An Inconvenient Comment

RealClimate: Saleska Responds (green is green)

2010-03-20T14:23:00.000-07:00

March 20th, 2010

In a recent post here at RealClimate, Simon Lewis wrote regarding a 2010 paper by Samanta et al. on the effect of single-year drought conditions on the Amazon. Samanta et al. claimed to have contradicted a 2007 paper by Scott Saleska et al., and to have thereby overturned some IPCC conclusions.

Lewis showed why Samanta’s paper did not contradict the IPCC, even if it may have correctly identified an error in Saleska et al. Now Saleska has written to say that, actually, Samanta et al.’s results do not identify any error in their work: the results agree completely. With our apologies for the journalistic whiplash, Simon Lewis and I are convinced he’s right. The more general point though, is that the the balance of evidence shows that the Amazon is sensitive to drought, and the IPCC’s statements about it remain valid.
Here is Saleska’s commentary in full

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RealClimate: Up is Down, Brown is Green (with apologies to Orwell)

2010-03-19T13:45:00.000-07:00

March 15th, 2010

In the alternate universe of Fox News, Anthony Watts, and many others, up is down. Now, it appears, brown is green. Following the total confusion over the retraction of a paper on sea level, claims of another “mistake” by the IPCC are making the rounds of the blogosphere. This time, the issue is the impact of rainfall changes on the Amazon rainforest.

A study in 2007 showed that the forest gets greener when it rains less. A new study, by Samanta et al. in Geophysical Research Letters shows that the earlier work was flawed. Aided by an apparently rather careless press release, this is being used as evidence that the Amazon is less sensitive to rainfall changes than the IPCC claimed. But the Samanta et al. paper actually does not address the central questions at all. It only addresses whether a single anomalous rainfall year had an impact that is measureable and interpretable from a satellite sensor. The conclusion is that they could not detect a change. As noted in a commentary from Simon Lewis, University of Leeds, “the critical question is how these forests respond to repeated droughts, not merely single-year droughts.”

Lewis – a broadly published expert on tropical forests – makes a number of additional important points in his commentary below. Bottom line: IPCC gets it right as usual.

Open Mind: Still Not

2010-03-19T13:43:00.000-07:00

March 16th, 2010

Those who can’t bear to believe that the laws of physics govern global temperature, still want to maintain that it’s a random walk. They base this on the fact that the ADF (Augmented Dickey-Fuller test) doesn’t reject the presence of a unit root, if you refuse to use the BIC (Bayesian Information Criterion) for model selection and you’re willing to ignore the Phillips-Perron unit root test.

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RealClimate: A mistaken message from IoP?

2010-03-07T13:12:00.000-08:00

March 6th, 2010

The Institute of Physics (IoP) recently made a splash in the media through a statement about the implications of the e-mails stolen in the CRU hack. A couple of articles in the Guardian report how this statement was submitted to an inquiry into the CRU hack and provide some background.

The statement calls for increased transparency, and expresses concerns about the public confidence in science if the transparency is absent. The IoP statement, however, fails to note that the issue of transparency is far more general applicable than just to mainstream climate science. It should also involve the critics of climate change, as noted by New Scientist.

RealClimate: Arctic Methane on the Move?

2010-03-07T13:10:00.000-08:00

March 6th, 2010

Methane is like the radical wing of the carbon cycle, in today’s atmosphere a stronger greenhouse gas per molecule than CO₂, and an atmospheric concentration that can change more quickly than CO₂ can. There has been a lot of press coverage of a new paper in Science this week called “Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic Shelf”, which comes on the heels of a handful of interrelated methane papers in the last year or so. Is now the time to get frightened?

Open Mind: Message to Anthony Watts

2010-03-05T12:45:00.000-08:00

March 5th, 2010

Anthony:

It has now been independenly confirmed, by multiple persons, that my results regarding the impact of station dropout on global temperature are correct. Your claims, in your document with Joe D’Aleo for the SPPI, are just plain wrong.

Open Mind: Global Update

2010-03-05T12:43:00.000-08:00

March 5th, 2010

I’ve finished processing the southern hemisphere GHCN data, and computed the temperature according to the simple procedure for the entire globe.

RealClimate: Climate change commitments

2010-03-03T11:39:00.000-08:00

March 3rd, 2010

There is an interesting letter in Nature Geoscience this month on what climate changes we have actually already committed ourselves to. The letter, by Mathews and Weaver (sub. reqd.), makes the valid point that there are both climatic and societal inertias to consider.

Their figure neatly demonstrates the different issues:

Open Mind: Replication, not repetition

2010-03-02T16:55:00.000-08:00

March 1st, 2010

By now it’s clear to many readers that others have replicated my results. There’s even one at the blackboard.

Perhaps some industrious reader would consider it worthwhile to scour the net and find out just how often the results have now been confirmed. Then, of course, visit WUWT and ask Anthony Watts whether he’s willing to admit that the false claims in his document with Joe D’Aleo are wrong.

In the meantime, I’ll continue preparing for publication.

Climate Progress: Foreign Policy’s “Guide to Climate Skeptics” includes Roger Pielke, Jr...

2010-03-01T00:02:00.000-08:00

February 28th, 2010

Warning: Please put your head in a vise before reading further.

Andy Revkin has just written the most illogical climate post on Earth. Or maybe he’s written the most logical climate post on the Bizarro World Htrae.

Revkin asserts (here) that a key litmus test of whether the IPCC is serious about restoring its credibility and good name is if it puts Roger Pielke, Jr. (!!!) on the author team of a special panel report, “Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation.”

Seriously.

Read the rest of the post at the source…

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Open Mind: Interesting Comment

2010-02-28T23:58:00.000-08:00

February 25th, 2010

There’s a most interesting comment on Anthony Watts’ blog:

Open Mind: Shame

2010-02-28T23:56:00.001-08:00

February 25th, 2010

Two of the most prominent claims of global warming denialists have been proven wrong.
This raises two very serious issues. First, it’s certainly possible to “run the numbers” in order to check the truth or falsehood of their claims, but they didn’t bother to do so. I have. For them to make the claims they’ve made, without even doing the work require to find out, is fundamentally dishonest.

Open Mind: False Claims Proven False

2010-02-28T23:55:00.000-08:00

February 25th, 2010

Two of the most prominent claims of global warming denialists have proven to be utterly false.
I’ve completed processing the GHCN data for the northern hemisphere. This project was undertaken to investigate two denialist claims: 1st, that the dramatic reduction in the number of reporting stations around 1990 introduced a false warming trend; 2nd, that the adjustments applied to station data also introduce a false warming trend.

Open Mind: Snow

2010-02-28T23:53:00.000-08:00

February 22nd, 2010

Steven Goddard doesn’t know when to quit. Sad.
But far more interesting than showing him the error of his ways, is to take a look at northern hemisphere snow cover. Here’s the weekly snow cover since satellite observations began:

and here’s the weekly snow cover anomaly:

Open Mind: Cherry Snow

2010-02-28T23:51:00.000-08:00

February 18th, 2010

Anthony Watts has a new post by Steven Goddard about northern hemisphere snow cover. There’s plenty of snow in the northern hemisphere right now — an exceptional amount. This last week saw the 2nd-highest weekly average ever recorded in the data available from the Rutgers University Global Snow Lab. As we’re well aware, an exceptional event doesn’t mean there’s a trend. But Steven Goddard thinks there is. He even shows this graph:

and tells us that wintertime snow cover is increasing at 100,000 km^2 per year.

RealClimate: Close Encounters of the Absurd Kind

2010-02-28T23:49:00.000-08:00

February 24th, 2010

A recent story by Fred Pearce in the February 9th online edition of the Guardian (“Victory for openness as IPCC climate scientist opens up lab doors”) covers some of the more publicized aspects of the last 14 years of my scientific career. I am glad that Mr. Pearce’s account illuminates some of the non-scientific difficulties I have faced. However, his account also repeats unfounded allegations that I engaged in dubious professional conduct. In a number of instances, Mr Pearce provides links to these allegations, but does not provide a balanced account of the rebuttals to them. Nor does he give links to locations where these rebuttals can be found. I am taking this opportunity to correct Mr. Pearce’s omissions, to reply to the key allegations, and to supply links to more detailed responses.

RealClimate: The Guardian disappoints

2010-02-28T23:47:00.000-08:00

February 23rd, 2010

Over the last few weeks or so the UK Guardian (who occasionally reprint our posts) has published a 12-part series about the stolen CRU emails by Fred Pearce that are well below the normal Guardian standards of reporting. We delineate some of the errors and misrepresentations below. While this has to be seen on a backdrop of an almost complete collapse in reporting standards across the UK media on the issue of climate change, it can’t be excused on the basis that the Mail or the Times is just as bad. As a long-time Guardian reader and avid Guardian crossword puzzle solver, I’m extremely unhappy writing this post, but the pathologies of media reporting on this issue have become too big to ignore.

RealClimate: Throw your iPhone into the climate debate

2010-02-28T19:02:00.000-08:00

February 19th, 2010

Who says that the climate debate is not evolving? According to the daily newspaper the Guardian, a new application (‘app‘) has been written for iPhones that provides a list of climate dissidents’ arguments, and counter arguments based on more legitimate scientific substance. The app is developed by John Cook from ‘Skeptical Science‘. It’s apparently enough to have the climate dissidents up in arms – meaning that it’s likely to have some effect? Some dissidents are now thinking of writing their own app.

Open Mind: Growthgate

2010-02-17T13:55:00.000-08:00

February 16th, 2010

Suppose you have a child, a son — he’s 10. You want to know whether or not he’s growing normally, so every day you measure his height with a tape measure. You’ve done so since he was 5. You even plot the data on a graph, and notice two things about it. First: the measurements show a fair amount of jitter, sometimes they’re a wee bit higher, sometimes a wee bit lower, there’s noise in the data. Second: there’s also a trend. Your kid is a lot taller at 10 than he was at 5, in fact the trend over the observed time span is upward and reasonably steady. You even do a statistical analysis, estimate the growth rate, and determine that it’s definitely statistically significant — so it’s not a false trend due to noise in the data, it’s real. Your son is growing normally.

RealClimate: Whatevergate

2010-02-17T13:53:00.000-08:00

February 16th, 2010

It won’t have escaped many of our readers’ notice that there has been what can only be described as a media frenzy (mostly in the UK) with regards to climate change in recent weeks. The coverage has contained more bad reporting, misrepresentation and confusion on the subject than we have seen in such a short time anywhere. While the UK newspaper scene is uniquely competitive (especially compared to the US with over half a dozen national dailies selling in the same market), and historically there have been equally frenzied bouts of mis-reporting in the past on topics as diverse as pit bulls, vaccines and child abductions, there is something new in this mess that is worth discussing. And that has been a huge shift in the Overton window for climate change.

Open Mind: Summer and Smoke

2010-02-15T16:19:00.000-08:00

February 15th, 2010

One of the section titles in D’Aleo and Watts’s denialist document is “NO WARMING TREND IN THE 351-YEAR CENTRAL ENGLAND TEMPERATURE RECORD.” It comes from a site calling itself “carbon sense.” Only when you read the section do you discover that it only compares 100-year averages of the 20th century to the 18th century, and only for the summer season. In fact their entire case is just smoke and mirrors.

Open Mind: Dropouts

2010-02-15T16:18:00.000-08:00

February 15th, 2010

We’ve already critiqued the analytical skills of Joe D’Aleo and of course the incomparable Anthony Watts….. Incomparable.
They’ve joined forces to create a document which pretends to ask the question, “SURFACE TEMPERATURE RECORDS: POLICY DRIVEN DECEPTION?” but is really just a bunch of false claims intended to state outright that the surface temperature record is not just mistaken, it’s fraudulent.

RealClimate: Daily Mangle

2010-02-15T16:16:00.001-08:00

February 15th, 2010

Yesterday, the Daily Mail of the UK published a predictably inaccurate article entitled “Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995″.

The title itself is a distortion of what Jones actually said in an interview with the BBC. What Jones actually said is that, while the globe has nominally warmed since 1995, it is difficult to establish the statistical significance of that warming given the short nature of the time interval (1995-present) involved. The warming trend consequently doesn’t quite achieve statistical significance. But it is extremely difficult to establish a statistically significant trend over a time interval as short as 15 years–a point we have made countless times at RealClimate. It is also worth noting that the CRU record indicates slightly less warming than other global temperature estimates such as the GISS record.

RealClimate: IPCC errors: facts and spin

2010-02-14T16:19:00.000-08:00

February 14th, 2010

Currently, a few errors –and supposed errors– in the last IPCC report (“AR4″) are making the media rounds – together with a lot of distortion and professional spin by parties interested in discrediting climate science. Time for us to sort the wheat from the chaff: which of these putative errors are real, and which not? And what does it all mean, for the IPCC in particular, and for climate science more broadly?

Open Mind: Prime Meridian

2010-02-14T16:18:00.000-08:00

February 13th, 2010

I’ve decided to average the GHCN station data in gridboxes which are 10 deg. latitude tall, and approximately the same width. That makes them 600 nautical miles tall, which is a bit over 1100 km. Within that range, we can expect that all stations which inhabit the same grid box will show correlation with each other. The exception to the “10 deg. tall” rule will be stations north of 70N latitude — instead of defining separate grid boxes for stations north of 80N latitude, I’ll lump them together with the stations north of 70N latitude.