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97% Scientist Consensus: global warming is man-made

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Re: 97% Scientist Consensus: global warming is man-made

Postby Henry Vilas » Thu Nov 14, 2013 8:37 am

Like Sandi, I doubt if Bludgeon has much understanding of science or its methods.
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Re: 97% Scientist Consensus: global warming is man-made

Postby DCB » Sat Nov 23, 2013 10:08 pm

This posting puts global temperatures in a historical context, going back 540 million years. He concludes that we're all gonna die.

He assumes the most pessimistic scenario, because really, is the US going take the threat seriously? Not as long as we keep electing climate deniers.
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Re: 97% Scientist Consensus: global warming is man-made

Postby johnfajardohenry » Fri Nov 29, 2013 7:44 pm

Just got back yesterday from a sustainability conference in Germany.

The keynote speaker Monday morning was a British "Futureologist" He would have warmed the cockles of many hearts here. 45 minutes of standard warmist "We're all gonna die!" doom and gloom. He did have one interesting take on the melting of the Arctic ice cap. When it does melt, as he assured us it will, it will cut 7-10 days off shipping times between China and Europe. (He had apparently never heard of the SS Manhattan)

Still a pretty interesting speaker and I enjoyed chatting with him after.

What I thought was even more interesting was the 15-20 minute talk he did to close the conference.

He was talking about all the doom and gloom books of the 60's and 70's. He specifically mentioned the Club of Roman, Ehrlich (The Population Bomb), Toffler (Future Shock) and some others. His point being that forecasting the future is pretty much "science fiction" (his phrase). He mocked them mercilessly for being pretty much completely wrong about everything.

I chatted with him again over coffee after the conference and wanted to ask him if he thought the predictions of climate change would go the same way. The conference sponsor was also there, though and I didn't want to bite the hand that feeds me or put him in that position.

The point I took away was that in 5-10 years even Madisonions will be wondering "How in the Hell did I ever believe that climate change bullshit?" Much as they are likely doing now about books like Population Bomb and Future Shock.

Don't really even have to wait. None, not a single on, of the predictions associated with climate change has come to pass. It does seem to take a long long time for these things to sink into some heads, though.

John Henry
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Re: 97% Scientist Consensus: global warming is man-made

Postby johnfajardohenry » Fri Nov 29, 2013 7:52 pm

Caveat to the above:

I am repeatedly told here that warming temperatures were predicted and have been observed and so there has been one prediction that came true.

Yes, IF temperatures have actually increased (by 0.8 deg. Or is it 0.65 now?), this would have been a valid prediction that came true. There are so many problems with the way temperature data has been collected and manipulated that it takes a real leap of faith to believe in it. Yes, temps may have increased by 0.8 over the past 100 years. Or they may have decreased by 0.8. Or they may have stayed the same or changed even more either positively or negatively.

I've discussed the various problems with the temperature data in various threads here before and will be happy to do so again if anyone wishes. For the moment, I'll just say that I find it completely untrustworthy.

John Henry
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Re: 97% Scientist Consensus: global warming is man-made

Postby Sandi » Sat Nov 30, 2013 5:14 am

Image
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Re: 97% Scientist Consensus: global warming is man-made

Postby kurt_w » Sun Dec 01, 2013 12:54 pm

johnfajardohenry wrote:I am repeatedly told here that warming temperatures were predicted and have been observed and so there has been one prediction that came true.

Yes, IF temperatures have actually increased (by 0.8 deg. Or is it 0.65 now?), this would have been a valid prediction that came true. There are so many problems with the way temperature data has been collected and manipulated that it takes a real leap of faith to believe in it. [...]

I've discussed the various problems with the temperature data in various threads here before and will be happy to do so again if anyone wishes. For the moment, I'll just say that I find it completely untrustworthy.


Let's take this one piece at a time.

(1) Predictions:

Two early papers containing quantitative predictions of global warming were Broecker et al. 1975 and Hansen et al. 1981, discussed in detail here and here respectively.

Writing in 1975, Broecker et al. predicted approximately 0.8C of warming from the mid-1970s to the early 2010s, as shown in their Figure 1:

Image

Meanwhile, Hansen et al. predicted approximately 0.5C of warming by the early 2010s, as shown in their Figure 6:

Image

It is worth noting that both papers occurred at the end of a period of 30 years of basically flat temperatures globally. Thus, both Broecker et al. and Hansen et al. were predicting a radical change from current conditions at the time -- they were not merely extrapolating an existing warming trend.

(2) Observations:

Here is the actual global temperature trend -- or rather, two completely independent versions of the global temperature trend.

The blue lines show global mean temperature based on measurements at meteorological stations (on land) and from ships (prior to 1979) and satellites (since 1979) for the ocean.

The red lines show global mean temperature measurements since 1979 from a completely different set of satellite instruments (microwave sounders, which measure temperature-dependent emissions of microwave radiation from the lower atmosphere).

In both cases, the thin lines are monthly averages and the thick lines are three-year smoothed trends (using a statistical filter know as LOESS).

Image

Note that the MSU satellite observations lie almost exactly on top of the land & ocean observations. Thus, we have two completely independent sets of data showing basically the exact same warming trends from 1979-present.

This negates John Henry's concern about the reliability of the temperature data. Since there is no connection between the methods or sources used to produce the two data sets, the fact that they show similar trends is very strong evidence for their accuracy.

(3) Comparison of Predictions and Observations:

In this figure, I have overlaid the actual, observed temperature data on top of Broecker's predictions from 1975:

Image

It is evident that Broecker's model (green line) slightly over-predicted warming. One issue is that Broecker's model assumed that the earth would respond rapidly to a climate forcing, whereas in reality there are time lags in the climate, such that the effect of an instantaneous warming will be smeared out over a period of decades.

Meanwhile, Hansen's 1981 prediction somewhat under-estimated warming:

Image

Note that recent temperatures have been at or above the top of the range of predicted values in Hansen's paper.

This is, frankly, astonishing. Working at a time when only very sketchy global temperature data were available, and when computers were primitive compared to today's, two separate research groups managed to come up with highly accurate predictions of global warming.

I don't blame John Henry for not knowing about this, since the media have generally done a terrible job of reporting on climate science issues in the US.

But in point of fact, we can say with a high degree of confidence that the earth has warmed since the 1970s, and that the early, path-breaking predictions of Broecker et al. and Hansen et al. have turned out to be remarkably accurate.
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Re: 97% Scientist Consensus: global warming is man-made

Postby kurt_w » Sun Dec 01, 2013 2:39 pm

Let's examine some more predictions.

First, sea level rise. Here is the range of predicted sea level rise for a "Business-As-Usual" emissions scenario, in the very first IPCC report way back in 1990:

Image

And here is the comparison with global measurements of sea level rise, derived from satellite radar altimeters:

Image

Note that the trend is solidly within the range of predictions from 1990. It is rising slightly slower than the "best estimate" line, but well above the low range of the predictions, and is clearly not following the dashed no-change line.

Sea level rises due to two factors, the melting of ice on land, and the expansion of water in the oceans as its temperature rises. If global warming was not occurring, the sea level measurements would follow the dashed (no-change) line in the above figure. Clearly that is not happening.

So, sea level rise is another example of a successful prediction, in this case by the original IPCC panel from 1990.
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Re: 97% Scientist Consensus: global warming is man-made

Postby kurt_w » Sun Dec 01, 2013 2:58 pm

One area where climate predictions have not been particularly accurate is Arctic sea ice extent and volume.

Here's a graph showing about a dozen model predictions of sea ice extent:

Image

The red line is what has actually happened. (The 2013 value has not yet been added to that graph -- it would be a bit higher than 2012, but still lower than the model predictions).

So I guess one could say that climate scientists have correctly predicted that Arctic sea ice would decrease, but have underestimated the rate of decrease.
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Re: 97% Scientist Consensus: global warming is man-made

Postby snoqueen » Sun Dec 01, 2013 7:18 pm

Which shows conclusively they are a bunch of wingnuts and the whole climate thing is a conspiracy.


There. I saved jfh the trouble of posting a reply.
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Re: 97% Scientist Consensus: global warming is man-made

Postby kurt_w » Sun Dec 01, 2013 8:11 pm

I missed out on most of this thread, having been too busy to check in to the Forum for much of this past year. And at this point, I'm not going to go back and wade through the whole thing.

But even a cursory glance through the back pages of the thread reveals a lot of ... um ... misinformation. Here's just one example, pulled more or less at random:

Sandi wrote:The really big driver of global warming is easy to find. Look at that big bright yellow ball in the sky. Solar activity, especially sun spot cycles do correlate with temperatures without any delay (as the image below shows). Sun spot activity causes an increase in the solar wind, which in turn allows more cosmic rays to hit the earth and clouds: a dramatic factor in earth's weather.

Image
Sunspot activity with the average worldwide "Sea Surface Temperature" (SST).


I'm not sure where Sandi dug up that graph. I can't find it anywhere on the page that was linked to, but maybe I'm just missing something.

But we can reconstruct it from the raw data. I downloaded the raw sunspot number (SSN) data here, and also downloaded the Hadley sea surface temperature data (HADSSTv3). Both of them are monthly, and the sunspot data are strongly affected by the 11-year solar cycle. I had a suspicion that Sandi's graph shows a running average of 132 months (11 years), so I tried plotting the data that way, superimposed on top of Sandi's graph:

Image

Not bad. The lines don't match exactly, but it's obviously close. Maybe whoever created Sandi's graph used a slightly different version of the sunspot and sea surface temperature data.

There does seem to be a bit of correlation between the sunspot and sea surface temperature data. We can see that more clearly by shifting up the temperature line so it lies right on top of the sunspot line:

Image

The two curves aren't perfectly correlated, but they kinda sorta have the same shape.

Except ... why does Sandi's graph stop at 1985? It's 2013 now! We have almost 30 years of additional data that aren't being shown!

Here's the full version, with ALL the data:

Image

Purely by chance I'm sure, Sandi's graph happens to be cut off at exactly the point where the two lines suddenly go in opposite directions. From the 1980s onward, sunspot numbers are plunging to near-record lows, while sea surface temperatures are soaring to record highs.

Something different must be happening to the climate since the 1970s. As Sandi's graph shows, up until that time the solar cycle seems to have at least a modest effect on global temperatures. But since the 1970s, that relationship completely breaks down. It's as if some other force has taken over and is driving the global climate.

If only we had some idea of what that other force could be! It's a real head-scratcher, alright.

:?
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Re: 97% Scientist Consensus: global warming is man-made

Postby rabble » Sun Dec 01, 2013 9:24 pm

I laugh at your "graphs" and your "science" and I shall post a cartoon that irrefutably proves how silly you are!
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Re: 97% Scientist Consensus: global warming is man-made

Postby Galoot » Sun Dec 01, 2013 9:48 pm

Well damn, kurt. Once again, I was about to just abandon this place to the trolls, and here you go and just slap them right into their place. Well done. Thank you.
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Re: 97% Scientist Consensus: global warming is man-made

Postby kurt_w » Sun Dec 01, 2013 9:59 pm

My pleasure, as always. But thanks for the kind words.
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Re: 97% Scientist Consensus: global warming is man-made

Postby gargantua » Sun Dec 01, 2013 11:25 pm

I'm sorry I don't have a link but I know other Forons are well read and may have already seen this. I've seen articles that indicate that scientists are puzzled by a lack of solar activity.

The speculation that accompanied this is that a "Little Ice Age" may result. Has anyone else seen this?

Please understand. I am convinced that human activity can affect the climate. I also believe that nature can overcome those efforts, depending upon the timing. If we are in fact at risk of global cooling due to solar inactivity or Maunder Minima (look it up), I'm not sure we're worrying about the right thing. Again, if we were in a regime of high solar activity, it would be a completely different issue. Not a big Ice Age fan, sorry.
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Re: 97% Scientist Consensus: global warming is man-made

Postby Mad Howler » Sun Dec 01, 2013 11:58 pm

1) kurt_w cares.
2) kurt_w is very skilled.
3) Whether you, I or kurt_w likes it or not - this individual speaks his/her trade as an honest harbinger.
Let us see where the data takes us.
Let us see what we might choose to do with said...

These decisions will, obviously, be difficult.
Although, probably not as difficult as we are led to believe.
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