Heat Waves

August 5, 2019

“At a press conference in New York, U.N. Secretary General António Guterres announced that the month of July had reached 1.2 degrees Celsius above pre-industrial levels, a figure that “at least equaled if not surpassed the hottest month in recorded history,” according to data released by the World Meteorological Organization. Temperature information from July is still streaming in, but preliminary data show last month’s warmth is roughly on par, or perhaps slightly warmer than the previous record of July 2016.” Rolling Stone. August 1, 2019

July 17: “Dangerously high temperatures are expected to spread across the Central and Eastern United States on Wednesday through the weekend, with temperatures soaring above 100 degrees Fahrenheit in the hardest-hit places, the National Weather Service has warned.” [i]

July 25, 2019: “Never in recorded history has Paris been hotter than it was on Thursday, when the temperature neared 110 degrees. The same was true of Belgium, Germany and the Netherlands, as a dangerous heat wave scorched Western Europe.” [ii]

“On June 28, 2019, a temperature of 45.9°C was recorded at a weather station in France, exceeding the country’s previous temperature record—set during the infamous 2003 heatwave—by almost 2°C. The heatwave peaked over central and northern Europe, fuelled by a very persistent planetary-scale Rossby wave (giant meanders in upper-tropospheric winds), which turned into an omega block, so named because its shape resembles the Greek letter (Ω). This blocking event led to hot air from northern Africa being transferred to Europe ….. Given the extraordinary nature of this event, the public and media are now wondering: is such weather the new norm, and how bad could it get in the future?” [iii]

“The  2018 National Climate Assessment, a major scientific report by from 13 federal agencies, notes that while the peak of extreme heat in the United States occurred during the 1930s Dust Bowl, the number of hot days is increasing, and the frequency of heat waves in the United States jumped from an average of two per year in the 1960s to six per year by the 2010s. Also, the season for heat waves has stretched to be 45 days longer than it was in the 1960s, according to the report. It is all part of an overall warming trend: The five warmest years in the history of accurate worldwide record-keeping have been the last five years, and 18 of the 19 warmest years have occurred since 2001; worldwide, June was the hottest ever recorded.”[iv]

“Scientists may disagree about how fast the atmosphere is warming or what the best solutions are, but except for a small number of outliers, none doubt that we are rapidly approaching climate catastrophe. That a few misguided politicians believe climate change predictions are exaggerated or even fabricated is lamentable. But perhaps more puzzling is the lack of alarm among the general public. As monumental hurricanes lash out in Houston and Puerto Rico and California forests burn out of control, it would seem that the evidence that climate scientists are right would be clear enough.” [v]

“A colorful cast of characters has made a living out of denying the science of climate change. These so-called “experts” often start out their statements with “I’m not a climate scientist, but…” before launching into a series of carefully rehearsed talking points meant to confuse the public on the climate change issue. Many of them are well-paid operatives of organizations like The Heartland Institute, CFACT, and Americans for Prosperity, which take contributions from fossil fuel corporations — including ExxonMobil, the Koch Brothers and their company Koch Industries — who seek to delay or block any substantial government policy initiatives meant to curb fossil fuel emissions or hasten the rapid growth of cheaper, cleaner sources of energy like wind and solar power.” [vi]

“In many ways, climate denialism resembles cancer denialism. Businesses with a financial interest in confusing the public — in this case, fossil-fuel companies — are prime movers. As far as I can tell, every one of the handful of well-known scientists who have expressed climate skepticism has received large sums of money from these companies or from dark money conduits like DonorsTrust …..”

July 9:  Time Magazine: “President Donald Trump has falsely called climate change a “hoax” invented by China, incorrectly suggested that wind turbines cause cancer and dismissed a landmark scientific report produced by the federal government’s own scientists. His Administration has sought to roll back key climate regulations at every turn.” [vii]

“An increase in anxiety disorders, depression symptoms, posttraumatic stress and behavioural disorders can be observed in children and adolescents after an EWE”[viii]. [EWE=extreme weather event]

“Extreme weather and climate events affect human health by causing death, injury, and illness, as well as having large socioeconomic impacts. Climate change has caused changes in extreme event frequency, intensity, and geographic distribution, and will continue to be a driver for change in the future.” [ix]

“Continued warming will be accompanied by changes in precipitation, which will vary across the country and seasons, and by increasing climate variability and extreme weather events. Climate change will likely drive the emergence of infectious diseases in Canada by northward spread from the United States and introduction from elsewhere in the world via air and sea transport. Diseases endemic to Canada are also likely to re-emerge.”[x]

“Evidences of the impact of climate change are available for malaria, arbovirus diseases such as dengue, and many other parasitic and viral diseases such as Rift Valley Fever, Japanese encephalitis, human African trypanosomiasis and leishmaniasis. The effect of temperature and rainfall change as well as extreme events, were found to be the main cause for outbreaks and are alarming the global community. Among the main driving factors, climate strongly influences the geographical distribution of insect vectors, which is rapidly changing due to climate change.” [xi]

 “We identified 54 studies conducted in 20 countries. In total, there were significant associations between heatwaves and cardiovascular mortality (risk estimates (RE): 1.149, 95% confidence interval (CI): 1.090, 1.210) and respiratory mortality (RE: 1.183, 95%CI: 1.092, 1.282….. For mortality, significant associations were observed for the elderly, ischemic heart disease, stroke, heart failure, and chronic obstructive pulmonary disease. Sensitivity analyses suggested that these findings were robust.” [xii]

2007: British Journal of Psychiatry: “METHOD: Time-series regression analysis was used to explore and quantify the relationship between daily suicide counts and daily temperature. The impact of two heatwaves on suicide was estimated. RESULTS: …. Above 18 degrees C, each 1 degrees C increase in mean temperature was associated with a 3.8 and 5.0% rise in suicide and violent suicide respectively. Suicide increased by 46.9% during the 1995 heatwave, …..” [xiii]

“The health risks of a changing climate will become increasingly urgent as climate change affects the quantity and quality of food and water, increases air pollution, alters the distribution of vectors/pathogens and disease transmission dynamics, and reduces eco-physical buffering against extreme weather and climate events. Health systems urgently need to be improved to effectively address these emerging challenges.” [xiv]

2013:  “…. researchers are now quantifying the causal relationship between extreme climate and human conflict. Whether their focus is on small-scale interpersonal aggression or large-scale political instability, low-income or high-income societies, the year 10,000 B.C. or the present day, the overall conclusion is the same: episodes of extreme climate make people more violent toward one another.

In a paper published this month in the journal Science, we assembled 60 of the best studies on this topic from fields as diverse as archaeology, criminology, economics, geography, history, political science and psychology. Typically, these were studies that compared, in a given population, levels of violence during periods of normal climate with levels of violence during periods of extreme climate. We then combined the results from those studies that concerned modern data in a “meta-analysis,” a powerful statistical procedure that allowed us to compare and aggregate findings across the individual studies.

We found that higher temperatures and extreme rainfall led to large increases in conflict: for each one standard deviation change in climate toward warmer temperatures or more extreme rainfall, the median effect was a 14 percent increase in conflict between groups, and a 4 percent increase in conflict between individuals.  The studies in our analysis covered all major regions of the world and showed remarkably similar patterns across a wide range of settings. For example, they documented that spikes in temperature increased violent crime in the United States and Australia, that years of low rainfall increased domestic violence and ethnic conflict in South Asia, that extreme rainfall events increased land invasions in Brazil and that warmer temperatures increased civil conflict throughout the tropics. These studies also documented the role that climate played in the collapse of many of human history’s iconic civilizations: the Akkadian empire in Syria around 2000 B.C., the Maya in Mexico in the ninth century A.D. and Angkor Wat in the 1400s…..” NY Times 2013 [xv]

“In this review, we survey this literature on the interlinkages between climate and conflict, by necessity drawing from both economics and other disciplines given the inherent interdisciplinarity of research in this field. We consider many types of human conflict in the review, including both interpersonal conflict — such as domestic violence, road rage, assault, murder, and rape — and intergroup conflict — including riots, ethnic violence, land invasions, gang violence, civil war and other forms of political instability, such as coups. We discuss the key methodological issues in estimating causal relationships in this area, and largely focus on “natural experiments” that exploit variation in climate variables over time, helping to address omitted variable bias concerns. After harmonizing statistical specifications and standardizing estimated effect sizes within each conflict category, we carry out a hierarchical meta-analysis that allows us to estimate the mean effect of climate variation on conflict outcomes as well as to quantify the degree of variability in this effect size across studies. Looking across 55 studies, we find that deviations from moderate temperatures and precipitation patterns systematically increase the risk of conflict, often substantially, with average effects that are highly statistically significant. We find that contemporaneous temperature has the largest average effect by far, with each 1σ [1]increase toward warmer temperatures increasing the frequency of contemporaneous interpersonal conflict by 2.4% and of intergroup conflict by 11.3%, but that the 2-period cumulative effect of rainfall on intergroup conflict is also substantial (3.5%/σ). We also quantify heterogeneity in these effect estimates across settings that is likely important.” Full text of paper: [xvi]

2018:  “The national murder rate reached a modern low in 2014, capping a quarter-century decline. Then it rose across the United States in 2015 and 2016. Why gun violence increased in those two years remains somewhat of a mystery, and no single factor is likely to explain it, but there is one potential contributor that is rarely talked about: the weather.

Temperatures across the country were higher on average in those two years than they were in 2014. The relationship between temperature and crime has been discussed for decades. Fewer people are murdered in America during colder months than during warmer ones.

In the case of 2015 and 2016, it may be a small part of the story, but the broader correlation of weather and crime merits more research. Let’s look at 10 cities that make daily shooting data available and then compare shootings in each city with the day’s high temperature according to the National Oceanic and Atmospheric Administration.

For each of the 10 cities in recent years, it’s possible to calculate the average number of shooting victims per cold day (defined here as under 50 degrees Fahrenheit), per pleasant day (50 to 84) and per hot day (85 and up).

In Philadelphia, for example, there were 2.6 shooting victims per day on average when it was cold, 3.4 on pleasant days, and 4.4 on hot ones.

On average, about twice as many people are shot in Northern cities like Chicago, Milwaukee and Detroit when it’s hot versus when it’s cold (only nonfatal shooting victim data was available for the latter two). In Southern cities like Atlanta and New Orleans, the effect exists but is weaker ….”

Fatal and nonfatal shooting victim data for Cincinnati (2008-present), Rochester (2000-present), San Francisco (2012–2017), Baltimore (2011-present), Philadelphia (2015-present), New Orleans (2010-present), Atlanta (2012–17) and Chicago (below, 2014-present).


[1]Sigma:  In statistics, the standard deviation (SD, also represented by the lower case Greek letter sigma σ for the population standard deviation or the Latin letter s for the sample standard deviation) is a measure that is used to quantify the amount of variation or dispersion of a set of data values.









Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz. 2019 May;62(5):599-604. doi: 10.1007/s00103-019-02937-7.[Extreme weather events and their impact on the mental health of children and adolescents].Mambrey V1, Wermuth I2, Böse-O’Reilly S3,4.

DOI: 10.1007/s00103-019-02937-7


[x]  https://www.ncbi.nlm.nih.gov/pubmed/31285696

Can Commun Dis Rep. 2019 Apr 4;45(4):76-80. doi: 10.14745/ccdr.v45i04a01. eCollection 2019 Apr 4. Climate change and infectious diseases: What can we expect? Ogden NH1,2, Gachon P3.


[xii]Environ Res. 2019 Jul 26;177:108610. doi: 10.1016/j.envres.2019.108610. [Epub ahead of print] Cardiorespiratory effects of heatwaves: A systematic review and meta-analysis of global epidemiological evidence. Cheng J1, Xu Z1, Bambrick H1, Prescott V2, Wang N1, Zhang Y1, Su H3, Tong S4, Hu W5.


Relationship between daily suicide counts and temperature in England and Wales. Br J Psychiatry. 2007 Aug;191:106-12. Page LA, Hajat S, Kovats RS.



[xvi]Climate and Conflict. NBER Working Paper No. w20598. 22 Oct 2014Marshall Burke Solomon M. Hsiang Edward Miguel. http://www.nber.org/papers/w20598