WunderBlog Archive » Category 6™
Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.Yearly, Monthly Heat Records Dissolve In 2015's Global Onslaught
The year 2015 ended in spectacular fashion, winding up as the warmest year in more than a century of recordkeeping--and it’s wasn’t even close to a photo finish. NASA and NOAA held a joint press conference on Wednesday to release their global climate assessments for the year. It had become obvious in recent weeks that 2015 was heading toward a new record high, but the final numbers were still startling. NOAA calculated that the average global temperature across both land and ocean surfaces for 2015 was 0.90°C (1.62°F) above the 20th-century average of 13.9°C (57.0°F). This makes 2015 the warmest calendar year, as well as the warmest of any 12-month period, in global temperature data going back to 1880. Using a slightly different technique, NASA confirmed that 2015 was the warmest year in this 136-year period.
The margin of 2015’s victory is itself noteworthy. NOAA calculated that 2015 beat the previous record warmth of 2014 by 0.16°C (0.29°F), which is the largest such margin for any year. NASA came up with a slightly smaller value--0.13°C (0.23°F)--which tied with 1998’s margin of victory.
Last year was the third-warmest on record for satellite-based estimates of temperature through the lowest five miles of the atmosphere, as calculated by the University of Alabama in Huntsville (UAH). Record warmth was recorded for autumn (September-November) as well as for December. Because these are indirect, large-scale estimates of temperature well above ground level, derived from satellite data, they need not correspond to trends in direct ground-based measurements of surface temperature.
Figure 1. Yearly global temperature (as expressed against the 20th-century average), 1880 - 2015. Shaded red bars indicate the average for each decade. Despite a relatively flat temperature trend in the first decade of the 2000s, global warming didn’t “stop” then. Each decade since the 1960s has been warmer than the prior one. Image credit: NASA/NOAA.
Figure 2. Departure of temperature from average for 2015, the warmest year for the globe since record keeping began in 1880. Image credit: National Centers for Environmental Information (NCEI) .
The role of El Niño
We can give El Niño credit (or blame) for part of this year’s record-smashing global temperature, but the shadow of longer-term warming due to human influence is inescapable. El Niño events tend to increase heat transfer from the ocean to atmosphere by spreading warm water across a broad stretch of the tropical Pacific, so as our climate warms, we can expect the biggest record-year spikes to occur during El Niño (as evident in Figure 2, below). That said, the huge margin of 2015’s record is comparable to the typical amount of global-scale warmth produced by a strong El Niño: several tenths of a degree Celsius. This means that 2015 may well have set a record even if El Niño were absent.
“2015 was remarkable even in the context of the ongoing El Niño,” said NASA/GISS director Gavin Schmidt. “Last year’s temperatures had an assist from El Niño, but it is the cumulative effect of the long-term trend that has resulted in the record warming that we are seeing.”
Figure 3. Departures from average in global monthly temperature from 1980 to 2015, with colors showing whether each month was characterized by El Niño (red), La Niña (blue), or neutral conditions. Image credit: NASA/NOAA.
What next?
The second year of a major El Niño tends to warm the global atmosphere even more than the first, as the atmosphere gradually adjusts to the ocean-surface warming. This means that 2016 has a very good shot at breaking the global temperature record that was just set by 2015, which in turn beat out 2014. Since records began in 1880, there have never been three consecutive record-warm years--another piece of evidence that long-term climate change is underpinning our current string of warmth. It would be exceedingly unlikely for El Niño to extend into 2017, so we might expect that year to break the string, but barring a huge volcanic eruption, the decade of the 2010s has an excellent chance of ending up warmer than the 2000s (see shaded bars in Figure 1).
The UK Met Office will soon be releasing its annual forecast of global temperature for the next decade (here’s the forecast issued in January 2015). As we discussed early last year, the now-positive state of the Pacific Decadal Oscillation suggests that we may have embarked on a decade or two of more-frequent El Niño events and accelerated atmospheric warming, similar to what occurred in the 1980s and 1990s. The PDO helps explain a good bit of the multidecadal variation in global temperature, including the slowdown in atmospheric warming evident in the 2000s and early 2010s. During these slowdowns, Earth’s oceans are taking up a larger fraction of the heat being trapped by human-produced greenhouse gases; during the speedups, the oceans are returning some of that heat to the surface. All the while, ever-increasing amounts of human-produced greenhouse gases are pushing up both the peaks and valleys of global temperature.
Earth's warmest December on record
In a fitting capstone to a sizzling year, December 2015 was the warmest calendar month in Earth’s 136-year temperature record, according to the NOAA/NCEI monthly recap released on Wednesday. December 2015 was the eighth consecutive month that a monthly high temperature record was set in NOAA's database. NASA also rated December 2015 as the single warmest calendar month in its database.
Figure 4. Departure of temperature from average for December 2015, the warmest December for the globe since record keeping began in 1880. Record warmth was observed over vast swaths of the globe, including far eastern North America, northern South America, southern Africa, and central and northern Europe, as well as most of the equatorial Indian Ocean and western North Atlantic. Image credit: National Centers for Environmental Information (NCEI) .
Arctic sea ice comes in at 4th lowest December extent on record
Arctic sea ice extent during December 2015 was the 4th lowest in the 36-year satellite record, according to the National Snow and Ice Data Center (NSIDC). An usual surge of warm air during the last week of December that brought temperatures above freezing close to the North Pole, and brought sea ice formation to a virtual halt. Arctic sea ice was close to a record minimum (for that time of year) going into 2016, possibly due to this warm surge.
Notable global heat and cold marks set for December 2015
Hottest temperature in the Northern Hemisphere: 40.6°C (105.1°F) at Armero, Columbia on December 26 and 31, and also at Guaymaral, Colombia on December 31.
Coldest temperature in the Northern Hemisphere: -63.8°C (-82.8°F) at Geo Summit, Greenland, December 16.
Hottest temperature in the Southern Hemisphere: 47.2°C (117.0°F) at Port Augusta, Australia, December 19.
Coldest temperature in the Southern Hemisphere: -43.1°C (-45.6°F) at Dome Fuji, Antarctica, December 1, and at Pole of Inaccessibility, Antarctica, December 2.
Major stations that set (not tied) new all-time heat or cold records (for any month) in December 2015
Queenstown (South Africa) max. 40.4°C 1 December
Estcourt (South Africa) max. 40.4°C 1 December
Belem (Brazil) max. 38.5°C 1 December
Caxias (Brazil) max. 42.7°C 2 December
Vryburg (South Africa) max. 42.3°C 6 December
Van Zylsrus (South Africa) max. 43.8°C 6 December
Kuruman (South Africa) max. 40.8°C 7 December
Frankfort (South Africa) max. 38.1°C 7 December
Pretoria (South Africa) max. 41.0°C 7 December
Ottosdal (South Africa) max. 42.0°C 7 December
Rustenburg (South Africa) max. 39.4°C 7 December
Bethlehem (South Africa) max. 35.6°C 7 December (revised to 36.2°C on 24 December)
Cooma (Australia) max. 39.5°C 20 December
Ladysmith (South Africa) max. 41.5°C 24 December
Richard Bay (South Africa) max. 42.7°C 24 December
Cedara (South Africa) max. 40.4°C 24 December
Pietermaritzburg (South Africa) max. 42.1°C 24 December
Tigerhoek (South Africa) max. 43.2°C 30 December
Robertson (South Africa) max. 44.8°C 30 December
Kudos go to Maximiliano Herrera for supplying the data for the "Notable global heat and cold marks set for December 2015" and "Major stations that set (not tied) new all-time heat or cold records in December 2015" sections of the post.
Coming up: full coverage of the big mid-Atlantic snowstorm
We’ll have a full update Thursday afternoon on the mammoth winter storm that will be developing from the central Appalachians onward to the East Coast over the next several days. Computer models remain insistent that snow amounts of 15-25” are quite possible over large parts of Virginia, West Virginia, Maryland, and the District of Columbia. High-impact snows may extend further north, but the uncertainty there is greater, and the amounts should drop off rapidly toward the north edge of the storm (see embedded tweet below for one forecaster’s unofficial take). If you are in the targeted areas, now is the time to make any needed preparations. To find out the odds that a given amount of snow will fall in your area, check out the innovative probabilistic maps being generated by the NWS offices serving the Baltimore-Washington and New York City areas. We’ll be covering the storm with a WU liveblog on Friday and Saturday; watch for details.
Jeff Masters and Bob Henson
The margin of 2015’s victory is itself noteworthy. NOAA calculated that 2015 beat the previous record warmth of 2014 by 0.16°C (0.29°F), which is the largest such margin for any year. NASA came up with a slightly smaller value--0.13°C (0.23°F)--which tied with 1998’s margin of victory.
Last year was the third-warmest on record for satellite-based estimates of temperature through the lowest five miles of the atmosphere, as calculated by the University of Alabama in Huntsville (UAH). Record warmth was recorded for autumn (September-November) as well as for December. Because these are indirect, large-scale estimates of temperature well above ground level, derived from satellite data, they need not correspond to trends in direct ground-based measurements of surface temperature.
Figure 1. Yearly global temperature (as expressed against the 20th-century average), 1880 - 2015. Shaded red bars indicate the average for each decade. Despite a relatively flat temperature trend in the first decade of the 2000s, global warming didn’t “stop” then. Each decade since the 1960s has been warmer than the prior one. Image credit: NASA/NOAA.
Figure 2. Departure of temperature from average for 2015, the warmest year for the globe since record keeping began in 1880. Image credit: National Centers for Environmental Information (NCEI) .
The role of El Niño
We can give El Niño credit (or blame) for part of this year’s record-smashing global temperature, but the shadow of longer-term warming due to human influence is inescapable. El Niño events tend to increase heat transfer from the ocean to atmosphere by spreading warm water across a broad stretch of the tropical Pacific, so as our climate warms, we can expect the biggest record-year spikes to occur during El Niño (as evident in Figure 2, below). That said, the huge margin of 2015’s record is comparable to the typical amount of global-scale warmth produced by a strong El Niño: several tenths of a degree Celsius. This means that 2015 may well have set a record even if El Niño were absent.
“2015 was remarkable even in the context of the ongoing El Niño,” said NASA/GISS director Gavin Schmidt. “Last year’s temperatures had an assist from El Niño, but it is the cumulative effect of the long-term trend that has resulted in the record warming that we are seeing.”
Figure 3. Departures from average in global monthly temperature from 1980 to 2015, with colors showing whether each month was characterized by El Niño (red), La Niña (blue), or neutral conditions. Image credit: NASA/NOAA.
What next?
The second year of a major El Niño tends to warm the global atmosphere even more than the first, as the atmosphere gradually adjusts to the ocean-surface warming. This means that 2016 has a very good shot at breaking the global temperature record that was just set by 2015, which in turn beat out 2014. Since records began in 1880, there have never been three consecutive record-warm years--another piece of evidence that long-term climate change is underpinning our current string of warmth. It would be exceedingly unlikely for El Niño to extend into 2017, so we might expect that year to break the string, but barring a huge volcanic eruption, the decade of the 2010s has an excellent chance of ending up warmer than the 2000s (see shaded bars in Figure 1).
The UK Met Office will soon be releasing its annual forecast of global temperature for the next decade (here’s the forecast issued in January 2015). As we discussed early last year, the now-positive state of the Pacific Decadal Oscillation suggests that we may have embarked on a decade or two of more-frequent El Niño events and accelerated atmospheric warming, similar to what occurred in the 1980s and 1990s. The PDO helps explain a good bit of the multidecadal variation in global temperature, including the slowdown in atmospheric warming evident in the 2000s and early 2010s. During these slowdowns, Earth’s oceans are taking up a larger fraction of the heat being trapped by human-produced greenhouse gases; during the speedups, the oceans are returning some of that heat to the surface. All the while, ever-increasing amounts of human-produced greenhouse gases are pushing up both the peaks and valleys of global temperature.
Earth's warmest December on record
In a fitting capstone to a sizzling year, December 2015 was the warmest calendar month in Earth’s 136-year temperature record, according to the NOAA/NCEI monthly recap released on Wednesday. December 2015 was the eighth consecutive month that a monthly high temperature record was set in NOAA's database. NASA also rated December 2015 as the single warmest calendar month in its database.
Figure 4. Departure of temperature from average for December 2015, the warmest December for the globe since record keeping began in 1880. Record warmth was observed over vast swaths of the globe, including far eastern North America, northern South America, southern Africa, and central and northern Europe, as well as most of the equatorial Indian Ocean and western North Atlantic. Image credit: National Centers for Environmental Information (NCEI) .
Arctic sea ice comes in at 4th lowest December extent on record
Arctic sea ice extent during December 2015 was the 4th lowest in the 36-year satellite record, according to the National Snow and Ice Data Center (NSIDC). An usual surge of warm air during the last week of December that brought temperatures above freezing close to the North Pole, and brought sea ice formation to a virtual halt. Arctic sea ice was close to a record minimum (for that time of year) going into 2016, possibly due to this warm surge.
Notable global heat and cold marks set for December 2015
Hottest temperature in the Northern Hemisphere: 40.6°C (105.1°F) at Armero, Columbia on December 26 and 31, and also at Guaymaral, Colombia on December 31.
Coldest temperature in the Northern Hemisphere: -63.8°C (-82.8°F) at Geo Summit, Greenland, December 16.
Hottest temperature in the Southern Hemisphere: 47.2°C (117.0°F) at Port Augusta, Australia, December 19.
Coldest temperature in the Southern Hemisphere: -43.1°C (-45.6°F) at Dome Fuji, Antarctica, December 1, and at Pole of Inaccessibility, Antarctica, December 2.
Major stations that set (not tied) new all-time heat or cold records (for any month) in December 2015
Queenstown (South Africa) max. 40.4°C 1 December
Estcourt (South Africa) max. 40.4°C 1 December
Belem (Brazil) max. 38.5°C 1 December
Caxias (Brazil) max. 42.7°C 2 December
Vryburg (South Africa) max. 42.3°C 6 December
Van Zylsrus (South Africa) max. 43.8°C 6 December
Kuruman (South Africa) max. 40.8°C 7 December
Frankfort (South Africa) max. 38.1°C 7 December
Pretoria (South Africa) max. 41.0°C 7 December
Ottosdal (South Africa) max. 42.0°C 7 December
Rustenburg (South Africa) max. 39.4°C 7 December
Bethlehem (South Africa) max. 35.6°C 7 December (revised to 36.2°C on 24 December)
Cooma (Australia) max. 39.5°C 20 December
Ladysmith (South Africa) max. 41.5°C 24 December
Richard Bay (South Africa) max. 42.7°C 24 December
Cedara (South Africa) max. 40.4°C 24 December
Pietermaritzburg (South Africa) max. 42.1°C 24 December
Tigerhoek (South Africa) max. 43.2°C 30 December
Robertson (South Africa) max. 44.8°C 30 December
Kudos go to Maximiliano Herrera for supplying the data for the "Notable global heat and cold marks set for December 2015" and "Major stations that set (not tied) new all-time heat or cold records in December 2015" sections of the post.
Coming up: full coverage of the big mid-Atlantic snowstorm
We’ll have a full update Thursday afternoon on the mammoth winter storm that will be developing from the central Appalachians onward to the East Coast over the next several days. Computer models remain insistent that snow amounts of 15-25” are quite possible over large parts of Virginia, West Virginia, Maryland, and the District of Columbia. High-impact snows may extend further north, but the uncertainty there is greater, and the amounts should drop off rapidly toward the north edge of the storm (see embedded tweet below for one forecaster’s unofficial take). If you are in the targeted areas, now is the time to make any needed preparations. To find out the odds that a given amount of snow will fall in your area, check out the innovative probabilistic maps being generated by the NWS offices serving the Baltimore-Washington and New York City areas. We’ll be covering the storm with a WU liveblog on Friday and Saturday; watch for details.
Jeff Masters and Bob Henson
I joined the snow map parade because I can. Just my own $0.02. Read my thinking here: https://t.co/kUtYe3tTgS pic.twitter.com/vv2sXlv9wM
— Matt Lanza (@mattlanza) January 20, 2016Climate Change Climate Summaries
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.