When the Earth experiences positive radiative forcing, our climate accumulates heat and global temperature rises (not monotonically, of course, internal variability will add noise to the signal).

How much does temperature change for a given radiative forcing? This is determined by the planet's climate sensitivity. The more sensitive our climate, the greater the change in temperature. The most common way of describing climate sensitivity is the change in global temperature if CO2 is doubled. What does this mean? The amount of energy absorbed by CO2 can be calculated using line-by-line radiative transfer codes. These results have been experimentally confirmed by satellite and surface measurements. The radiative forcing from a doubling of CO2 is 3.7 Wm-2 (IPCC AR4 Section 2.3.1).

So when we talk about climate sensitivity to doubled CO2, we're talking about the change in global temperatures from a radiative forcing of 3.7 Wm-2. This forcing doesn't necessarily have to come from CO2. It can come from any factor that causes an energy imbalance.

How much does it warm if CO2 is doubled? If we lived in a climate with no feedbacks, global temperatures would rise 1.2°C (Lorius 1990). However, our climate has feedbacks, both positive and negative. The strongest positive feedback is water vapour. As temperature rises, so too does the amount of water vapour in the atmosphere. However, water vapour is a greenhouse gas which causes more warming which leads to more water vapour and so on. There are also negative feedbacks - more water vapour causes more clouds which can have both a cooling and warming effect.

What is the net feedback? Climate sensitivity can be calculated from empirical observations. One needs to find a period where we have temperature records and measurements of the various forcings that drove the climate change. Once you have the change in temperature and radiative forcing, climate sensitivity can be calculated. Figure 1 shows a summary of the peer reviewed studies that have determined climate sensitivity from past periods (Knutti & Hegerl 2008).

There have been many estimates of climate sensitivity based on the instrumental record (eg - the past 150 years). Several studies used the observed surface and ocean warming over the twentieth century and an estimate of the radiative forcing. A variety of methods have been employed - simple or intermediate-complexity models, statistical model or energy balance calculations. Satellite data for the radiation budget has also been analysed to infer climate sensitivity.

Some recent analyses used the well-observed forcing and response to major volcanic eruptions during the twentieth century. A few studies examined palaeoclimate reconstructions from the past millennium or the period around 12,000 years ago when the planet came out of a global ice age (Last Glacial Maximum).

What can we conclude from this? We have a number of independent studies covering a range of periods, studying different aspects of climate and employing various methods of analysis. They all yield a broadly consistent range of climate sensitivity with a most likely value of 3°C for a doubling of CO2.

The combined evidence indicates that the net feedback to radiative forcing is significantly positive. There is no credible line of evidence that yields very high or very low climate sensitivity as a best estimate.

CO2 has caused an accumulation of heat in our climate. The radiative forcing from CO2 is known with high understanding and confirmed by empirical observations. The climate response to this heat build-up is determined by climate sensitivity.

Ironically, when skeptics cite past climate change, they're in fact invoking evidence for strong climate sensitivity and net positive feedback. Higher climate sensitivity means a larger climate response to CO2 forcing. Past climate change actually provides evidence that humans can affect climate now.

Its always in equilibrium because it gives off energy while getting it.