The World’s Troubling New Tempo of Temperature Records

1880

These dots show yearly global average temperatures compared to an 1880-1900 average

The last eight years have been the hottest eight years on record

2021

2014

+ 0.95˚C

2015

+ 1.10˚C

2016

+ 1.23˚C

Hottest year on record (tied)

2017

+ 1.13˚C

2018

+ 1.06˚C

2019

+ 1.18˚C

2020

+ 1.23˚C

Hottest year on record (tied)

2021

+ 1.05˚C

1880

These dots show yearly global average temperatures compared to an 1880-1900 average

The last eight years have been the hottest eight years on record

2021

2014

+ 0.95˚C

2015

+ 1.10˚C

2016

+ 1.23˚C

Hottest year on record (tied)

2017

+ 1.13˚C

2018

+ 1.06˚C

2019

+ 1.18˚C

2020

+ 1.23˚C

Hottest year on record (tied)

2021

+ 1.05˚C

Source: NASA Goddard Institute for Space Studies

New data from the U.S. government’s temperature takers just ranked 2021 as the sixth-hottest year, near the very top of a list that stretches back into the 19th century. The hottest eight entries in the federal heat records have all occurred in the last eight years.

Last year’s global average temperature was at least 1.04°C above the average from 1880 to 1900, according to reports released Thursday by NASA’s Goddard Institute for Space Studies, NOAA and Berkley Earth, a research nonprofit. A dataset updated on Monday by the EU Copernicus Climate Change Service put 2021 in fifth place for heat.

In a stable climate, without annual re-orderings at the top of the hottest-years list, the world should set hot and cold records about evenly. But as greenhouse gas pollution continues to rise, hot extremes are intensifying and becoming more frequent. Cold spells are becoming weaker and more rare, a major UN-backed assessment concluded in August. Of 458 new regional temperature records counted in one analysis, just 54 were cold extremes.

2021 TOTAL

+1.05˚C

GLOBAL AVERAGE

Source: NASA GISS

The June-to-August average land temperature reached unprecedented highs, and the ocean broke the subsurface annual heat record set in 2020. But even these topline temperature readings can actually conceal how difficult it is for people to cope with consistently higher extreme heat.

2021 TOTAL

+1.45˚C | +0.69˚C

LAND

OCEAN SURFACE

Source: NASA GISS

Record high average temperatures were set in 25 countries last year, even in a year that didn’t end up as the hottest on record. China, South Korea and Nigeria were among them, according to Berkeley Earth.

Ten countries, mostly in the Mediterranean, Middle East and North America, set new national heat records. More than 100 nations registered a highest monthly mark, a rate 21 times higher than cold records, according to Maximiliano Herrera, a climatologist who tracks global temperature records. The Arctic was slightly cooler last year but is still warming two to three times the global average.

“We've had almost a full decade of these elevated temperatures, and it can't help but to have an impact on the weather and on the extremes,” said Gavin Schmidt, director of NASA GISS. “It's not the case that you have to have a record set at the global mean to have lots and lots of records being set locally.”

Where temperature records were broken in 2021

Record

broken by:

+2

+4

+6

+8

+10°C

The areas marked on this globe set new records for local high temperatures in 2021, according to a Bloomberg analysis of Copernicus data.

Not all of these superlatives made global headlines like the heat dome that stretched across the U.S.-Canada border, which scientists in July determined was made at least 150 times more likely by climate change.

Temperatures soared well above 40°C (100°F) in parts of this region, breaking records by unprecedented margins in what had previously been a temperate zone with little need for air conditioners.

Kamloops, British

Columbia

2021

47.3°C/117.4°F

40°C

20

0

−20

JAN

DEC

Seattle-Tacoma

International Airpot

2021

42.2°C/108.0°F

40°C

20

0

−20

JAN

DEC

Portland International

Airport

2021

46.7°C/116.1°F

40°C

20

0

−20

JAN

DEC

Source: NOAA GHCN

A Mediterranean heat wave in August brought Europe a record high as Italy reached 48.8°C (120°F). Snails cooked in their shells. Spain hit 47.4°C, and Tunisia saw 49°C.

One of Pakistan’s typically hottest cities, Jacobabad, reached 52°C in June.

After a deadly cold spell in February, Texas ended 2021 with its hottest-ever December. The states of Montana, Wyoming, Washington and North Dakota also broke records that month.

July 2021 technically became the hottest month ever recorded, according to NOAA, edging out by 0.02°C the prior record set by the Julys of 2016, 2019 and 2020.

Source: Copernicus ECWMF

NASA’s top climate scientist once met skepticism when predicting that 1988 would end as the world’s hottest year. He was right—but now that year seems mild by today’s standards, ranking 28th for heat.

Now predictions of increasing heat are beyond doubt. In fact, greenhouse gas has propelled every decadal temperature average higher than the one before it since the 1960s. Twenty-one of the hottest 22 years since 1880 have occurred in this century, reflected in these maps of heat records from previous years. The pattern is too clear to miss.

Record heat from past years

Record

broken by:

+2

+4

+6

+8

+10°C

2021

The heat dome in western North America stands out even among the past two decades of record-breaking heat

Record-breaking heat

continues to appear

in the Arctic

Two distinct heat waves hit Europe in June and July, killing hundreds

2020

2019

2018

2017

Record heat and drought combined to create historic wildfires in Australia

2016

2015

2014

2013

These were El Niño years, which adds to the general warming trend

Extra heat from El

Niño helped drive

fires in the Amazon

Parts of Russia saw heat records broken by over 10ºC

2012

2011

2010

2009

This was the hottest year on record at the time

2008

2007

2006

2005

Tens of thousands of deaths were attributed to a July heat wave across Europe

2004

2003

2002

2001

Two distinct heat

waves hit Europe

in June and July,

killing hundreds

The heat dome in western North America stands out even among the past two decades of record-breaking heat

Record-breaking heat

continues to appear

in the Arctic

2021

2020

2019

Record heat and drought combined to create historic wildfires in Australia

2018

2017

2016

2015

2014

2013

2015-16 were El Niño years, which adds to the general warming trend

Extra heat from El Niño helped drive fires in the Amazon

Parts of Russia saw heat records broken by over 10ºC

2012

2011

2010

This was the hottest year on record at the time

2009

2008

2007

2006

2005

2004

Tens of thousands of deaths were attributed to a July heat wave across Europe

2003

2002

2001

2021

The heat dome in western North America stands out even among the past two decades of record-breaking heat

Record-breaking heat continues to appear in the Arctic

Two distinct heat waves hit Europe in June and July, killing hundreds

2020

2019

Record heat and drought combined to create historic wildfires in Australia

2018

2017

2016

2015

These were El Niño years, which adds to the general warming trend

Extra heat from El Niño helped drive fires in the Amazon

2014

2013

2012

2011

Parts of Russia saw heat records broken by over 10ºC

2010

2009

This was the hottest year on record at the time

2008

2007

2006

2005

Tens of thousands of deaths were attributed to a July heat wave across Europe

2004

2003

2002

2001

2021

The heat dome in western North America stands out even among the past two decades of record-breaking heat

Record-breaking heat continues to appear in the Arctic

Two distinct heat waves hit Europe in June and July, killing hundreds

2020

2019

2018

2017

2016

2015

Extra heat from El Niño helped drive fires in the Amazon

These were El Niño years, which adds to the general warming trend

2014

2013

2012

2011

Parts of Russia saw heat records broken by over 10ºC

2010

2009

This was the hottest year on record at the time

2008

2007

2006

2005

Tens of thousands of deaths were attributed to a July heat wave across Europe

2004

2003

2002

2001

The heat dome in western North America stands out even among the past two decades of record-breaking heat

2021

Record-breaking heat continues to appear in the Arctic

2020

Two distinct heat waves hit Europe in June and July, killing hundreds

2019

2018

2017

2016

These were El Niño years, which adds to the general warming trend

2015

Extra heat from El Niño helped drive fires in the Amazon

2014

2013

2012

2011

Parts of Russia saw heat records broken by over 10ºC

2010

This was the hottest year on record at the time

2009

2008

2007

2006

2005

2004

Tens of thousands of deaths were attributed to a July heat wave across Europe

2003

2002

2001

The heat dome in western North America stands out even among the past two decades of record-breaking heat

Record-breaking heat continues to appear in the Arctic

Two distinct heat waves hit Europe in June and July, killing hundreds

2021

2020

2019

Record heat and drought combined to create historic wildfires in Australia

2018

2017

2016

2015-16 were El Niño years, which adds to the general warming trend

2015

2014

2013

Extra heat from El Niño helped drive fires in the Amazon

Parts of Russia saw heat records broken by over 10ºC

2012

2011

2010

This was the hottest year on record at the time

2009

2008

2007

2006

2005

2004

Tens of thousands of deaths were attributed to a July heat wave across Europe

2003

2002

2001

Source: Copernicus ECWMF

“What matters is the long-term trend, and this is pretty much directly on trend,” Schmidt said. “That’s not going to change. Next year, I predict—just me predicting—that 2022 will be warmer than 2021. That makes it another close-to top-five year.”

NASA, NOAA, Berkeley Earth and the U.K. Met Office, which has yet to report its 2021 results, all base their analyses on global weather station and ocean data. Copernicus’s ERA5 model conducts what’s called a reanalysis of many variables and estimates its results in near-real time.

Consequences of record-breaking heat

Heat can kill in several ways, all of them preventable with cooling infrastructure. Hotter nighttime temperatures, which prevent bodies from cooling down, are sometimes linked to more deaths than daytime extremes. In June’s western North American heat wave, nighttime temperatures didn't drop in some places below 25°C (77°F). This contributed to a spike in excess deaths in British Columbia that dwarfed the mortality impact of Covid-19 that week.

Estimated excess mortality in British Columbia

There were 778 estimated excess deaths in the week following the heat wave

Excess

mortality

estimate

600

400

First wave of Covid-19 hits British Columbia

200

0

Jan

2020

July

2020

Jan

2021

July

2021

Nov

2021

There were 778 estimated excess deaths in the week following the heat wave

Excess

mortality

estimate

600

400

First wave of Covid-19 hits British Columbia

200

0

Jan

2020

July

2020

Jan

2021

July

2021

Nov

2021

There were 778 estimated excess deaths in the week following the heat wave

Excess

mortality

estimate

600

400

First wave of Covid-19 hits British Columbia

200

0

Jan

2020

July

2020

Jan

2021

July

2021

Nov

2021

Source: Statistics Canada

Erich Fischer is a climate scientist at ETH Zurich. In 2019, he and two colleagues had begun to study something they thought researchers had given too little attention: The margin by which new heat records surpass the old ones. It would be a way to complement the many analyses that compare extreme heat waves with the local normal.

They simulated heat waves in the U.S. Midwest, the site of the historic Dust Bowl. It’s a region that hasn’t notched many new heat records in decades. What they saw floored them—a leap in maximum temperature far beyond a 1-in-1,000-year event. “You basically think, OK, something went wrong,” Fischer said of the results. His colleagues agreed. Maybe an axis was mislabeled or something went haywire deep inside the model. But it all checked out.

Fischer and his partners took their results to outside researchers, some of whom accused them of potentially fear-mongering. After more work, the paper was accepted by the journal Nature Climate Change in May. Exactly four weeks later, the heat wave of unprecedented scale hit western North America, smashing records by multiple degrees. “It is exactly the type of event we had been thinking about,” he said.

Projected occurrence of record-shattering extremes in northern midlatitudes

Probability of:

3°C higher record

+50%

+25%

4.5°C higher record

6°C higher record

0

1991

2020

2050

2080

Probability of:

3°C higher record

+50%

+25%

4.5°C higher record

6°C higher record

0

1991

2020

2050

2080

Probability of:

3°C higher record

+50%

+25%

4.5°C higher record

6°C higher record

0

1991

2020

2050

2080

Source: E. M. Fischer, S. Sippel and R. Knutti, “Increasing probability of record-shattering climate extremes”, Nature Climate Change

Seemingly minor, gradual increases in global average temperatures are already bringing about disruptive weather swings. Fischer said he hopes future research will give regions a preview of what’s possible.

“It's much harder to convince people who then have to spend a lot of money on getting prepared that this is actually real and that it's plausible,” he said.