Comparison of surface albedos derived from spaceborne radiometers with different spectral bands requires, first of all, the conversion of these quanti…Comparison of surface albedos derived from spaceborne radiometers with different spectral bands requires, first of all, the conversion of these quantities into common spectral intervals. This letter proposes a spectral conversion method specifically dedicated to surface albedo derived in a large-band instrument such as the solar channel onboard the Meteosat first-generation radiometer. This new method accounts for the retrieval algorithm assumptions and radiometer spectral limitations that might have an impact on the retrieved surface albedo in such a large band. It is also shown that the proposed approach has no impact when surface albedo is derived in narrow bands and confirms the results of previously published spectral conversion methods.more
Editors note: For easy download the posted pdf of the State of the Climate for 2014 is a very low-resolution file. A high-resolution copy of the repor…Editors note: For easy download the posted pdf of the State of the Climate for 2014 is a very low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.more
Editor’s note: For easy download the posted pdf of the State of the Climate for 2016 is a very low-resolution file. A high-resolution copy of the repo…Editor’s note: For easy download the posted pdf of the State of the Climate for 2016 is a very low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.more
Abstract
Editor’s note: For easy download the posted pdf of the State of the Climate for 2017 is a low-resolution file. A high-resolution …Abstract
Editor’s note: For easy download the posted pdf of the State of the Climate for 2017 is a low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.more
Abstract
Editor’s note: For easy download the posted pdf of the State of the Climate for 2018 is a low-resolution file. A high-resolution …Abstract
Editor’s note: For easy download the posted pdf of the State of the Climate for 2018 is a low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.more
In 2019, the dominant greenhouse gases released into Earth’s atmosphere continued to increase. The annual global average carbon diox…In 2019, the dominant greenhouse gases released into Earth’s atmosphere continued to increase. The annual global average carbon dioxide concentration at Earth’s surface was 409.8 ± 0.1 ppm, an increase of 2.5 ± 0.1 ppm over 2018, and the highest in the modern instrumental record and in ice core records dating back 800000 years. Combined, greenhouse gases and several halogenated gases contributed 3.14 W m−2to radiative forcing, representing a 45% increase since 1990. Carbon dioxide is responsible for about 65% of this radiative forcing. The annual net global uptake of ~2.4 billion metric tons of carbon dioxide by oceans was the highest in the record dating to 1982 and 33% higher than the 1997–2017 average.A weak El Niño at the beginning of 2019 transitioned to ENSO-neutral conditions by mid-year. Even so, the annual global surface temperature across land and oceans was still among the three highest in records dating to the mid- to late 1800s. July 2019 was Earth’s hottest month on record.
Well over a dozen countries across Africa, Europe, Asia, Australia, and the Caribbean reported record high annual temperatures. In North America, Alaska experienced its warmest year on record, while the high northern latitudes that encompass the Arctic were second warmest, behind only 2016. Stations in several countries, including Vietnam, the Netherlands, Belgium, Luxembourg, France, and the United Kingdom, set new all-time daily high temperature records for their nations. Australia set a new nationally averaged daily maximum temperature record of 41.9°C on 18 December, breaking the previous record set in 2013 by 1.6°C. Daily temperatures surpassed 40°C for the first time in Belgium and the Netherlands. Lake temperatures increased on average across the globe in 2019; observed lakes in the Northern Hemisphere were covered in ice seven days fewer than the 1981–2010 average, according to phenological indicators. Over land, the growing season was an average of eight days longer than the 2000–10 average in the NH.Above Earth’s surface, the annual lower troposphere tem-perature was third highest to record high, and the lower strato-sphere temperature was third lowest to record low, depending on the dataset analyzed. Middle- and upper-stratospheric temperatures were lowest on record since satellite records be-gan in 1979. In September, Antarctica experienced a dramatic upper-atmosphere warming event that led to the smallest ozone hole since the early 1980s. Below-average Antarctic sea ice extent persisted throughout 2019, continuing a trend that began in September 2016. Net sea ice extent was below the 1981–2010 average for all days of the year, and January and June each set a new low monthly mean sea ice extent record.
The Antarctic ice sheet continued to lose mass, with the highest rates of loss occurring in West Antarctica and Wilkes Land, East Antarctica. Across the cryosphere, alpine glaciers continued to lose mass for the 32nd consecutive year. Permafrost temperatures in the European Alps were slightly below the record temperatures measured in 2015, while record high permafrost temperatures were observed at a majority of the observation sites across the high northern latitudes. For the first time in the observational record at 26 sites in interior Alaska and the Seward Peninsula, the active layer did not freeze completely, a result of long-term permafrost warming and back-to-back relatively mild and snowy winters.In March, when Arctic sea ice reached its annual maximum extent, thin, first-year ice comprised ~77% of all ice, compared to about 55% in the 1980s.
In September, the minimum sea ice extent tied for the second smallest extent in the 41-year satel-lite record. In the Bering Sea, increasing ocean temperatures and reduced sea ice—which was the lowest on record there for the second consecutive winter—are leading to shifts in fish distributions within some of the most valuable fisheries in the world. Larger and more abundant boreal species, as opposed to smaller and less abundant Arctic species, dominated a large portion of the Arctic shelf in 2018 and 2019. During the 2019 melt season, the extent and magnitude of ice loss over the Greenland ice sheet rivaled 2012, the previous year of record ice loss. Melting of glaciers and ice sheets, along with warming oceans, account for the trend in rising global mean sea level. In 2019, global mean sea level set a new record for the eighth consecutive year, reaching 87.6 mm above the 1993 average when satellite measurements began, with an annual average increase of 6.1 mm from 2018. Ocean heat content measured to 700 m depth was record high, and the globally averaged sea surface temperature was the second highest on record, surpassed only by the record El Niño year of 2016.
In October, the Indian Ocean dipole exhibited its greatest magnitude since 1997, associated with dramatic upper ocean warming in the western Indian Ocean basin. While ENSO conditions during 2019 appeared to have limited impacts, many climate events were influenced by the strong positive IOD, which contributed to a large rainfall deficit from the eastern Indian Ocean to the South Pacific Ocean east of Australia. Record heat and dryness in Australia intensified drought conditions already in place following below-average rainfall in 2017 and 2018, leading to severe impacts during late austral spring and summer, including catastrophic wildfires.
Smoke from these wildfires, along with the volcanic eruptions of Raikoke (Russia) and Ulawun (Papua New Guinea), helped load the stratosphere with aerosol levels unprecedented since the post-Mt. Pinatubo era of the early 1990s. Indonesia also suffered severe drought and extreme wildfires toward the end of 2019; no rainfall was observed in the East Sumba District of the East Nusa Tenggara Province for 263 days.Conversely, the positive IOD also contributed to excess rainfall over the Horn of Africa from August through December, resulting in widespread flooding across East Africa.
Elsewhere, India experienced one of its heaviest summer monsoon rains since 1995 despite a delayed and suppressed monsoon during June. In the United States, rapid snowmelt in the spring, as well as heavy and frequent precipitation in the first half of the year, contributed to extensive flooding in the Midwest throughout spring and summer, notably the Mississippi and Missouri basins. Dry conditions persisted over large parts of western South Africa, in some locations having continued for approximately seven years. Antecedent dry conditions and extreme summer heat waves pushed most of Europe into extreme drought. Due in part to precipitation deficits during December 2018 to January 2019—the peak of the rainy season—wildfires scorched vast areas of the southern Amazonian forests in Bolivia, Brazil, and Peru, as well as in northern Paraguay, later in 2019.
Millions of trees and animals perished, with some local extinctions reported. In Siberia, fire activity during the sum-mer was both strong and farther north than usual. This led to a new record of 27 teragrams (1012 g) of carbon emitted from fires in the Arctic, which was more than twice as high than in any preceding year. Closer to the equator, 96 named tropical storms were ob-served during the Northern and Southern Hemisphere storm seasons, well above the 1981–2010 average of 82. Five tropical cyclones reached Saffir–Simpson scale Category 5 intensity. In the North Atlantic basin, Hurricane Dorian caused unprec-edented and tremendous devastation, with over 70 fatalities and damages totaling $3.4 billion (U.S. dollars) in The Bahamas. Tropical Cyclones Idai and Kenneth severely impacted south-eastern Africa in March and April, respectively. Idai resulted in total damages of at least $2.2 billion (U.S. dollars), the costli-est storm on record for the South Indian Ocean basin, as well as the deadliest with over 1200 fatalities across Mozambique, Zimbabwe, Malawi, and Madagascar.more
In 2020, the dominant greenhouse gases stored in Earth’s atmosphere continued to increase. The annual global average carbon dioxide (CO2) concentratio…In 2020, the dominant greenhouse gases stored in Earth’s atmosphere continued to increase. The annual global average carbon dioxide (CO2) concentration at Earth’s surface was 412.5 ± 0.1 ppm, an increase of 2.5 ± 0.1 ppm over 2019, and the high-est in the modern instrumental record and in ice core records dating back 800,000 years. While anthropogenic CO2 emissions were estimated to decrease around 6%–7% globally during the year due to reduced human activities during the COVID-19 pan-demic, the reduction did not materially affect atmospheric CO2accumulation as it is a relatively small change, less even than interannual variability driven by the terrestrial biosphere. The net global uptake of ~3.0 petagrams of anthropogenic carbon by oceans in 2020 was the highest in the 39-year record and almost 30% higher than the 1999–2019 average. Weak El Niño-like conditions in the eastern equatorial Pacific Ocean in early 2020 cooled and transitioned to a moderate La Niña later in the year. Even so, the annual global surface tem-perature across land and oceans was among the three highest in records dating to the mid- to late 1800s.
In Europe, 17 countries reported record high annual mean temperatures, contributing to the warmest year on record for the European continent. Elsewhere, Japan, Mexico, and Seychelles also experienced re-cord high annual mean temperatures. In the Caribbean, Aruba, Martinique, and St. Lucia reported their all-time monthly maximum temperatures. In the United States, Furnace Creek in Death Valley, California, reached 54.4°C on 16 August—the hottest temperature measured on Earth since 1931, pending confirma-tion. North of 60°N, the annual mean temperature over Arctic land areas was 2.1°C above the 1981–2010 average, the highest in the 121-year record. On 20 June, a temperature of 38°C was observed at Verkhoyansk, Russia (67.6°N), provisionally the highest temperature ever measured within the Arctic Circle. Near the opposite pole, an atmospheric river—a long, nar-row region in the atmosphere that transports heat and moisture from sub-tropical and midlatitudes—brought extreme warmth from sub-tropical and midlatitudes to parts of Antarctica during austral summer. On 6 February, Esperanza Station recorded a temperature of 18.3°C, the highest temperature recorded on the continent, surpassing the previous record set in 2015 by 1.1°C.
The warmth also led to the largest late-summer surface melt event in the 43-year record, affecting more than 50% of the Antarctic Peninsula. In August, daily sea ice extent in the waters surrounding Antarctica shifted from below to above average, marking the end of persistent below-average sea ice extent since austral spring 2016.In the Arctic, when sea ice reached its annual maximum extent in March, thin, first-year ice comprised ~70% of the ice; the thickest ice, which is usually more than four years old, had declined by more than 86% since 1985 to make up just 2% of total ice in 2020. When the minimum sea ice extent was reached in September, it was the second smallest except for 2012 in the 42-year satellite record.
The Northern Sea Route along the Siberian coast was open for about 2.5 months, from late July through mid-October, compared to less than a month typically.Glaciers across the global cryosphere lost mass for the 33rd consecutive year, and permafrost temperatures continued to reach record highs at many high latitude and mountain locations. In the Northern Hemisphere, lakes froze three days later and thawed 5.5 days earlier on average. In Finland, the average duration of lake ice was 42 days shorter. Record high spring temperatures in central Siberia drove rapid snow melt that contributed to the lowest June snow cover extent across Eurasia in the 54-year record. As is typical, some areas around the world were notably dry in 2020 and some were notably wet. The Middle East experienced an extreme drought during autumn, with most places reporting no precipitation in October. In South America, the Bolivian lowlands suffered one of its most severe droughts on record during autumn. Drought also spanned the Chaco and Pantanal in Bolivia, Paraguay, and southern Brazil. The Paraguay River shrank to its lowest levels in half a century. A decadal “mega drought” in south-central Chile continued through its 11th year, with extreme conditions in the most populated areas. Argentina reported its driest year since 1995. In North America, drought continued to prevail in the West. The lack of moisture in drought-stricken regions often pro-vide ideal conditions for fire. Total fire emissions in the western United States in 2020 were almost three times higher than the 2003–10 mean. The Arctic experienced its highest fire year in terms of carbon emitted into the atmosphere, surpassing the record set in 2019 by 34%, with most of the fires occurring in Arctic Asia.
In the tropics, the Amazon saw its highest fire activity since 2012, while fire activity in tropical Asia—including Indonesia—was one of the lowest on record, related to wet conditions as La Niña evolved during the fire season. The 2020 Southwest Asian Monsoon season (June–September) was the wettest since 1981, also coincident with the emergence of La Niña. The Meiyu rainy season, which usually occurs between July and August over the Yangtze and Huaihe River Valleys of China, was extended by two months in 2020. The May–October total rainfall averaged over the area was the most since the start of the record in 1961. Associated severe flooding affected about 45.5 million people. A widespread desert locust infestation during 2019–20 impacted equatorial and northern East Africa, as heavy rains and prevailing winds were favorable for breeding and movement of swarms across Kenya, Ethiopia, northeastern Somalia, Uganda, South Sudan, and northern Tanzania. The massive infestation destroyed thousands of square kilometers of cropland and pasture lands, resulting in one million people in need of food aid in Ethiopia alone. Extremely heavy rains in April also trig-gered widespread flooding and landslides in Ethiopia, Somalia, Rwanda, and Burundi.
The Lake Victoria region was the wettest in its 40-year record. Across the global oceans, the average ocean heat content reached a record high in 2020 and the sea surface temperature was the third highest on record, surpassed only by 2016 and 2019. Approximately 84% of the ocean surface experienced at least one marine heatwave (MHW) in 2020. For the second time in the past decade, a major MHW developed in the northeast Pacific, covering an area roughly six times the size of Alaska in September. Global mean sea level was record high for the ninth consecutive year, reaching 91.3 mm above the 1993 average when satellite measurements began, an increase of 3.5 mm over 2019. Melting of the Greenland Ice Sheet accounted for about 0.8 mm of the sea level rise, with an overall loss of 293 ± 66 gigatons of ice.A total of 102 named tropical storms were observed during the Northern and Southern Hemisphere storm seasons, well above the 1981–2010 average of 85. In the North Atlantic, a record 30 tropical cyclones formed, surpassing the previous record of 28 in 2005. Major Hurricanes Eta and Iota made landfall along the eastern coast of Nicaragua in nearly the same location within a two-week period, impacting over seven million people across Central America. In the western North Pacific, Super Typhoon Goni was the strongest tropical cyclone to make landfall in the historical record and led to the evacuation of almost 1 million people in the Philippines. Very Severe Cyclonic Storm Gati was the strongest recorded cyclone to make landfall over Somalia. Bosaso, in northeast Somalia, received 128 mm of rainfall in a 24-hour period, exceeding the city’s average annual total of 100 mm.Above Earth’s surface, the annual lower troposphere temperature equaled 2016 as the highest on record, while stratospheric temperatures continued to decline. In 2020, the stratospheric winter polar vortices in both hemispheres were unusually strong and stable.
Between December 2019 and March 2020, the Arctic polar vortex was the strongest since the beginning of the satellite era, contributing to record low stratospheric ozone levels in the region that lasted into spring. The anomalously strong and persistent Antarctic polar vortex was linked to the longest-lived, and 12th-largest, ozone hole over the region, which lasted to the end of December.more
Abstract
Editor’s note: For easy download the posted pdf of the State of the Climate for 2019 is a low-resolution file. A high-resolution …Abstract
Editor’s note: For easy download the posted pdf of the State of the Climate for 2019 is a low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.more
Abstract
Editors note: For easy download the posted pdf of the State of the Climate in 2021 is a low-resolution file. A hig…Abstract
Editors note: For easy download the posted pdf of the State of the Climate in 2021 is a low-resolution file. A high-resolution copy of the report is available by clicking
here
. Please be patient as it may take a few minutes for the high-resolution file to download.more
Abstract
Editors note: For easy download the posted pdf of the State of the Climate in 2022 is a low-resolution file. A hig…Abstract
Editors note: For easy download the posted pdf of the State of the Climate in 2022 is a low-resolution file. A high-resolution copy of the report is available by clicking
here
. Please be patient as it may take a few minutes for the high-resolution file to download.more