John Christy and I have published a new paper in the Journal of Hydrology:
The published version is temporarily available at this link. If that does not work a pre-print is available here. The Supplement is here. We look at the claim (made by the recent US National Climate Assessment) that US precipitation increased over the 20th century, that precipitation extremes did likewise and that confidence is high that this is due to greenhouse gases. We discuss 2,000 year drought proxies that reveal Hurst behaviour (long term persistence) which means spurious trend detection is a risk. We replicate the NCA finding on 2 regional data sets, both for average precipitation and for various measures of extreme rainfall. We then show that the trend inferences don't hold up when the data are extended back into the 1800s and that the trend signs reverse on the last 4 decades of the sample, which is the opposite of what should happen if GHG's are driving the changes. We conclude that natural variability is likely the dominant driver of historical changes in precipitation and hence drought dynamics in the US regions we examine.
SEPTEMBER 12, 2019
LONG-TERM US DROUGHT AND PRECIPITATION TRENDS
Newspaper Columns, Commentary and Other
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.
AN OPEN LETTER TO LISA RAITT, MP
Like many MPs, Lisa Raitt finds herself asking some legitimate and reasonable questions about what we're being told about climate change. And like many MPs, when she does so out loud, she comes face to face with an increasingly angry climate mob. I got wrapped up in this situation when she retweeted an op-ed of mine, then was quickly bullied and harassed into deleting the tweet and apologizing for it. What was my op-ed about? A scientist who published research contradicting some aspects of climate alarmism, who was eventually bullied and harassed into leaving the field. There's a pattern here, and an important lesson that we all need to learn while there's still time.
CORRECTING FALSE CLAIMS IN THE NYC LAWSUIT
The City of New York has filed a lawsuit against a group of large oil and gas companies including Exxon Mobil, alleging among other things that they conspired to mislead the public about the dangers of global warming. Paragraph 87 of the complaint alleges that I was paid by Exxon to do the "hockey stick" work for the Fraser Institute. The claim is completely false and the paragraph is full of untrue statements. I have issued this statement in response:
FIVE QUESTIONS ABOUT CLIMATE CHANGE
In late 2017 I was contacted via email by a group of high school students in Europe who asked if I would answer some questions about global warming for a project they were doing. Here are the questions they posed, and the answers I gave them.
Journal Articles and Discussion Papers
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.
TESTING THE MAJOR HYPOTHESIS IN CLIMATE MODELS
John Christy and I published a paper in Earth and Space Science, a publication of the American Geophysical Union:
There has been a lot of discussion about the relative lack of observed warming in the tropical troposphere compared to model projections. We confirm the mismatch using three 60-year weather balloon records. We also outline four criteria for a valid test of the major component of interest in climate models, namely the moist thermodynamics in the troposphere that generates amplified global warming in response to rising greenhouse gases. The criteria are measurability, specificity, independence and uniqueness. The 200-300mb layer in the tropics satisfies all four, pretty much uniquely in the climate system, making it very suitable as a test target. The results clearly show that models misrepresent a process fundamental to their usability for studying the climate impacts of greenhouse gases.
EMPIRICALLY-CONSTRAINED CLIMATE SENSITIVITY AND THE SOCIAL COST OF CARBON
I have completed a study with Kevin Dayaratna of the Heritage Foundation in Washington DC and David Kreutzer of the EPA, which recomputes standard Social Cost of Carbon (SCC) estimates using updated empirical estimates of the equilibrium climate sensitivity (ECS).