My writings are grouped under the topic headings above. New items live here on the home page until I get around to filing them. Peer-reviewed articles are denoted **. Invited and edited articles or chapters are denoted *.
July 24, 2014
NEW PAPER ON THE MISSING TROPICAL HOTSPOT
MODEL-OBSERVATION COMPARISON 1958-2012 IN THE TROPICAL TROPOSPHERE
Tim Vogelsang and I have published a paper in Environmetrics called
In it we compare the temperature trends in climate models over the 1958-2012 interval in the tropical troposphere to those observed in weather balloon data. The models tend not only to over-predict observed warming, but also to represent it differently. Models exhibit a relatively smooth upward trend, whereas observations show almost all the warming took place in a single jump in the late 1970s and the trend either side is practically and statistically zero. Since the tropical troposphere is where models predict the maximum response to GHG forcing should be observed, the absence of a significant trend there over a 55-year interval is a serious inconsistency. Data and code are here. A discussion at Climate Audit is here.
Newspaper Columns, Commentary and Other
THE ENVIRONMENTAL CRISIS: THE DEVIL IS IN THE LACK OF DETAILS
I spoke to a new organization called the Canadian Sustainable Use Network (CSUN) at its inaugural meeting, June 24 2014, at the School of Public Policy, University of Calgary. My talk focused on the need to stop thinking about the environment as one big abstract crisis and start seeing it as it really is, namely thousands of different issues, many of which aren't problems or which used ot be but aren't any more, and all of which exhibit their own complex aspects and attributes.
My presentation (powerpoint) is here. Partway into it I switched to a web browser to give the audience a guided tour of YourEnvironment.ca.
THE GLOBAL WARMING HIATUS, aka DISCREPANCY
I have a column today (June 17 2014) in the Financial Post on the widening discrepancy between models and observations. The talk of the "pause" in global warming is somewhat misplaced, since a pause is not out of place amidst a long term upward trend. What is out of place is an extended pause just where models predict a sharp rise. That's the issue that merits attention, both for the scientific issues it gives rise to, and also the potential policy implications. NOTE: the line shades were mislabeled in the article--black should be gray and vice-versa. The above graph has the correct shading. R code to draw that graph is here.
A BRIEF RETROSPECTIVE ON THE HOCKEY STICK:
In Spring 2014 I was invited to contribute a chapter to a forthcoming volume by the Institute for Policy Analysis in Australia on the subject of climate change. I was specifically asked if I would discuss the hockey stick episode, and it seemed an appropriate time to survey the story once again. Here is the result.
They wanted it fairly short, which meant it took much longer to write than if they'd asked for a long piece. Often I'd just be finishing the introduction and realize I'd hit the word limit. So naturally it doesn't provide an exhaustive treatment, but the reference list gives the reader plenty of additional leads. The book version is due out this fall and I hope you will consider supporting the project.
THE DOWNSIDE OF ENERGY CONSERVATION:
May 23 2014: A correspondent has asked me on Twitter what is the downside of energy conservation. Twitter being what it is, rather than try to go through all the reasoning in 160-character snippets, I have written up a 2-page note in reply. My thanks to @cswaine for the query.
ENERGY ABUNDANCE AND ECONOMIC GROWTH
Along with PhD candidate Elmira Aliakbari, I have published a report for the Fraser Institute on the relationship between energy and economic growth. It might seem obvious that energy is important for growth, but a surprising number of policymakers and activists (e.g.) seem to think that cutting energy consumption is an important end in itself. We review econometric evidence from around the world, supplementing it with some new results on Canadian data, that indicates a Granger causal connection between energy abundance and GDP growth.
I am very pleased to announce the launch of yourenvironment.ca, a new project of mine. The idea is very simple: to present the complete environmental record of every community across Canada. The site currently shows air emissions by source (back to 1985), air contaminant levels (back to 1974) and monthly average high temperatures (back to 1900) for hundreds of places across the country. Water pollution data are coming this summer.
The layout is self-explanatory and it's very easy to use. The data are all from government agencies, but most of it has not hitherto been disseminated in a usable form to the public. All my sources are, or will soon be, linked and the data I use will all be easily-downloadable.
So the next time you find yourself in a conversation with someone who (i) is convinced that Canada does nothing to protect the environment, or (ii) thinks winters around here used to be a lot colder/longer/snowier; or it never used to be this warm/cold in April/October/ etc, or (iii) worries/guffaws about the alleged/obvious ecological disaster all around us, and you wonder what, if any, of this is true, look at yourenvironment.ca and find out.
I especially hope households with high school students will learn about it, though from the experience at our home it might put some kids at risk of being expelled.
Journal Articles and Discussion Papers
MEASURING THE LENGTH OF THE PAUSE IN GLOBAL WARMING
I'm a big fan of the VF method for measuring confidence intervals around deterministic trends. It is robust to autocorrelation of unknown length and has very stable size (i.e. null rejection probabilities stay close to the nominal 5% rate in simulations of different sample sizes and autocorrelation profiles) yet retains power better than many non-parametric methods do. So with the question now at hand regarding how long the global warming hiatus is, the VF method seems eminently suited to providing an answer. I've written a short methodology paper proposing a couple of robustness requirements for such a measurement and I apply the resulting definition to the HadCRUT4 and RSS data.
AVERAGE HOUSEHOLD SIZE AND THE DISAPPEARANCE OF MALARIA
I have completed a project with Finnish biologists Lena and Larry Hulden looking at explanatory factors for the pattern of malaria eradication around the world. We have found that declining average household size plays a big role, as does income. What doesn't play a role? Average temperature, among other things. We can't find any indication that a change in a country's climate will make malaria worse - in fact if anything, warmer temperatures are associated with less malaria, once the effects of income and household size are controlled for. The paper has just appeared in the Journal of the Royal Statistical Society.
A detailed but non-technical discussion is here.
The data/code archive is here (note the readme file).