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NEWEST ITEMS
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TRENDS AND PATTERNS IN U.S. DAILY TOTAL AND EXTREME PRECIPITATION SINCE 1893
John Christy and I have completed a draft of a major study on US daily precipitation since the late 1800s.
What sets this analysis apart is that John assembled the longest continuous daily precipitation record ever for 377 locations across the United States. While daily records are available through NCEI back to 1895, there are many missing entries and a particular tendency for extremes not to be recorded. John manually checked hundreds of thousands of handwritten daily precipitation records against the NCEI archives and not only corrected and filled in the records where needed but extended them back in time, in some cases into the 1870s. We then ran trend regressions on all the major metrics of precipitation (e.g. annual average, skewness and max), on three time periods, 1893 or earliest to 2025, 1958 to 2025 and 1980 to 2025, allowing us to evaluate our findings against those of NCA5. We also conducted nonstationary GEV analyses to assess the role of global warming in driving changes in extreme precipitation. We reproduce earlier findings showing the Northeast got wetter after 1958 but we are not able to support the blanket generalizations about trends and extremes that the NCA5 put forward. |
APRIL 15, 2026 TIME SERIES ANALYSIS OF US DAILY PRECIPITATION SINCE THE LATE 1800s. |
RECENT ITEMS
Newspaper Columns, Commentary and OtherCANADA AT A CROSSROADS
Today (February 11, 2025) marks the start of a new series I am writing for the MacDonald-Laurier Institute called Canada at a Crossroads. Each volume will examine a pressing issue in public policy that a new government needs to address. VOLUME 1: THE HOUSING CRUNCH
VOLUME 2: THE FERTILITY CRISIS
VOLUME 3: REFORMING INCOME TAXES
VOLUME 4: BOOSTING INVESTMENT
VOLUME 5: REBUILDING CANADA'S HERITAGE
VOLUME 6: REFORMING UNIVERSITIES
SOME RECENT NEWSPAPER OP-EDS
COMPLETE LISTING HERE March 26, 2026 Carney’s Industrial Carbon Tax imposes real costs on Canadians financialpost.com/opinion/opinion-carneys-industrial-carbon-tax-imposes-real-costs-on-canadians February 13, 2026 Carney practises the illusion of EV mandate repeal financialpost.com/opinion/carney-ev-mandate-repeal January 30, 2025 Face reality. Net zero is neither affordable nor attainable financialpost.com/opinion/opinion-net-zero-neither-affordable-nor-attainable April 2, 2024 Economists’ letter misses the point about the carbon tax revolt financialpost.com/opinion/carbon-tax-economists-letter-misses-point February 15, 2024 Canada's Eagle Pass symbolizes unity, America's exemplifies crisis financialpost.com/opinion/canada-eagle-pass-symbolizes-unity-america-exemplifies-crisis April 12, 2023 The important climate study you won't hear about financialpost.com/opinion/ross-mckitrick-the-important-climate-study-you-wont-hear-about TEMPERATURE TRENDS IN CANADA SINCE 1888
We hear a lot about climate change. Would someone who lived in, say, 1918 notice much change in the average weather conditions compared to today? Once you delve into temperature data you will see that it's very hard to offer a simple answer to such a question. Patterns vary over time, by season and by place. For those Canadians who are curious about how the climate might have changed near where they live, I have written a rather lengthy report on the subject.
Or rather, I wrote an R program that generated a lengthy report. I analyze long term records on monthly average daytime highs in Canada, in various segments based on collections of stations available back 40, 60, 80, 100 and 130 years. There are also some nice graphs. If you think you know what "climate change" looks like in Canada, now you can test your perceptions against the data. The R program is here. 
Yourenvironment.ca
The idea of this site is very simple: to build the complete environmental record of every community across Canada. The site currently shows air emissions by source (back to 1990), air contaminant levels (back to 1974), monthly average high temperatures (back to 1900) for hundreds of places across the country, and water pollution records for several provinces. 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 linked and the data I use are easily-downloadable. So the next time you find yourself in a conversation about some aspect of the environment and you wonder what is actually going on, look at yourenvironment.ca to find out. |
Recent Journal Articles and Discussion PapersCLIMATE CHANGE AND ECONOMIC GROWTH
My PhD student Devina Lakhtakia and I have a paper accepted at Climate Change Economics
Preprint HERE. In it we address the question of how temperature affects income and income growth. There is already a large literature, but most of it depends on using national-level economic data and requires averaging gridded climate data over large spatial and population groups, which detracts from the robustness of the results. We use location-specific flight data and satellite-read night lights data to generate economic measures at the gridcell level. We also address some common regression misspecifications especially endogeneity bias. We find mixed effects of warming on local income depending on temperature and income levels. We also find that warming has no permanent effect on economic growth. DATA and CODE archive here. CONSISTENT CLIMATE FINGERPRINTING
I have a paper at Climate Dynamics which responds to Chen et al. (2023) and sets out a consistent method for signal detection in climate science.
When I say this method is consistent I am using the statistical concept of consistency. It is my assertion, based on several previous publications, that the IPCC method (based on Allen and Tett 1999 and Allen and Stott 2003) yields biased and inconsistent signal detection coefficients and is uninformative for the purpose of GHG attribution. The method I propose relies on Instrumental Variables estimation with Conley SAC-robust errors. There's nothing new about it, only the application. I show in an empirical example that the IPCC method (which I call P-TLS) implies a much larger role for anthropogenic forcing than the consistent approach. I present standard model specification tests (for the first time ever in an optimal fingerprinting application as far as I know) to show why the consistent model is the preferred specification. UPDATE (July 16): Climate Dynamics invited Chen et al. to write a response to my article which was to appear alongside mine but which for some reason they published 2 months prior. My reply to their comment is published at SSRN. EXTENDED CROP MODEL DATA SET SHOWS NO YIELD LOSSES FOR CO2-INDUCED WARMING
A few years ago the Biden administration hiked its estimate of the Social Cost of Carbon, thus triggering a large number of new regulations on CO2 emission sources. A big part (about $50 worth) of the upward revision was due to a 2017 study arguing that warming would have much worse effects on crop yields than hitherto expected. I noticed that the 2017 study reached very different conclusions than a 2014 study that had used the same data. So I set out to try and understand why. The result is the following paper:
Both studies used a data set created by surveying several decades' worth of crop yield modeling studies. I obtained the data set and saw that despite it having about 1700 rows, half were missing the CO2 data and were therefore unusable. I looked into the underlying data sources and found several hundred of the missing CO2 entries. I found I could replicate the 2017 results showing negative crop yield effects from climate warming based on the incomplete data set, but when I added in the missing data the results all changed and the negative effects vanished, thus matching the 2014 findings. Basically the extra CO2 fully compensates for any negative effects of warming even out to 5C warming, across all crop types and in all regions. I conclude the upward revision to the SCC due to the supposed crop yield losses was unwarranted. ECONOMIC IMPLICATIONS OF A PHASED-IN EV MANDATE IN CANADA
I have published a paper in the Canadian Journal of Economics looking at the Canadian plan to mandate 100% EV sales by 2035:
The key message is that an EV mandate is only affordable if it is also unnecessary. If you have to force people to switch to EVs the policy will push the auto sector into permanent losses. The key question is the pace at which EVs achieve cost parity. "Cost parity" doesn't just mean being able to buy an EV sedan for $30k. It means that across all vehicle classes, taking account of all purchase, maintenance and fuel costs, people are completely indifferent between EVs and internal combustion engines (ICEVs); analogous to the switch from LPs to CDs. If we reach cost parity by 2035 the mandate will be very costly but the economy will return to trend and the auto sector will probably survive albeit shrunken. But in that case the mandate is unnecessary. If cost parity takes longer and the mandate forces involuntary switching, the economic costs get very large very quickly and the auto sector goes into permanent losses. I simulate the outcome assuming 2050 cost parity and find the auto sector gets wiped out and the macroeconomic impacts are very painful. For the reasons stated in the paper I don't think it is realistic to expect EV cost parity by 2035, so my expectation is for the latter scenario. |
