August Extends an Exceptional String of Record-Warm Global Months

August 2016 was Earth's warmest August since record keeping began in 1880, said NOAA's National Centers for Environmental Information (NCEI) on Tuesday. In the NOAA database, August 2016 came in 0.92°C (1.66°F) warmer than the 20th-century average for August, beating the previous record for August, set in 2015, by 0.05°C. NASA also reported the warmest August in its database, as well as a tie with July 2016 for the warmest absolute temperature recorded in any month. Because most of the world’s land area is in the Northern Hemisphere, absolute global temperatures are warmest in northern summer--about 3-4°C (5-7°F) higher than in northern winter. This is why monthly global anomalies (departures from the monthly average) are commonly used to assess the relative warmth or coolness of a given month.


Figure 1. The departure from average (compared to temperatures from 1980 - 2015) of Earth’s surface temperature from 1880 to 2016, with the seasonal cycle left in. July and August 2016 were Earth’s hottest months on record in absolute terms, while February 2016 had the largest departure from average (in relative terms) from average of any month in the historical record. Image credit: Gavin Schmidt, director of NASA’s Goddard Institute of Space Studies.


Figure 2. Departure of temperature from average for August 2016, the warmest August for the globe since record keeping began in 1880. Pockets of record warmth were observed across every major ocean basin, including the northwest Atlantic, and over a few land areas. Image credit: National Centers for Environmental Information (NCEI).

A year-plus streak of global records
August 2016 marked the 16th consecutive month that NOAA’s global monthly temperature record was broken, which is the longest such streak since global temperature records began in 1880. Ocean-only temperatures were 0.02°C (0.04°F) cooler than the record warmth of August 2015, while land-only temperatures were a substantial 0.19°C (0.34°F) above the previous land-only record from August 2015. For the lowest 8 km of the atmosphere, global satellite-measured temperatures in August 2016 were the second warmest for any August in the 38-year record, behind only 1998, according to the University of Alabama in Huntsville (UAH).

With the powerful 2015-16 El Niño event now over, the impressive global warmth in recent months can mostly be attributed to the steady build-up of heat-trapping greenhouse gases due to human activities. NOAA’s global surface temperature for the year so far (January-August 2016) is an eye-opening 1.01°C (1.82°F) above the 20th-century average and a remarkable 0.16°C (0.29°F) warmer than the previous January-to-August record, set in 2015 (see Figure 3 below).

Following the 1997-98 “super” El Niño, monthly global temperature records were set through August 1998. The departure of the equally strong 2015-16 El Niño and the possible arrival of La Niña late this year should allow temperatures to drop slightly, perhaps breaking our string of record-warm months sometime in the near future. However, temperatures would have to truly plummet between now and December in order to keep 2016 from becoming the warmest year in global record-keeping. Gavin Schmidt, director of NASA’s Goddard Institute of Space Studies, maintains that we have a better-than-99 percent chance of 2016 ending up as Earth’s third consecutive hottest year on record. Last week, in an essay for fivethirtyeight.com, Schmidt explained how he and his colleagues gained early confidence on that 2016 would be a record-warm year, based largely on the presence of the strong El Niño late last year. “Some key climate statistics are easily predictable far beyond the scales at which weather forecasts are skillful,” Schmidt wrote. “Those predictions clearly suggest an annual global temperature record in 2016 and a (relative) cooling in 2017, all while the long-term upward trends continue.”


Figure 3. Departure from the 20th-century average for the global January-through-August temperature for the years 1880 - 2016. This year has seen by far the warmest temperatures on record for the year-to-date period. Image credit: NOAA/National Centers for Environmental Information (NCEI).

NOAA no longer expects a La Niña event
Sea surface temperatures in the Niño3.4 monitoring region of the eastern Pacific have been hovering near the threshold for a weak La Niña over the last couple of months. However, the atmospheric conditions that normally accompany La Niña have not fully evolved, and models suggest they may continue to lag. For this reason, NOAA has dropped the La Niña Watch that was in place for several months. According to the September ENSO forecast from NOAA’s Climate Prediction Center, neutral conditions are favored to persist through the Northern Hemisphere fall and into the winter (55 - 60% chance), with La Niña given about a 40% chance. This is a marked shift from NOAA’s August forecast, which called for a 55 - 60% chance of a La Niña event. Other agencies around the world are somewhat more bullish on La Niña, as noted by Climate Central’s John Upton last week. Australia’s Bureau of Meteorology retained its La Niña watch in its biweekly update on September 13, “Some climate models indicate a late and weak La Niña is possible,” the update noted. (Australia’s oceanic threshold for La Niña and El Niño is higher than NOAA’s: the Niño3.4 region must be at least 0.8°C warmer or cooler than average, rather than 0.5°C, though Australia doesn’t require those temperatures to persist for months as NOAA does.) The Japan Meteorological Agency has gone further: “It is considered that La Niña conditions are present in the equatorial Pacific,” stated the agency in its monthly update on September 9. The JMA uses the Niño3 region, which overlaps with the Niño3.4 region but extends further east.

Arctic sea ice hits its fourth lowest August extent on record
The rate of August sea ice loss was below average last month, due to cool and stormy conditions in the Arctic. As a result, sea ice extent in August 2016 was just the fourth lowest in the 38-year satellite record, according to the National Snow and Ice Data Center (NSIDC). So far, March, July and August have been the only months in 2016 that did not set a new record low for Arctic-wide sea ice extent (March 2016 was second lowest, July was third lowest). As we reported here last week, the annual minimum in sea ice occurred last week, and was statistically tied for the second lowest extent on record.

Three billion-dollar weather disasters for August 2016: Louisiana floods, China drought, U.S. severe weather
According to the August 2016 Catastrophe Report from insurance broker Aon Benfield, two billion-dollar weather-related disaster hit the planet in August: a disastrous $10 - $15 billion flood in Louisiana, and a drought in China that cost $1.6 billion. Additionally, a severe weather outbreak in the Plains and Rockies on July 28 - 29 accumulated enough damage claims to be rated a billion-dollar disaster by the end of August. Between January - August 2016, there were 24 billion-dollar weather disasters globally--four fewer than occurred during January - August 2013, the year that ended up with the most billion-dollar weather disasters on record: 41. Here is the tally of billion-dollar weather disasters for January - August 2016:

1) Flooding, Yangtze Basin, China, 5/1 - 8/1, $28.0 billion, 475 killed
2) Flooding, Louisiana (U.S.), 8/9 - 8/16, $10 - $15 Billion, 13 killed
3) Flooding, Germany, France, Austria, Poland, 5/26 - 6/6, $5.5 billion, 17 killed
4) Drought, India, 1/1 - 6/30, $5.0 billion, 0 killed
5) Flooding, Northeast China 7/16 - 7/24, $5.0 billion, 289 killed
6) Wildfire, Fort McMurray, Canada, 5/2- 6/1, $5.0 billion, 0 killed
7) Severe Weather, Plains-Southeast U.S., 4/10 - 4/13, $3.75 billion, 1 killed
8) Severe Weather, Rockies-Plains-Southeast-Midwest U.S., 3/22 - 3/25, $2.5 billion, 0 killed
9) Flooding, China, 6/18 - 6/23, $2.3 billion, 68 killed
10) Winter Weather, East Asia, 1/20 - 1/26, $2.0 billion, 116 killed
11) Tropical Cyclone Roanu, Sri Lanka, India, Bangladesh, Myanmar, China, 5/14 - 5/21, $1.7 billion, 135 killed
12) Severe Weather, Plains-Midwest U.S., 4/29 - 5/3, $1.6 billion, 6 killed
13) Drought, China, 1/1 - 3/1, $1.6 billion, 0 killed
14) Drought, Zimbabwe, 6/1 - 8/10, $1.6 billion, 0 killed
15) Severe Weather, Plains-Midwest-Southeast-Northeast U.S., 3/4 - 3/12, $1.5 billion, 6 killed
16) Typhoon Nepartak, Philippines, Taiwan, China, 7/8 - 7/9, $1.5 billion, 111 killed
17) Severe Weather, Plains-Southeast U.S., 3/17 - 3/18, $1.4 billion, 0 killed
18) Flooding, Argentina and Uruguay, 4/4 - 4/10, $1.3 billion, 0 killed
19) Severe Weather, Plains-Midwest-Southeast-Northeast U.S., 2/22 - 2/25, $1.2 billion, 10 killed
20) Severe Weather, Plains-Midwest U.S., 5/21 - 5/28, $1.1 billion, 1 killed
21) Severe Weather, Netherlands, 6/23 - 6/24, $1.1 billion, 0 killed
22) Severe Weather, Plains-Rockies U.S., 7/28 - 7/29, $1.0 billion, 0 killed
23) Tropical Cyclone Winston, Fiji, 2/16 - 2/22, $1.0 billion, 44 killed
24) Winter Weather, Eastern U.S., 1/21 - 1/24, $1.0 billion, 58 killed


And here are the three disasters from August 2016 in more detail:


Disaster 1. Torrential rains of 20 - 30” fell over portions of Louisiana August 9 - 16 from a tropical depression-like storm that meandered over the southern U.S. for a week. Catastrophic flooding killed thirteen people, and damaged as many 110,000 homes and 100,000 vehicles. Damage was estimated at $10 - $15 billion, which will likely make it the second most expensive non-hurricane related flood in U.S. history, behind the $35 billion in damage from the summer 1993 flooding in the Midwest. In this image, we see an aerial view of flooding in Hammond, Louisiana on August 13, 2016. AP Photo/Max Becherer.


Disaster 2. Severe drought began in June across northeastern China in the Inner Mongolia, Jilin and Heilongjiang provinces, and intensified during August. The Ministry of Civil Affairs (MCA) reported well-above normal temperatures and reduced rainfall that damaged more than 3.1 million hectares (7.6 million acres), with total economic losses at $1.6 billion. In this image, we see drought conditions in China as of September 1, 2016. Image credit: Beijing Climate Center.


Disaster 3. Severe thunderstorms swept across parts of the Rockies and Plains on July 28 - 29, causing $1 billion in damage. Hardest hit was Colorado, where golf-ball-and-larger-sized hail struck the Colorado Springs metro area. Hail accumulations up to one feet (0.3 meters) fell in some areas, and torrential rains led to flash flooding. Heavy losses were also reported in Wyoming, Kansas, Nebraska, and South Dakota. In this image, we see an intense thunderstorm building over Boulder, Colorado on July 29, 2016. Image credit: wunderphotographer austncitylimits.

Below-average monsoon rains cause deadly flooding in India
India, whose $5 billion drought has been Earth's fourth most expensive weather-related natural disaster of 2016, is getting a better monsoon after two straight years of poor rains, but the moisture delivered to date is still below average. According to the India Meteorological Department, monsoon rains during the period June 1 - September 19, 2016 were about 5% below average. Even a below-average Indian monsoon can still wreak havoc through flooding. Through the end of August, monsoon floods had killed at least 510 people in India and caused at least $150 million in damage, with the Ganges River reaching the highest levels ever recorded at four locations in northern India. Worst affected were the states of Rajasthan, Maharashtra, Assam, Bihar, Uttar Pradesh, West Bengal, and Jharkhand.

Notable global heat and cold marks set in August 2016
Hottest temperature in the Northern Hemisphere: 52.7°C (126.9°F) at Mitribah, Kuwait, 2 August
Coldest temperature in the Northern Hemisphere: -32.4°C (-26.3°F) at Geo Summit, Greenland, 15 August
Hottest temperature in the Southern Hemisphere: 41.7°C (107.1°F) at Palmas, Brazil, 18 August
Coldest temperature in the Southern Hemisphere: -78.1°C (-108.6°F) at Vostok, Antarctica, 31 August
(Courtesy of Maximiliano Herrera.)

Major weather stations that set (not tied) new all-time heat or cold records in August 2016 (Courtesy of Maximiliano Herrera)
Erdeni (Mongolia) max. 40.5°C, 1 August
Bayandelger (Mongolia) max. 39.4°C, 2 August
Choibalsan (Mongolia) max. 41.9°C, 3 August
Khalkh Gol (Mongolia) max. 41.7°C, 3 August
Dashbalbar (Mongolia) max. 41.4°C, 3 August
Matad (Mongolia) max.  40.7°C,  3 August
Xin Barag Youqi (China) max. 44.1°C, 3 August
Hailar (China) max. 41.7°C, 3 August
Uliastai (China) max. 40.6°C, 3 August; increased to 42.5 on 4 August
Arxan (China) max. 37.6°C, 3 August; increased to 39.1 on 4 August
Kajlastuj (Russia) max. 41.6°C, 3 August
Dubai Airport (United Arab Emirates) max. 48.9°C, 3 August
Xilin Hot (China) max. 39.8°C, 4 August
Hyesan (North Korea) max. 39.7°C, 5 August
Samjiyon (North Korea) max. 32.2°C, 5 August
Vigo (Spain) max. 40.8°C, 7 August
Braga (Portugal) max. 42.2°C, 7 August
Porto City (Portugal) max. 40.9°C,  7 August
Porto Airport (Portugal) max. 38.6°C, 7 August
Mora (Portugal) max. 44.8°C,   7 August
Kyowa (Japan) max. 33.6°C, 7 August
Mishima (Japan) max. 37.2°C, 8 August; increased to 37.4°C on 9 August
Waki (Japan) max. 37.9°C, 8 August
Kiriishi  (Japan) max. 39.2°C, 9 August
Nanbu  (Japan) max. 38.9°C, 9 August
Gotemba  (Japan) max. 35.3°C, 9 August
Kikukawa Makinohara  (Japan) max.  37.0°C, 9 August
Angra do Heroismo (Azores, Portugal) max. 29.3°C, 9 August
Omuta (Japan) max. 37.5°C, 11 August
Imari (Japan) max. 36.9°C, 11 August
Aso Otohime  (Japan) max. 34.9°C, 11 August
Aso (Japan) max. 29.8°C, 11 August
Haenam (South Korea) max. 37.1°C, 11 August
Chizu (Japan) max. 37.0°C, 12 August
Ureshino (Japan) max. 38.5°C, 12 August
Izuhara (Japan) max. 36.8°C, 13 August
Gyeongju (South Korea) max. 39.4°C, 12 August
Youngcheon (South Korea) max. 39.6°C, 13 August
Yeongdeok (South Korea) max. 38.6°C, 13 August
Pohang (South Korea) max. 39.3°C, 13 August
Busan (South Korea) max. 37.3°C, 14 August
Hinatuan (Philippines) max. 37.2°C, 19 August
Owen Int. Airport (Cayman Islands, United Kingdom) max. 34.9°C, 21 August *
Ikuchishima (Japan) max. 36.3°C, 21 August
Aki (Japan) max. 36.5°C, 21 August
Sendai (Japan) max. 37.2°C, 21 August
Kiinagashima (Japan) max. 37.9°C, 22 August  
Shingu (Japan) max. 38.4°C, 22 August
Kagoshima (Japan) max. 37.4°C, 22 August
Kiire (Japan) max. 37.4°C, 22 August
Kimotsuki Maeda (Japan) max. 36.7°C, 22 August  
Makurazaki (Japan) max. 36.7°C, 22 August
Koniya (Japan) max. 34.4°C, 23 August
Fengjie (China) max. 42.2°C, 24 August
Utirik Atoll (Marshall Islands) max. 35.6°C, 24 August **
Neijiang (China) max. 40.1°C, 25 August
North Lakimpur (India) max. 39.9°C, 25 August
Cape Arkona (Germany) max. 32.2°C, 26 August


Notes from Maximiliano Herrera:
* ties the territorial record for the highest temperature ever recorded in the Cayman Islands
** breaks the territorial record for the highest temperature ever recorded in the Marshall Islands

Two all-time national heat records set or tied in August 2016
Two nations or territories--the Cayman Islands and the Marshall Islands--set or tied records in August 2016 for their all-time hottest temperature on record. Update (25 September]: From January through September 10, 2016, a total of 21 nations or territories tied or set all-time records for their hottest temperature in recorded history, including the British Virgin Islands record just added below. This breaks the record of eighteen all-time heat records set in 2010 for the greatest number of such records set in one year. Also, one all-time cold temperature record has been set so far in 2016 (in Hong Kong.) "All-time" record here refers to the warmest or coldest temperature ever reliably reported in a nation or territory. The period of record varies from country to country and station to station, but it is typically a few decades to a century or more. Most nations do not maintain official databases of extreme temperature records, so the national temperature records reported here are in many cases not official. Our data source is international weather records researcher Maximiliano Herrera, one of the world's top climatologists, who maintains a comprehensive list of extreme temperature records for every nation in the world on his website. If you reproduce this list of extremes, please cite Maximiliano Herrera as the primary source of the weather records. Here are 2016's all-time heat and cold records as of September  10:

French Guiana tied its all-time hottest record on September 10, 2016, when the mercury hit 37.9°C (100.2°F) at Saint Laurent do Moroni.

The Marshall Islands set its all-time hottest record on August 24, 2016, when the mercury hit 35.6°C (96.1°F) at Utirik Atoll.

The Cayman Islands (United Kingdom territory) tied its all-time hottest record on August 21, 2016, when the mercury hit 34.9°C (94.8°F) at Owen International Airport.

The British Virgin Islands [United Kingdom territory] set its all-time hottest record on July 22, 2016, when the mercury hit 35.0°C (95.0°F] at Terrance B. Lettsome International Airport.

Iraq set its all-time hottest record on July 22, 2016, when the mercury hit 53.9°C (129.0°F) at Basrah.

Iran tied its all-time hottest record on July 22, 2016, when the mercury hit 53.0°C (127.4°F) at Delhoran.

Kuwait set its all-time hottest record on July 21, 2016, when the mercury hit 54.0°C (129.2°F) at Mitribah.

Guernsey (United Kingdom territory) tied its all-time hottest record on July 19, 2016, when the mercury hit 35.0°C (95°F) at the small island of Alderney.

Hong Kong Territory (China) tied its all-time hottest record on July 9, 2016, when the mercury hit 37.9°C (100.2°F) at Happy Valley.

Niger set its all-time hottest record on June 8, 2016, when the mercury hit 49.0°C (120.2°F) at Bilma.

Palau tied its all-time hottest record on June 8, 2016, when the mercury hit 34.4°C (93.9°F) at Koror AWS.

India set its all-time hottest record on May 19, 2016, when the mercury hit 51.0°C (123.8°F) at Phalodi.

Maldives set its all-time hottest record on April 30, 2016, when the mercury hit 35.0°C (95.0°F) at Hanimaadhoo.

Thailand set its all-time hottest record on April 28, 2016, when the mercury hit 44.6°C (112.3°F) at Mae Hong Son.

Cambodia set its all-time hottest record on April 15, 2016, when the mercury hit 42.6°C (108.7°F) at Preah Vihea.

Burkina Faso set its all-time hottest record on April 13, 2016, when the mercury hit 47.5°C (117.5°F) at Dori.

Laos set its all-time hottest record on April 12, 2016, when the mercury hit 42.3°C (108.1°F) at Seno.

Vanuatu in the South Pacific set its all-time hottest record on February 8, 2016, when the mercury hit 36.2°C (97.2°F) at Lamap Malekula.

Tonga set its all-time hottest record on February 1, 2016, when the mercury hit 35.5°C (95.9°F) at Niuafoou.

Wallis and Futuna Territory (France) set a new territorial heat record with 35.8°C (96.4°F) on January 10, 2016 at Futuna Airport. This is the second year in a row that Wallis and Futuna has beaten its all-time heat mark; the previous record was a 35.5°C (95.9°F) reading on January 19, 2015 at the Futuna Airport.

Botswana set its all-time hottest record on January 7, 2016, when the mercury hit 43.8°C (110.8°F) at Maun.

Hong Kong Territory (China) set its all-time coldest mark on January 24, 2016, when the mercury dipped to -6.0°C (21.2°F) at Tai Mo Shan.

We'll be back on Thursday with the latest on tropical activity in the Atlantic and Pacific (see also our update from Wednesday morning].

Jeff Masters and Bob Henson