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Interactive: Days over 100°F to become more common across US, Hispanics more exposed to 'killer' heat

If decisive action is not taken to mitigate climate change, heat waves will become more frequent nationwide, warns a new report. The analysis of data from the Union of Concerned Scientists reveals that Hispanics will be especially affected.

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

1971-2000

1,060

Counties with a heat index of at least 100°F

0

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

1971-2000

1,060

Counties with a heat index of at least 100°F

0

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

1971-2000

1,060

Counties with a heat index of at least 100°F

0

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

1971-2000

1,060

No county registered 100°F or more.

Counties with a heat index of at least 100°F

0

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

1971-2000

1,060

Counties with a heat index of at least 100°F

0

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

1971-2000

1,060

Counties with a heat index of at least 100°F

0

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

1971-2000

1,060

Counties with a heat index of at least 100°F

0

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

1971-2000

1,060

Counties with a heat index of at least 100°F

0

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

2036-2065

Counties with a heat index of at least 100°F

199

106

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2036-2065

Counties with a heat index of at least 100°F

199

106

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2036-2065

Counties with a heat index of at least 100°F

199

199

106

106

0-1 days

0-1 days

+ of 100

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2036-2065

Counties with a heat index of at least 100°F

199

106

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

2036-2065

Counties with a heat index of at least 100°F

199

106

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2036-2065

Counties with a heat index of at least 100°F

199

106

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2036-2065

Counties with a heat index of at least 100°F

199

106

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2036-2065

Counties with a heat index of at least 100°F

199

106

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

2036-2065

Counties with a heat index of at least 100°F

199

106

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2036-2065

Counties with a heat index of at least 100°F

199

106

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2036-2065

Counties with a heat index of at least 100°F

199

106

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2036-2065

Counties with a heat index of at least 100°F

199

106

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

2070-2099

659

Counties with a heat index of at least 100°F

51

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2070-2099

659

Counties with a heat index of at least 100°F

51

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2070-2099

659

Counties with a heat index of at least 100°F

51

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2070-2099

659

Counties with a heat index of at least 100°F

51

+ of 100

0-1 days

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

2070-2099

659

Counties with a heat index of at least 100°F

51

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2070-2099

659

Counties with a heat index of at least 100°F

51

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2070-2099

659

Counties with a heat index of at least 100°F

51

0-1 days

+ of 100

Number of days per year with a heat index of at least 100°F

0 days

1

10

25

50

75

100

PERIOD

2070-2099

659

Counties with a heat index of at least 100°F

51

+ of 100

0-1 days

For years, temperatures around the world have been increasing. However, historically no county in the US experienced a heat index equal to or greater than 100°F (37.7°C) for more than 100 days a year.

Nearly a third of the US counties (1,060 of 3,109) barely had one day a year with a heat index of 100°F or higher.

Without global action to reduce harmful emissions, only 199 counties in the US would experience a heat index of less than 100°F throughout the year or reach that temperature for a maximum of one day.

Up to 106 counties in the country would register a heat index of at least 100°F for more than 100 days a year for the first time.

Of these, 24 counties - one in four - have a majority of the Hispanic population (en los estados de California, Texas, Arizona y Florida).

If this continues, 22% of the US population, residing in 659 counties, would have a heat index of 100°F or more during 100 days of the year. 30% of the Hispanic population in the US lives in them.

In 2070, in only 51 counties in the US the heat index will be held below 100°F almost all year round.

The new report of the Union of Concerned Scientists is based on the heat index to make projections about the impact of global warming in the country.
This indicator shows the heat “sensation” from the combination of temperature and humidity in the environment. Thus, if the thermostat is 96°F and the relative humidity is 65%, the thermal sensation would be higher, approx. 121°F.
This is important because moisture limits the body's ability to cool. Sweat helps us to lower temperature by evaporation, but humidity hinders the process, which can dangerously elevate the body temperature and trigger diseases associated with heat, or even death.

How many days a year would you have a heat index of at least 100°F?

‘Action’ means the application of global measures that reduce the emission of greenhouse gases.
SELECT YOUR STATE
"If we do not reduce the emission of greenhouse gases, extreme heat will expand drastically," warns the report by the Union of Concerned Scientists, a non-governmental organization of scientists seeking to combat climate change.
As of 100°F, the National Meteorological Service indicates that high temperatures may cause health problems, especially in the case of children or the elderly.
Those who work in the field, buildings or, in general, in the open air are more exposed to high temperatures and humidity. For this reason, the Occupational Health and Safety Administration recommends acclimatizing before doing outdoor activities.

Hispanics will be the most affected by the extreme heat in the middle of the century

Increase in population with a heat index of at least 100°F more than 100 days a year.

Incidence rate in each population group

White

non-Hispanic

5.9%

0%

1971-2000

2036-2065

9.2%

0%

Black

non-Hispanic

16.6%

0%

Hispanic

1 in 6 Hispanics will experience a heat index of at least 100°F more than 3 months per year.

Hispanics will be the most affected by the extreme heat in the middle of the century

Increase in population with a heat index of at least 100°F more than 100 days a year.

Incidence rate in each population group

White

non-Hispanic

5.9%

0%

1971-2000

2036-2065

9.2%

0%

Black

non-Hispanic

16.6%

0%

Hispanic

1 in 6 Hispanics will experience a heat index of at least 100°F more than 3 months per year.

Hispanics will be the most affected by the extreme heat in the

middle of the century

Increase in population with a heat index of at least 100°F more than 100 days a year.

Incidence rate

in each population group

White

non-Hispanic

5.9%

0%

1971-2000

2036-2065

9.2%

0%

Black

non-Hispanic

16.6%

0%

Hispanic

1 in 6 Hispanics will experience a heat index of at least 100°F more than 3 months per year.

Hispanics will be the most affected

by the extreme heat in the middle of the century

Increase in population with a heat index of at least 100°F more than 100 days a year.

Incidence rate

in each population group

White

non-Hispanic

5.9%

0%

1971-2000

2036-2065

9.2%

0%

Black

non-Hispanic

16.6%

0%

Hispanic

1 in 6 Hispanics will experience a heat index of at least 100°F more than 3 months per year.

An analysis of data provided by the Union of Concerned Scientists by Univision News found that 17% of the Latinos in the USA will suffer heat waves (of 100°F or more) during at least 100 days between 2036 and 2065. That incidence rate is 6% higher than the rest of the non-Hispanic population. By late century, the incidence rate for Hispanics rises to 22% for 'killer' heat (105˚F or above) compared to 10% for non-Hispanics.
The Union of Concerned Scientists emphasizes that the actions taken in the coming years will determine how hot we will be in the future.
“We need to mobilize now to avoid the worst consequences of climate change," Juan Declet-Barreto, one of the authors of the report, said in an interview with Univision. "We can significantly reduce the number of days of killer heat (105°F or above) if we take drastic action now."

Methodology: For the report "Killer heat in the United States," scientists from the Union of Concerned Scientists analyzed the frequency in which the National Meteorological Service's heat index reached 90°F, 100°F, or 105°F historically. They also incorporated a series of 18 climate models to project how the heat index will change in the coming decades. They took into account three possible scenarios: 1./ no action is taken to prevent climate change, emissions continue to grow and the global temperature increases 8°F or 4.3°C above pre-industrial levels; 2./ emissions decrease by the middle of this century and by the end of the century they have only increased 4.3°F or 2.4°C (slow action); and 3./ the average global warming is limited to 3.6°F (2°C), as stipulated in the Paris Agreement (fast action). The data does not include Alaska or Hawaii. Population growth or changes in its distribution were not taken into account. Data from the 2010 Census was used.