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Bishop Hill Jan 15, 2015 Climate: Surface The Berkeley Earth Surface Temperature project have reported their results for 2014:
The global surface temperature average (land and sea) for 2014 was nominally the warmest since the global instrumental record began in 1850; however, within the margin of error, it is tied with 2005 and 2010 and so we can’t be certain it set a new record.
Bishop Hill Dec 15, 2014 BBC Climate: Surface Perhaps it's because it's the season of goodwill. Or perhaps because Greenpeace's vandalism of the Nazca lines has put Corporation noses out of joint. Whatever the reason, the BBC's decision to highlight the recovery in Arctic sea ice levels in the last few years represents a rare excursion out of its "OMG we're all about to fry" comfort zone.
Yes, the sea ice is going to disappear, we are told, but on much longer timescales than previously advised.
While global warming seems to have set the polar north on a path to floe-free summers, the latest data from Europe's Cryosat mission suggests it may take a while yet to reach those conditions.
The spacecraft observed 7,500 cu km of ice cover in October when the Arctic traditionally starts its post-summer freeze-up.
This was only slightly down on 2013 when 8,800 cu km were recorded.
Two cool summers in a row have now allowed the pack to increase and then hold on to a good deal of its volume.
Bishop Hill Dec 10, 2014 Climate: RC Climate: Statistics Climate: Surface I'd like to commend to readers a couple of postings on the subject of statistical significance in the temperature records.
Last week a little visited website called Real Climate had an article by climatologist Stefan Rahmstorf, which addressed many of the issues discussed here in recent months. What I found interesting was that there was a measure of agreement:
...the confidence intervals (and claims of statistical significance) do not tell us whether a real warming has taken place, rather they tell us whether the warming that has taken place is outside of what might have happened by chance.
Bishop Hill Dec 9, 2014 Climate: MetOffice Climate: Surface I was amused by this new paper out of the Met Office which describes a computer model study of the likelihood of future heatwaves. The title reads like something out of the Daily Mirror rather than a learned scientific paper:
Dramatically increasing chance of extremely hot summers since the 2003 European heatwave
The abstract that follows is equally odd. Take the first sentence:
Socio-economic stress from the unequivocal warming of the global climate system could be mostly felt by societies through weather and climate extremes.
Bishop Hill Dec 8, 2014 Climate: MWP Climate: Surface Matt Ridley Matt Ridley has one of those pieces in the Times that is just going to get Bob Ward's blood boiling. He covers the scandal over the neonicotinoid "research", the Met Office's claims about record temperatures and the revelations over the Sheep Mountain data, wrapping them all up in a sorry tale of scientists dropping their standards in the endless search for money and relevance.
The overwhelming majority of scientists do excellent, objective work, following the evidence wherever it leads. Science remains (in my view) our most treasured cultural achievement, bar none. Most of its astonishing insights into life, the universe and everything are beyond reproach and beyond compare. All the more reason to be less tolerant of those who let their motivated reasoning distort data or the presentation of data. It’s hard for champions of science, like me, to make our case against creationists, homeopaths and other merchants of mysticism if some of those within science also practise pseudoscience.
In all the millions of scientific careers in Britain over the past few decades, outside medical science there has never been a case of a scientist convicted of malpractice. Not one. Maybe that is because – unlike the police, the church and politics – scientists are all pure as the driven snow. Or maybe it is because science as an institution, like so many other institutions, does not police itself properly.
It's paywalled, but well worth it if you have access.
Bishop Hill Nov 24, 2014 Climate: Models Climate: Surface Via Nic Lewis and Frank Bosse comes a link to a page at the Berkeley Earth Surface Temperature project (BEST). Richard Muller and his team have compared their results to the output of a series of GCMs and the results are not exactly pretty, as one of the headlines explains
Many models still struggle with overall warming; none replicate regional warming well.
Bishop Hill Nov 6, 2014 Climate: Surface Climate: WG2 Professor Mark Maslin, a climatologist from University College London, has written an article for The Conversation to mark the publication of the Synthesis Report of AR5. In it he makes some remarkable claims, for example:
We have tracked significant increase in global temperatures of 0.85°C and sea level rise of 20cm over the past century.
Changes in precipitation are also expected to vary from place to place. In the high-latitude regions (central and northern regions of Europe, Asia and North America) the year-round average precipitation is projected to increase, while in most sub-tropical land regions it is projected to decrease by as much as 20%, increasing the risk of drought.
I wonder if he is going to try to make a defence of his article. If you head over to the Conversation, do stay polite and on topic. Several BH regulars are already there.
Bishop Hill Nov 4, 2014 Climate: Surface Snow in Scotland was at one time said, somewhat notoriously, to be a thing of the past. What then to make of Helen Rennie, who has apparently skied in the Cairngorms in 61 consecutive months?
RT @theiaincameron: Today, Helen Rennie skied on last season's snow at Ciste Mhearad, Cairn Gorm. That's month 61. pic.twitter.com/t2YgzqGZSD
— MCofS (@MCofS) November 4, 2014
Bishop Hill Oct 31, 2014 Climate: Surface Richard Treadgold emails with details of an interesting new paper, with quite an eye-opening end to the abstract.
Yesterday a paper on the New Zealand temperature record (NZTR) was accepted by Environmental Modeling & Assessment. Submitted in 2013, we can only imagine the colossal peer-review hurdles that had to be overcome in gaining acceptance for a paper that refutes the national temperature record in a developed country. The mere fact of acceptance attests to a fundamental shift in scientific attitudes to climate change, but expect strident opposition to this paper.
Bishop Hill Oct 30, 2014 Climate: Models Climate: Surface John McLean, of James Cook University in Australia, emails with details of a paper he has just had published in Atmospheric and Climate Sciences about the warming of the planet at the end of the last century. He adds a useful layman's summary.
The paper ...
- indicates that the temperature pattern can be attributed to a sequence of events, namely a shift in the prevailing ENSO conditions, then a reduction in total cloud cover and then a shift on cloud (decrease in low level cloud that was largely offset by an increase in mid and upper level cloud)
- uses the Trenberth, Fasulo & Kiehl energy balance diagram to show that the loss in total cloud cover caused an increase in heat energy being absorbed at the Earth's surface that was greater than the increase that IPCC 5AR claims was due to greenhouse gases
Bishop Hill Oct 29, 2014 Climate: Surface I can barely keep up with all the climate and energy stuff on the airwaves in the last couple of days. Last night Matt Ridley and Tamsin Edwards were on Newsnight discussing the enigma of the increasing Antarctic sea ice. This was preceded by a review of recent theories about the science presented by Helen Czerski, which was pretty good really, and in particular touched on what I consider to be the key point: that if the models fail to predict changes in the ice then there is something missing in the models. This Eureka moment was then closely followed by Evan Davis noting that global warming is "all about the models".
Perhaps we are getting somewhere.
Video here, from 34:00.
Bishop Hill Oct 17, 2014 Climate: Surface Greens The latest chapter in the saga of Peter Wadhams attempts to bully and threaten those who ridiculed his ridiculous Arctic ice predictions at a Royal Society meeting a few weeks ago has just been made public. Wadhams, it seems, has written to the meeting's organisers and to senior officials once again. Once again the response has been to make the good professor's missive public so that everyone can laugh at him. The letter is vastly enlivened by the annotations that have been added. I particularly enjoyed number 7, commenting on Wadhams assertion that the proper place for criticism of his work is in a scientific journal:
First Prof Wadhams cannot tell people where and how to debate science. Secondly the irony of Prof Wadhams using graphs from uncredited blog pages in his RS presentation and yet calling for discussion only in journals seems to have escaped him.
There is also a strong hint that Wadhams makes a habit of this sort of behaviour.
Bishop Hill Oct 10, 2014 Climate: Surface Climate: WG2 Karl Mathieson, the journalist who replaced Leo Hickman on the Guardian's ecoaudit thread seems to be doing a good job of raising interesting questions. I'm not sure the readership are quite living up to the premise of the thread, namely that they should provide scientific insights into the questions asked, but you can't say that Mathieson isn't trying.
Yesterday he raised the irritating - for climate modellers at least - question of the Antarctic sea ice and his article has several interesting points. Not least of which was this:
Dr Claire Parkinson, a senior scientist at Nasa’s Goddard Space Flight Centre, says increasing Antarctic ice does not contradict the general warming trend. Overall the Earth is losing sea ice at a rate of 35,000 sq km per year (13,514 sq miles).
If one looks at the graph of global sea ice area, I can imagine that a straight line fit through the record might have a weeny bit of a downwards trend. A loss of 35000 km2 out of something like 19 million km2 is, however, only a loss of 0.1% per year; and given that sea ice is currently above its long term average, it would be presumptious to suggest that this is anything other than natural variability. I would say that therefore that it does contradict the general warming trend.
Bishop Hill Oct 1, 2014 Climate: Surface Greens Tom Nelson is having some fun with uber-ecoperson Bill McKibben who has been tweeting about an AP story in SFGate about a huge congregation of walruses on the coast of Alaska. SFGate helpfully provides a photo:
According to the story, this so-called `haulout' is down to climate change:
The gathering of walrus on shore is a phenomenon that has accompanied the loss of summer sea ice as the climate has warmed.
Which is the kind of statement to get McKibben going of course.
Bishop Hill Sep 29, 2014 Climate: Statistics Climate: Surface Doug Keenan has posted a strong critique of Ross McKitrick's recent paper on the duration of the pause at his own website. I am reproducing it here.
McKitrick [2014] performs calculations on series of global surface temperatures, and claims to thereby determine the duration of the current apparent stall in global warming. Herein, the basis for those calculations is considered.
Much of McKitrick [2014] deals with a concept known as a “time series”. A time series is any series of measurements taken at regular time intervals. Examples include the following: the maximum temperature in London each day; prices on the New York Stock Exchange at the close of each business day; the total wheat harvest in Canada each year. Another example is the average global temperature each year.
The techniques required to analyze time series are generally different from those required to analyze other types of data. The techniques are usually taught only in specialized statistics courses.
