2) Can you extend the graph from the start of the Holocene period to now? Without out using smoothing on the base data and adding a beginning to end average line?

Recent sediment studies conducted by the USGS in the LA basin found 16 major climate change events in the Pleistocene, each measuring on average 120 meters in sea level shift, about 90 meters below present to 30 meters above. Ice core data from Vostok and Dome Concordia tells us these happen on the most regular clock in all of geology, nice regular, dramatic and unavoidable climate shifts, with temperature increases leading CO2 increases by an average 1,300 years on the major shifts, and temperature decreases leading CO2 decreases by an average 2,700 years. Meaning, of course, that just like us, CO2 has been a spectator at these major and abrupt climate shifts, and not an agent provocateur. That doesn’t mean CO2 can’t cause a climate change, only that it never has before. So if it takes an industrial revolution and 6 plus billion H. sapiens to cause a 2 foot (IPCC) or 20 foot (the Gorical) rise in sea level, what does it take to cause the 400 footers that are so regular we set our geologic clocks by them?

But not to cast too much doubt on the prowess of prediction, I do indeed have a favorite. Recently I read that the Arctic ice cap is expected to be completely melted away by 2070. This was a shocker for not all that long ago I read that sedimentologists working the Arctic have recently speculated that the trigger event that seems to send us abruptly into the next ice age is the complete melting away of the arctic ice cap…………..

Now if we are going to somehow engineer a reversal of a 2 or 20 foot rise in sea level against a backdrop of natural rise many times (possibly orders of magnitude) greater, doesn’t this strike you as something like an ant crawling up an elephant’s leg with rape on its mind? And what about population, it is predicted to be 10 billion by 2050. And how about rainforests, which were predicted in 2001 to be gone in just a few decades, a prediction in dire straits of coming true due to the advent of biofuels and the doubling in Amazon rainforest devastion this year alone.

Facts, pesky little things aren’t they?

There are points of ambiguity. If anyone can fill them in, that would be great!

OTOH, if emissions refer to human activities only, actual Co2 increases must pretty closely match(if not exceed) Hansen’s predicted levels for A.

Cheers,

I think what would be useful would be to see a graph of the actual GHG forcings over the last 20 years, not just the actual total forcings. Based on actual GHG forcings, my guess is that we should be comparing Hansen’s predictions to something slightly greater than Scenario B due to the increasing growth rate in CO2.

Thanks, but haven’t annual emissions increased over the interval? I.e., doesn’t B underestimate actual emissions?

The graphs shown above describe the situation, probably better than I did. Scenario B has linearly increasing forcing; cumulative emissions rise, but the annual rate of emission is constant. Scenario C caps forcing in 2000; the rate of emission drops drastically. Lucia’s caption is correct, interpreting “emission” as rate of emission (which I agree is probably normal usage).

Again, I would refer to the graphs – decide yourself which emission scenario best describes what has actually occurred.

BTW, in suggesting that GISS met station index is perhaps the one to compare, I’m not suggesting that it is the best. I’m only saying that it is probably closest measure to what Hansen was predicting, since it was probably the only index available at the time, and was the one he used in his plot.

The second chart describes the scenarios as:

1. Scenario A: Continued growth rate in emissions at 1.5% / year.
2. Scenario B: Emissions frozen at 1988 rates.
3. Scenario C: Drastic reductions in emissions in 1990.

That doesn’t match Nick’s description:

“Scenario C capped CO2 emissions in 2000. Scenario A has exponential growth…B, …is the one with linear growth in CO2 emission.”

What’s up? And, what is the actual emissions growth rate?

Lucia has sort of alluded to this already, but I’m not sure why you say this:

“I didn’t see your point about scen B and C diverging. It looks like we’ll be following B for a while, so that’s the only one that counts. The prediction is been on the high side for the last two years, but is not too far away.”

If the GHG between B and C are used in the model, and the model doesn’t distiguish between the two until late this decade, how can the model be tested? Why do you say that only B matters?

And for what it’s worth, we’re now closer to C than to B, even using Hansen’s preferred data. What if I were to say, “it looks like we’ll be following C for a while, so that’s the only one that counts”?

Anyway, climate skeptic already compared to UAH. I’m not sure how he baselined, but the scenarios don’t look good against the satellites. The only way to make them look good is to stick to land only measurements, measured using land based methods. You need to omit measurements over the ocean.

Nick Stokes thinks using the land only measuremetns is fine, I’m dubious about it. In a few years, we should have sufficient spread between all scenarios to know for sure.

Bill

see http://energybulletin.net/node/45651

I used my own eyeball technique to compare real CO2 with Lucia’s real forcing graph. I took the forcing graph and overlaid the NOAA CO2 concentration graph that I found at Anthony Watts’ blog. After stretching the abscissa to match the time scale, I scaled the CO2 concentration to match the Real Forcing w/o volcanoes from 1958 to 1988 (Dr. Hansen’s data, I presume).

From that fit, I believe the CO2 concentration plot represents the form of Hansen’s correlation to the real 1958-88 forcing data. This may be the cause and effect that led Hansen to conclude “… there is only 1 percent chance of an accidental warming of this magnitude, the agreement with the expected greenhouse effect is of considerable significance.”

If this CO2-forcing correlation does actually hold, then the CO2 plot should be a reliable predictor of real forcing without volcanoes after 1988. The CO2 plot does match the real forcing through the early 1990’s, then it diverges from reality, becoming an unreliable predictor by 1995. I think rather than “a greenhouse effect … of considerable significance,” this comparison shows that the “1 percent chance of accidental warming” was what actually happened. Or, despite the outlandish probabilities, someone (Jim Hansen) does win the lottery.

I also note that the CO2 plot adjusted to the early-period real forcing does provide a fantastic fit to Hansen’s Scenario B through the end of the CO2 data. This is where I believe the AGW debate is today – i.e., Who are you gonna believe, Dr. Jim Hansen (NASA Phd!) or your lying ordinary eyeballs?

I think, for various reasons, scenario A is not very useful. And I think the plot you’ve just shown is of the forcings currently used (GISS E). They are lower than those used by Hansen pre-1984.

Nick, the data I plotted may well be what is currently used in GISS Model E, and not measured forcings. However, my plot is exactly the data in the file you referred previously as “actual forcings”, using these words:

Gavin’s graph of the scenarios and the actual forcing is here.

So, if those aren’t actual forcings in my plot, they also aren’t actual forcings in Gavin’s plot you included in comments above.

On the issue of rebaselining.

It’s just an issue of how the forcings are illustrated; the post-1984 forcings aren’t used for any calculations in the plots.

Of course the post-1984 portion of the line in purple or green in my figure aren’t used in Hansen 1988. Neither is the pre-1984 portion of that line.

Supposedly, Hansen used the scenario A, B and C data Gavin provided in the file and indicated as scenarios A,B and C in the legend in my figure and Gavin’s. The purple and green in my figure are supposed to compare what was used to what is “real”. However, it’s not entirely clear the A,B, C data in Gavin’s file are exactly what Hansen used , because if we read the Hansen paper, he included volcanos in A,B and C.

I could cut and past Hansen’s graphics, but they aren’t in KW/m^2, they are in temperature, having been scaled by the models sensitivity. What we would see is that Hansen’s grapic’s don’t precisely match the curves Gavin provides. (I don’t think they were meant to. I think Gavin meant to show GHG increases only.)

With regard to scenario A: You say “scenario A is not very useful”.

If you mean it’s turned out clearly incorrect, I agree. It’s totally wrong.

But the topic of this article is “How did Hansens predictions do?”

In that regard, the results of all scenarios need to be mentioned.

Scenario A results were in the paper; they were presented to Congress. So, clearly, Hansen felt these results should be shown to the public and legislators at the time. When the paper was discussed in Congress, and he didn’t suggest that case as unrealistic or useless. So, in 1988 it was represented as useful as some sort of prediction or projections. Part of the answer to how they did is: Scenario A was wayyyyy off. (For whatever reason.)

That said, the published paper does suggest “B” as the most probable trajectory. So, at least with regard to what Hansen included in the peer reviewed paper, he endorsed “B”. This means the fairest test of the claims in the peer reviewed article are comparisons to “B”.

(We can’t really test what was in Hansen’s inner mind back in 1988. We all know Hansen often makes stronger claims in public than in peer reviewed articles now. Scenario A got a lot of play in the public back in 1988, so mentioning it was totally wrong is far from useless.)

I’m not sure I buy your theory of why Gavin rebaselined. If we are trying to figure out which of the forcings applied to a run was closest to reality, we need to compare the forcings in a run to reality that happened later.

If we consider phenomenology, to compare forcings applied to relatity requires us to see forcing from 1958- now. We know this because incorrect forcing in say, 1960, affects the temperature in 1961, and later 1962 and so on. Since the climate has a finite time constant, and in particular models seem to think the response time is on the order of 20-30 years, the forcing from 1958-1988 sets the initial conditions for what happens later. If the bulk response time of the climate is 30 years, we can’t expect a “wrong” past forcing to be ‘forgotten’ in less than roughly, 30 years. (And saying climate has response times on all scales doesn’t help any.)

So, I really can’t see any rational reason for forcings to 1984 when comparing, particularly as, on Gavin’s chart, Scenario A visibly deviates from B and C around 1965. That’s why A was already hotter than B and C in 1984.

If the reason for rebaselining the forcings is that no one (including Gavin) knows the forcings Hansen used, then figuring out which case best matched the forcings is impossible. In that case, it’s best to simply admit that we can’t know which forcing was closest. If so, all we can do is compare the temperature profiles to what happened. In that case, A look terrible. B and C might look ok if you accept the idea that it makes sense to compare global temperatures to land only data. Otherwise, if we accept the land/ocean data, they all look high.

IF Dave Stephen’s graph at Climate Skeptic showing a relatively poor comparison between satellite data and Hansen’s projections was fair

Before showing graphs and data comparisons, I think it’s important TO NOTE that a question like “How are Hansen’s prediction/projections tracking observations?” is a bit vague.

Here is a graph comparing the linear regression fit to data from 1900 to May 1988, the month before JameS Hansen gave his speech.

So, having prepped you with that graph, I will now superimpose Hansen’s data on figure

(I can adjust this and make another graph iF anyone would like to see that.)

It’s quite clear Scenario A has been over[-]predicting warming for several years. No one disputes this any LONGER. Moreover, the 1990 IPCC projection of 3.0 C/century which may have been influenced by papers written circa 1988 has been largely abandoned.

If we compare the graphs to Climate Skeptic’s, we see we get more or less the same results using land[-]based or satellite data. So, as far as I can tell, his graph seems to fall within the range of “fair comparison”.