Editing Heat wave (section)

=== Psychological and sociological effects ===
Excessive heat causes psychological stress as well as physical [[stress (biology)|stress]]. This can affect performance. It may also lead to an increase in violent crime.<ref name="heat and stress">{{cite journal |last=Simister |first=John |author2=Cary Cooper |title=Thermal stress in the U.S.A.: effects on violence and on employee behaviour |journal=Stress and Health |volume=21 |issue=1 |pages=3–15 |date=October 2004 |doi=10.1002/smi.1029 |doi-access=free }}</ref> High temperatures are associated with increased conflict between individuals and at the social level. In every society, [[crime]] rates go up when temperatures go up. This is particularly the case with violent crimes such as assault, murder and rape. In politically unstable countries, high temperatures can exacerbate factors that lead to civil war.<ref>{{cite journal |last1=Hsiang |first1=Solomon |last2=Burke |first2=Marshall |last3=Miguel |first3=Edward |title=Climate and Conflict |journal=Annual Review of Economics |volume=7 |issue=1 |pages=577–617 |year=2015 |doi=10.1146/annurev-economics-080614-115430 |s2cid=17657019 }}</ref>

High temperatures also have a significant effect on income. A study of countries in the United States found that the economic productivity of individual days declines by about 1.7 percent for each degree Celsius above {{convert|15|°C|°F}}.<ref>{{cite journal |last1=Solomon |first1=Hsiang |last2=Tatyana |first2=Deryugina |title=Does the Environment Still Matter? Daily Temperature and Income in the United States |journal=NBER Working Paper No. 20750 |date=December 2014 |doi=10.3386/w20750 |doi-access=free }}</ref>