Today (March 9), my local paper ran a story with a LA Times byline titled Study of 11,300 years suggests record warming ahead. Here is the link to the LA Times article.
I tried to read the paper on which the article was based and could have…except I’m too cheap. Science wanted me to pay for it. So I took a pass. There are three reasons I decided not to pay for the article.
- The promotional tease on the Science website made direct reference to IPCC data. It looked like the study was using existing IPCC work as a basis for its predictions.
- The LA Times article was full of errors that made me wonder.
- The study period and the number of sites looked odd.
Point 1 – Promo problems
The promo tease on the Science website says the following:
Current global temperatures of the past decade have not yet exceeded peak interglacial values but are warmer than during ~75% of the Holocene temperature history. Intergovernmental Panel on Climate Change model projections for 2100 exceed the full distribution of Holocene temperature under all plausible greenhouse gas emission scenarios.
It looks like this article is simply assuming that existing IPCC emission scenarios are plausible and correct. Scenarios prepared in 2005 and published in 2007. Sounds like old news to me. And besides….so far at least…. the IPCC predictions have been wrong. We were supposed to be 0.2 degree C warmer in first 10 year of the 21st century and another 0.2 degree C warmer by 2020. So far (March 2o13) there has been no net change.
Point 2 – LA Times errors.
My favorite paragraph demonstrating errors concerns rising sea level.
While a 1-degree Fahrenheit increase sounds small, it represents an enormous amount of heat energy. For instance, a 10-degree drop would plunge the world into another period of major glaciation, while every 1.8-degree increase would gradually amount to a roughly 65-foot rise in sea level due to melting polar ice, according to NASA climatologist James Hansen.
Just about everything in the paragraph is incorrect or misleading, except the first sentence, which is correct. We have had a 1 degree C rise (1.8 F) in the last 250 years and sea level did not go up 65 feet. The same 2007 IPCC Synopses Report that the Science tease noted has specific sea level predictions (table 3.1 on page 45). Their predictions for the year 2100, using 1990-2000 as a base, look like this:
Case Best Estimate (C) Temp Range (C) Sea Level Rise (m) BI Scenario 1.8 1.1-2.9 0.18-0.38 AIT Scenario 2.4 1.4-3.8 0.20-0.45 B2 Scenario 2.4 1.4-3.8 0.20-0.43 AIB Scenario 2.7 1.7-4.4 0.21-0.48 A2 Scenario 3.4 2.0-5.4 0.23-0.51 A1F1 Scenario 4.0 2.4-6.4 0.26-0.59
The absolute worst possibility according to the IPCC would be a 6.4 degree C rise and that would lead to an increase of .59 meters, about 1.93 feet. Why the discrepancy? Time. Which leads to another error of the article. The sea level rise is not because of polar ice melting.
If the temperature stays warm long enough, the deep oceans begin to change temperature. The complete cycle takes about a thousand years. As the oceans warm, the water expands. Notes associated with chart 3.1 note that additional sea level rise is probable at the rate of a foot per century as the deep oceans warm. So far at least, most warming noted since the Industrial Revolution has been on land and in Northern Latitudes.
Arctic polar melting has absolutely no impact on sea level. That ice is floating and is less dense than the water it displaces. Consider ice in a soda, it does not flood the glass if you let it melt. Ice melting in Greenland and Antarctica would change sea level, but not by the 65 feet noted in the article.
The 10 degree F statement in the article is almost right. Our world would be a very nasty place with only 5 degrees F of cooling. The little ice age was warmer than that and lots of really bad things happened.
That’s a lot of mistakes for just one paragraph!
Point 3 – Incomplete and Oddly Chosen Data
Why did the study begin at a climate peak? I see nothing but benefit by adding just a little more time. Add 1000 years and rapid warming shows up, albeit from a very cold base. A study of that warming would be invaluable in attempting to understand the differences between man made and natural warming. Go back another five thousand years and the world is a really nasty place and 10 degrees F cooler.
The Times article says the study uses 17 locations for the entire world. Sure it’s better than the Hockey Stick Graph which is infamous because it used questionable mathematics and had one proxy consisting of just 2 trees at a single location; but 17 sites for the whole world is still a relatively small number.
The IPCC data shown (table 3.1) has a wide range of estimates because there is lots of variation in the models it runs. This study used 17 sites and referenced IPCC data sets. Which Scenario, which data set, interpolation between sites and data sets? I see lots of guessing. It does look like a step forward from the Hockey Stick Graph, but there’s still too much guessing, particularly if IPCC data is used a a predictor.
I’m hopeful that the actual article in Science is better than the LA Times story it is based upon, but I have doubts. So I didn’t pay to see the article.