WMO Statement on the Status of the Global Climate in 2009

WMO statement on the status of the global climate in 2009

WMO-No. 1055 WMO-No. 1055

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WMO in collaboration with Members issues since 1993 annual statements on the status of the global climate. This publication was issued in collaboration with the Hadley Centre of the UK Meteorological Office and the Climatic Research Unit, University of East Anglia, United Kingdom of Great Britain and Northern Ireland; and the National Climatic Data Center, the National Environmental Satellite, Data, and Information Service, and the National Weather Service of the National Oceanic and Atmospheric Administration (NOAA), the Goddard Institute for Space Studies operated by the National Aeronautics and Space Administration (NASA), and the National Snow and Ice Data Center, United States of America. Other contributors are the National Meteorological and Hydrological Services of Algeria, Argentina, Australia, Brazil, Canada, China, Colombia, Ecuador, Finland, France, Germany, Iceland, India, Japan, Morocco, Spain, Sweden, Tunisia, Turkey and Uruguay. The WMO Regional Association VI (Europe) Regional Climate Centre on Climate Monitoring, the African Centre of Meteorological Applications for Development (ACMAD, Niamey), the Australian Commonwealth Scientific and Industrial Research Organization (CSIRO), the International Research Centre on El Niño (CIIFEN, Guayaquil, Ecuador), the Intergovernmental Authority on Development (IGAD) Climate Prediction and Applications Centre (ICPAC, Nairobi), the Southern African Development Community Drought Monitoring Centre (SADC DMC, Gabarone) and the World Climate Research Programme (WCRP) also contributed.

Cover: The beauty and variety of the weather. Illustration by Felix Jegenberg, 8 years old, Sweden

NOTE

The designations employed in WMO publications and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of WMO concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries.

Opinions expressed in WMO publications are those of the authors and do not necessarily reflect those of WMO. The mention of specific companies or products does not imply that they are endorsed or recommended by WMO in preference to others of a similar nature which are not mentioned or advertised. Foreword

Since 1993, the World Meteorological and precipitation variations, tropical cyclones, Organization (WMO) has been issuing its drought and flooding, snow cover and sea annual “WMO Statement on the Status of ice, the ozone layer and many other critical the Global Climate”, which has become an weather, climate and water parameters moni- authoritative regular source of information, tored across the world over the year which eagerly sought by the scientific community has concluded. and the media. Equally outstanding were the continuing The present Statement is the latest addition to efforts of several climate centres to develop this successful series, and a key result is that the long-term homogeneous datasets required the period 2000–2009 was the warmest dec- to support the authoritative assessments that ade on record since the beginning of modern contributed to the work of WMO, the United instrumental measurements around 1850. Nations Framework Convention on Climate Change, the Intergovernmental Panel on A number of extreme weather and climate Climate Change, the World Climate Research events were recorded in 2009, including in Programme and other key scientific activities particular heatwaves in China, India and south- across the world. ern Europe, as well as in Australia. Severe droughts, intense storms and flooding were I therefore wish to express the gratitude of also registered in different parts of the world, the World Meteorological Organization to all and the end of 2009 was notably cold in the contributors to the WMO Statement on the northern hemisphere, with heavy snowfall in Status of the Global Climate in 2009. Europe, North America and northern Asia.

Furthermore, the year concluded with a moderate El Niño event, which is being continuously monitored.

It is essential to underscore the vital role of the National Meteorological Services of the 189 Members of WMO and of many WMO partners for their key efforts to maintain the necessary observing infrastructure and the information systems, which permitted the (M. Jarraud) exchange of data and analyses of temperature Secretary-General

Global temperature during 2009 Note: There are three independent datasets used for the analysis of the global temperature anomaly. Based on two The year 2009 is nominally ranked as the fifth global datasets maintained independently by the Met Office warmest year on record since the beginning Hadley Centre and Climatic Research Unit, University of of instrumental climate records around 1850. East Anglia in the United Kingdom and the National Climatic On the decadal scale, the analysis shows that Data Center of the National Oceanic and Atmospheric the 2000s decade (2000–2009) was warmer Administration (NCDC–NOAA) in the United States, the than the 1990s (1990–1999), which in turn analysis of the global surface temperature for the year Figure 1. Global ranked were warmer than the 1980s (1980–1989) and 2009 shows anomalies of +0.44°C (+0.59°F) and +0.46°C surface temperatures earlier decades. (+0.63°F) in the two datasets, respectively, with reference for the warmest to the 1961–1990 long-term average of 14°C (57.2°F). A third 50 years. Inset shows Global temperature assessment is provided dataset, which is maintained by the Goddard Institute for global ranked surface with an uncertainty margin that affects the Space Studies operated by the National Aeronautics and temperatures from 1850. global surface temperature The size of the bars figures and consequently their indicates the 95 per cent ranking, mainly as a result of the confident limits associated with each existing gaps in data coverage. year. The source data The magnitude of the uncertainty are blended land surface in assessing the global surface temperature in 2009 is estimated air temperature and sea Rank surface temperature at 0.10°C. Therefore, the most from HadCRUT3 series likely value of the global surface (Brohan and others, temperature anomaly for 2009 is 2006). Values are simple between +0.34°C and +0.56°C. from 1961–1990 average area-weighted averages emperature difference (°C) T for the whole year. The southern hemisphere was (Source: Met Office Hadley particularly warmer than the Centre, UK, and Climatic long-term average, especially Research Unit, University of during the austral winter and East Anglia, UK) late spring. Rank of hottest years to coldest

Figure 2. Annual global average temperature 0.6 anomalies (relative to 1961–1990) from 1850 HadCRUT3 0.4 to 2009 from HadCRUT3 NCDC (black line and grey area, representing mean and GISS 95 per cent uncertainty 0.2 range), the NOAA National Climatic Data Center (red) and the 0.0 NASA Goddard Institute for Space Studies (blue) (Source: Met Office Hadley – 0.2 Centre, UK, and Climatic Research Unit, University of East Anglia, UK) – 0.4

– 0.6 Anomaly (°C) relative to 1961–1990

– 0.8 1850 1900 1950 2000 Space Administration (NASA) in the United States, shows 2000–2009 14.42 Figure 3. Decadal global a global surface temperature anomaly of +0.50°C for 2009, 1990–1999 14.25 average combined 14.09 1980–1989 land–ocean surface which is in the same range as above. Information on source 1970–1979 13.93 and methodology for global surface temperature assessment 1960–1969 13.90 temperature (°C) 13.85 1950–1959 combining two global is provided on page 12. 1940–1949 13.94 1930–1939 13.87 temperature datasets 1920–1929 13.72

Decade (Sources: (a) Met Office 1910–1919 13.60 1900–1909 13.61 Hadley Centre, UK, and Regional temperature anomalies 13.68 1890–1899 Climatic Research Unit, 1880–1889 13.74 Average 1961–1990 1870–1879 13.77 University of East Anglia, According to the reports provided by the 13.63 1860–1869 UK; (b) National Climatic National Meteorological and Hydrological 1850–1859 13.61 Data Center, NOAA, United Services, above-normal annual temperatures 13.4 13.6 13.8 14.0 14.2 14.4 14.6 States. The only dataset were recorded in 2009 in most parts of the Global Temperature (°C) continents. However, parts of the United States with monthly mean temperature anomalies available for decades and Canada, and central Siberia experienced of more than +5°C in some places. The mean 1850–1859, 1860–1869 and cooler temperatures than average. During the April temperatures ranged between 10°C and 1970–1979 is (a)). year, extreme warm episodes were frequently 15°C compared to the long-term average values recorded in southern South America, Australia ranging between 5°C and 10°C. The summer and southern Asia. In the southern hemisphere, was also warmer than the long-term average, August and November set new temperature particularly over southern Europe. Spain had records. the third warmest summer after the very hot summers of 2003 and 2005. However, a very Europe cold October was reported in Scandinavia, with In Europe, warmer-than-average temperatures mean temperature anomalies ranging from were recorded during most of the year. In –2°C to –4°C. Early winter 2009/2010 started some parts of western and central Europe, with an extended cold wave of more than a colder-than-average conditions were recorded week in most of Europe. On some days in at the beginning of the year. Spring was very December, the minimum temperature dropped warm in Europe. April was particularly mild to –40°C in some locations in Scandinavia, in Germany, the Czech Republic and Austria –17°C in northern Italy and below –20 °C in the

90N Figure 4. Global field of land surface and sea surface temperature 60N anomalies (°C), relative to 1961–1990 for 2009 (Source: Met Office Hadley 30N Centre, UK, and Climatic Research Unit, University of 0 East Anglia, UK)

30S

60S

90S 180 120W 60W 0 60E 120E 180

–10 –5 –3 –1 –0.5 –0.2 0 0.2 0.5 1 3 5 10

Arctic Sea Ice Third lowest extent on record in September, Alaska North America snow cover extent behind 2007 and 2008. September 1996 Had its second Third largest October snow cover extent on record; was the last year with above average sea Russian Federation warmest July, largest December snow cover extent on record ice extent. Ireland Experienced anomalously cool conditions during February 2009. Temperature anomalies across most of the Russian behind 2004, Canada Experienced its coolest Central Europe Federation ranged from 3–6°C below the 1961–1990 average. on record A tornado claimed the lives of three people in December in 28 years Heavy rain triggered floods, Ontario, the first tornado-related fatalities in Canada United Kingdom causing central Europe’s worst China since 1995 (July). Toronto, Ontario had a snow-free Mean temperature of 3.2°C during winter natural disaster since Heavy snow over parts of northern China; Western North Pacific typhoon season November for the first time in recorded history. 2008/2009, the coldest since 1996/1997; the 2002 floods (June). heaviest snowfall in 55 years for the Below average activity heavy snow in parts of the country (February), the Hebei province and in history for the 22 storms, 13 typhoons worst snowstorm since February 1991; wettest Turkey Shaanxi province (November) November since records began in 1914, exceeding United States North-western Turkey received its China the previous record set in 1951; coolest Record floods on the Red River in heaviest rainfall in 80 years in Suffered from its worst drought Japan Hurricane Rick (October) December since 1995. In Scotland, twice the the northern Plains region (March); wettest a 48-hour period (September). in five decades. Drought conditions affected over Torrential rain across south-western Japan led to flooding and Maximum winds 285 km/h October since records began 115 years average August rainfall; tied with 1985 as the Italy 4 million people (February). Violent storms across central landslides (July). The area had a record amount of rainfall in July. The second most intense Eastern ago; below average tornado season wettest August since national records began Experienced its worst mudslide in China destroyed nearly 9 800 homes and caused up North Pacific hurricane on record, Typhoon Morakot (August) after record activity in 2008 in 1914 more than a decade, when 229 mm to US$ 39 million in agricultural losses (June). behind Linda of 1997, and the Spain and France India Maximum winds 155 km/h Atlantic hurricane season of rain fell in a 3-hour period Bhutan The deadliest typhoon to hit Taiwan Province of China since records strongest hurricane to form in Mexico Extratropical Storm Klaus India experienced its Below average activity in Sicily (October) Received its heaviest began; prompted the worst flooding in five decades on the island; October since reliable records began Experienced (equivalent to a category 3 hurricane), weakest monsoon 9 storms, 3 hurricanes Saudi Arabia rainfall in 13 years destroyed over 10 000 homes and caused 614 fatalities severe to responsible for 30 fatalities (January), season since 1972, Hurricane Andres (June) Jeddah had its worst (October) exceptional Hurricane Ida (November) was the worst storm to hit the region with 23 per cent below Typhoon Ketsana (September) Maximum winds 130 km/h floods in nearly three Andres was Eastern North Pacific’s latest drought conditions Maximum winds 165 km/h since a December 1999 storm that normal rainfall on Bangladesh Maximum winds 165 km/h decades (November). Dhaka received 290 mm arrival of a named storm since reliable (September) Brought heavy rain across Nicaragua and claimed 88 lives. average across the World’s second deadliest tropical cyclone of 2009; caused Manila’s worst of rain on 29 July, records began in 1970. Honduras; made landfall in the United States nation for the season. flooding in 40 years. The heaviest precipitation (424 mm) fell in a 12-hour as a tropical storm, producing heavy rain East Africa the largest rainfall period, breaking a 24-hour record (335 mm) set in 1967 and surpassing Eastern North Pacific Guatemala across the south-eastern region Burkina Faso Drought led to massive food in a single July the average September monthly rainfall (391 mm) for the area. Heavy rain and floods affected shortages. In Kenya, the India hurricane season Drought decreased day since 1949. Colombia 150 000 people; 263 mm of drought was responsible Heavy rain fell over the Philippines Near average activity harvests by up to 50 per Copious rainfall triggered widespread rain fell in a 12-hour period, for the loss of over southern states, leaving Received well above average precipitation during October; mainly due 20 storms, 8 hurricanes cent; 400 000 families floods across western Colombia. Nearly breaking a record last set 150 000 livestock and a 2.5 million people homeless to the combined effects of typhoons Parma, Lupit and Mirinae, which were affected (September). 2 500 families were affected (February). 90 years ago (September). 40 per cent decrease in and claiming the lives of nearly brought torrential rain across the islands, triggering fatal floods (October) 300 people (October). ENSO maize harvests. Overall, Zambia and Namibia 23 million people were La Niña conditions transitioned into a warm Brazil Papua New Guinea Torrential rain prompted the affected (September). North Indian Ocean phase ENSO (El Niño) in June. Torrential downpours caused Indonesia Heavy downpours triggered a fatal floods and mudslides, affecting overflow of rivers, flooding homes cyclone season Near average activity Heavy rain over Jakarta caused landslide (March). over 186 000 residents. This and cropland. Nearly 1 million people a 76-year-old dam to burst. 5 storms, 1 cyclone Peru region experienced its worst were affected. The Zambezi River The wall of water inundated Tropical Cyclone Hamish reached its highest level since Torrential rainfall deluge in over 20 years (April). hundreds of homes (March). Maximum winds 215 km/h 1969 (March and April). fell over Peru’s South Indian Ocean The most intense cyclone observed off the south-eastern region Australia cyclone season Record-breaking heatwave affected eastern Queensland coast since 1918 of Puno, resulting in a Near average activity deadly landslide (March). South-eastern South America southern Australia during January/February. 16 storms, 7 cyclones Accompanying very dry conditions contributed to Between September and December, South Pacific tropical Argentina the development of deadly wildfires. Also, Australia several intense storms severely affected Tropical Cyclone Fanele (January) cyclone season Heavy rainfall caused a had its warmest August and warmest November this region, producing daily and monthly Maximum winds 185 km/h Below average activity devastating landslide in northern since national records began 60 years ago. Argentina, destroying over records of rainfall as well as flooding. Brought heavy rain and strong winds to 10 storms, 1 cyclone 300 homes and affecting nearly Madagascar; affected nearly 28 000 people 20 000 people (February). Global tropical cyclone activity Southern hemisphere Below average activity Characterized by recording one of the warmest 81 storms years with August and November 2009 at the New Zealand 33 hurricanes/typhoons/cyclones top of their ranking Warmest August since national records 19 “major” hurricanes/typhoons/cyclones began 155 years ago; experienced cool Argentina conditions during October 2009, resulting An extremely cold November affected Antarctic ozone hole: 24 million km² at its peak in the coolest October since 1945 the Patagonia region. Late snowfalls broke in mid-September; fifteenth largest on record since frequency records in some locations, where satellite records began in 1979 4–11 days with snow were reported.

north-east of France. The combination of cold higher-than-average temperatures. India weather and extensive snowfalls was unusual recorded its warmest year since 1901 with a in the United Kingdom, which experienced the mean temperature anomaly of +0.93°C. China most prolonged spell of freezing temperatures had its fourth warmest year since 1951. The and snowfall across the country since winter year started with a very mild January in large 1981/1982. parts of the continent, although February was particularly cold in the Russian Federation. Asia Spring was warmer than average across the Apart from some areas in northern Asia, whole continent, as was summer in most parts the rest of the continent experienced of the region. Temperatures during December

were well below average over northern Asia and February. Spring presented a similar Figure 5. Significant with monthly temperature anomalies ranging pattern to that observed in the winter, with a climate anomalies and between –4°C and –8°C. predominance of below-normal temperatures events in 2009 in Canada and above-normal temperatures (Source: National Climatic North America in the rest of the region. In late July, many Data Center, NOAA, United The year started with colder-than-normal cities in Canada recorded their warmest daily States) weather conditions over the Great Lakes region temperatures; for example, Victoria set a in Canada, as well as the north-east of the new record of 35°C on 29 July. Conversely, United States and Alaska. The rest of the United October was colder than the long-term aver- States and Mexico experienced a mild January age across the United States. For the nation

as a whole, it was the third coolest October on Australia record, with an average temperature anomaly In Australia, 2009 was the second warmest of –2.2°C (–4°F). Oklahoma recorded the low- year in a temperature series that began in 1910. est monthly mean temperature for October The average temperature was 0.9°C above (12.3°C); the previous record (12.4°C) was the 1961–1990 long-term average. Summer set in 1925. December was also colder than was very warm, except in the north, which normal across most of the United States with experienced colder-than-normal conditions in monthly temperature anomalies around –5°C conjunction with an active monsoon. Winter in the central and western regions. was exceptionally mild over much of Australia. In August, maximum temperatures were well South America above normal across the entire continent, During 2009, warmer-than-normal condi- recording up to 7°C above the monthly long- tions predominated across the region, with term average in some places; the national the south most affected. Argentina had its mean maximum temperature anomaly of warmest year of the last five decades. The +3.2°C was the highest ever recorded for austral summer was warmer than normal in any month. November was also very warm Chile, Argentina and eastern Brazil, while the across the south-eastern region with mean north-east of the region experienced cooler- maximum temperature anomalies between than-normal conditions. Autumn (March to +4°C and +8ºC. May) was particularly warm in Argentina, Uruguay, Paraguay and southern Brazil. In fact, a large part of central Argentina recorded Heatwaves and cold waves the warmest autumn since 1961 with seasonal temperature anomalies ranging between +2°C Italy recorded two heatwaves in the second and +3°C. August was exceptionally warm half of July with maximum daily tempera- in southern South America and many new tures above 40°C; some local temperatures daily maximum temperature records were soared to 45°C. An extreme heatwave also hit set; for example, Buenos Aires set a new India during May, which caused 150 deaths. record of 34.4°C on 30 August. However, in Northern China also experienced a heatwave June and July below-normal temperatures during June when daily maximum tempera- were recorded in Paraguay, Uruguay and tures rose above 40°C; historical maximum southern Brazil. Abnormally cold condi- temperature records were broken for the sum- tions also prevailed in the southern part of mer in some locations. Australia was marked Argentina, with several late snowfalls and by exceptional heatwaves, which affected frosts in November. the south-eastern part of the country in

Figure 6. Monthly air surface temperature anomalies over Europe showing departures in degrees Celsius, 1961–1990 base for December 2009 (Source: Deutscher Wetterdienst, Germany) Less than –4 –4 to –3 –3 to –2 –2 to –1 –1 to 0 0 to 1 1 to 2 2 to 3 3 to 4 Greater than 4

–15 and beginning of November. Unusually high Figure 7. Mean maximum temperatures of above 40°C were recorded in temperature anomalies (°C) over southern South –20 many places and for several consecutive days. Several daily temperature records were bro- America during austral ken, often by a wide margin; in some locations autumn 2009 –25 (Source: National 5 the annual absolute maximum temperature records were also broken, such as the 47°C Meteorological Service of 4 –30 temperature recorded in Catamarca. Argentina) 3 2 Northern China was affected by very low –35 1 temperatures during the first half of November as part of an early cold wave. Large parts 0 –40 of the United States, central and northern –1 Europe and northern Asia were affected by –45 –2 an extended cold wave during the second –3 half of December, the intensity varying with geographical location. For example, Germany –50 –4 reported daily minimum temperatures ranging –5 between –10°C and –25°C with several loca- –55 tions setting new daily minimum records in –75 –70 –65 –60 –55 –50 –45 –40 at least six decades. In Switzerland, Geneva recorded –12.6°C, the lowest temperature for December since the temperature dropped to January/February and November, and the –14°C in 1968. Some minimum daily tempera- subtropical eastern part in August. The ture records were also tied or broken in the January/February heatwave was associated United States. with disastrous bushfires that caused more than 173 fatalities. Victoria recorded its highest temperature with 48.8°C at Hopetoun, the Global precipitation highest temperature ever recorded so far south anywhere in the world. Global precipitation during 2009 was near the 1961–1990 average. However, regionally, Argentina was affected by an exceptional drier-than-average conditions were recorded heatwave affecting the northern and central across Alaska’s panhandle, southern Australia, part of the country at the end of October southern South America, and parts of Western

90N Figure 8. Annual precipitation anomalies for global land areas for 60N 2009; gridded 1.0-degree raingauge-base analysis 30N as normalized departures in mm/month from normal focusing on 0 1951–2000 base period (Source: Global Precipitation 30S Climatology Centre, Deutscher Wetterdienst,

60S Germany)

90S 180 120W 60W 0 60E 120E 180

–70 –50 –30 –10 10 30 50 70

Figure 9. Percentage of precipitation anomaly (%) over China during summer 2009 (Source: China Meteorological Administration)

> 80 60 to 80 30 to 60 10 to 30 0 to 10 –10 to 0 –30 to –10 –60 to –30 –80 to –60 < –80

Europe and southern Asia. On the other hand, Nevertheless, the total area affected by drought south-eastern Brazil, Uruguay, parts of eastern in the United States during October was the and south-eastern Asia, most of Europe and second smallest value recorded during the the eastern half of the contiguous United decade. States experienced wetter conditions than the long-term average. Drought in central Argentina caused severe damage to agriculture, livestock and water resources. The situation was most severe at Severe droughts the end of October, in combination with the recorded high temperatures. China suffered from severe drought during most of the seasons in 2009. Water levels in parts of the Gan and Xiangjiang Rivers were Intense storm events and flooding the lowest in 50 years. In India, the poor monsoon season was reported to be one of the At the end of January, Spain and France were weakest since 1972. It caused severe drought severely affected by winter storm Klaus, impacts in 40 per cent of the districts and the the worst extra-tropical storm in a decade, north-western and north-eastern parts of the with wind speeds equivalent to a Category 3 country were severely affected. hurricane. During the same month, a win- try storm combined with heavy snowfall In East Africa the drought led to massive food caused severe damage in Western Europe shortages. In Kenya the drought was respon- and resulted in serious disruptions to air and sible for severe damage to livestock and a rail traffic in several countries. In late spring 40 per cent decline in the maize harvest. and summer, a large number of thunder- storms with heavy rain, hail and tornadoes In North America, Mexico experienced caused local flooding and significant damage severe-to-exceptional drought conditions by across Germany. In September, several parts September. In the United States, the western of the Mediterranean region were affected region was the most affected by a moderate- by extreme rainfall events. Total rainfall of to-exceptional drought by the end of October. more than 300 mm was recorded in less than

48 hours in one location in south-eastern 15 years – hit the southern part of Argentina. Spain, where the long-term average of total During the austral spring, particularly in annual precipitation does not exceed 450 mm. November, continuous, heavy and intense During the same month, intense rainfall rainfall in north-eastern Argentina, southern caused devastating damage to infrastructure Brazil and Uruguay caused flooding in many in several parts of northern Africa, including places, affecting more than 15 000 people. Algeria, Morocco and Tunisia. In Turkey the Total monthly precipitation records were extreme weather events recorded during broken, with rainfall exceeding 500 mm in 2009, including severe storms, tornadoes, many locations. frosts, hail storms, floods and landslides, marked a record high since 1941. November In Canada, Ontario experienced a record brought severe flooding to areas of the north- number of witnessed tornadoes and a record ern United Kingdom, with daily rainfall of number of related fatalities. Canadian ava- more than 200 mm in Seathwaite, totalling 379 lanches were almost double the yearly average mm in 48 hours. It was the wettest November for the past decade and the worst since for the United Kingdom as a whole since 1914. 2002/2003. A total of 25 deaths made it one The year ended with significant snowstorms of the deadliest seasons. The northern plains and extreme frosts all over Europe, which region of the United States was affected by resulted in some damage and transport dis- record flooding during March. As a whole, the ruptions. A record-breaking 13-month-long United States recorded the wettest October in storm-free period in Swedish coastal waters 115 years. A major snowstorm hit the north- ended on 25 December when local storm east region of the country in the second half of winds swept the Swedish east coast. December, setting new snowfall records from Washington to Boston. Travel of every type During the beginning of the year heavy rain- was disrupted; airports, interstate highways fall was observed in Colombia, producing and local roads were closed, and rail lines landslides and widespread floods. North- were shut down. east Brazil was severely affected by heavy rainfall and flooding in April and May. In In Central America, an intense storm in El July, a severe snowstorm – the worst in Salvador in November, associated in part

Figure 10. Australian rainfall deciles for the year 2009. Deciles are Rainfall decile ranges calculated relative to the period 1900–2009, Highest on with distribution based record on gridded data from the Very much 10 above average National Climate Centre. (Source: Commonwealth of 8–9 Above average Australia, Australian Bureau 4–7 Average of Meteorology)

2–3 Below average Very much 1 below average Lowest on record

with Hurricane Ida, produced deadly floods Tropical cyclone season and landslides that claimed 192 lives. The 2009 Atlantic hurricane season closed In Asia, after the weak 2009 monsoon season, with the fewest named storms and hurricanes southern India recorded severe flooding due to since 1997, most likely owing to the unfavour- incessant rain in late September and the first able cyclonic conditions caused in part by El week of October, and around 300 lives were Niño. A total of nine named tropical storms lost. Northern China was severely affected by were formed, including three hurricanes, two a snowstorm that occurred during the first half of which were major hurricanes at Category 3 of November as part of a strong cold air mass strength or higher, compared with averages outbreak. The snow fell one month earlier than of 11, 6 and 2, respectively. normal, breaking local weather records. In the Eastern North Pacific, 20 named tropi- In western Africa, heavy and intense rainfall cal storms were recorded, 8 of which evolved in September caused flooding that affected into hurricanes and 5 of which became major more than 100 000 people. The worst flooding hurricanes, compared with averages of 16, 9 was observed in Burkina Faso, where 263 mm and 4, respectively. of rain was recorded in less than 12 hours, breaking a record set 90 years ago. Further In the western North Pacific, 22 named tropical south on the continent, nearly 1 million people storms were recorded, 13 of which reached the in Zambia and Namibia were affected by tor- intensity of typhoon, compared with the long- rential rain that caused rivers to overflow their term averages of 27 and 14, respectively. Heavy banks, flooding homes and cropland. precipitation associated with typhoons Ketsana and Parma was observed across the south of Australia was also affected by local flooding. Luzon Island in the Philippines. The resulting Heavy monsoon rains caused widespread flood disaster caused more than 900 fatali- flooding in north-eastern Australia in January ties. In August, Typhoon Morakot swept across and early February. Subsequently, coastal Taiwan Province of China and caused more than Queensland and New South Wales were the 600 deaths and severe damage to agriculture and hardest hit by several heavy rains, with daily infrastructure. Hundreds of roads and bridges rainfall totals in excess of 300 mm. Conversely, on the island were destroyed by floods. numerous duststorms affected eastern Australia in the second half of September The Australian and South Pacific Ocean cyclone and early October. The most severe dust- seasons recorded near-average activity. In storm occurred on 22–23 September and the Australian region, there were 10 systems covered large parts of New South Wales and during the season. Although it did not make Queensland, where the visibility was reduced landfall, Hamish was the most significant, to 100–200 m in both Sydney and Brisbane. reaching Category 5 intensity. It was the most intense cyclone observed off the eastern Queensland coast since 1918. End of La Niña and development of El Niño The South Indian Ocean cyclone season La Niña-like conditions were present in early recorded near-average activity with 16 storms, 2009, followed by the development of El Niño 7 of which were cyclones. Tropical Cylcone patterns starting in June 2009. During June– Fanele made landfall in Madagascar in January September 2009, sea surface temperatures were and brought heavy rain and strong winds and generally about 1°C warmer than the long-term affected nearly 28 000 people. average across the central and eastern equatorial Pacific. There was a rapid intensification of the event to moderate levels during October, with Arctic sea ice the peak of the mature phase being reached in late December. Most equatorial regions east of The National Snow and Ice Data Center near- the Date Line were more than 1°C warmer than real-time Defense Meteorological Satellite average by that time, with a few regions more Program (DMSP) Special Sensor Microwave than 2°C above average. Imager (SSM/I) Daily Polar Gridded Sea Ice

10 2009 2008 2007 Figure 11. Sea-ice extent for September 2009 (third lowest on record), September 2008 (second lowest on record) and September 2007 (lowest on record). The magenta/ orange line indicates the long-term median from the 1979–2000 base period. (Source: National Snow and Ice Data Center, United States)

Concentrations and the Sea Ice Concentrations of the reference period 1979–2000, the Arctic from the Nimbus-7 Scanning Multichannel sea ice at the end of the melt season in 2009 Microwave Radiometer (SSMR) and DMSP was 76 per cent of the long-term average of SSM/I Passive Microwave Data datasets are 6.71 million km2 compared with 67 per cent used to generate the monthly records of sea- in 2008 and 62 per cent in 2007. According to ice extent and sea-ice concentration for the scientific measurements, Arctic sea ice has Arctic and Antarctica from satellite passive declined dramatically over the past 30 years, microwave data. with the most extreme decline seen in the summer melt season. Arctic sea-ice extent during the 2009 melt season was a minimum extent of 5.10 million km2, ranking third lowest on record after Antarctic ozone hole 2007 (4.13 million km2) and 2008 (4.52 million Figure 12. The plot shows the daily evolution of km2) since satellite measurements began in The daily maximum ozone hole for 2009 was the surface area of the 1979. Compared with the long-term average 24.1 million km2 on 17 September. This is Antarctic ozone hole over the course of the ozone hole season. The 6 2 Ozone Hole: Area [10 km ] blue horizontal lines 30 2009 show the surface area of 2008 the various regions for comparison. 25 2007 North America (Source: The graph was prepared by the World Data 20 Centre for Remote Sensing of the Atmosphere, one of the Global Atmosphere 15 Antarctica Watch World Data Centres, hosted by the German Europe 10 Aerospace Center in Australia Germany. The data used to produce this graph 5 were derived from the METOP-A/GOME-2 and ENVISAT/SCIAMACHY 0 sensors and are the result of August September October November December several algorithms.)

11 5.5 million km2 more than the 1979–2000 minimum daily minimum ozone during 2009 long-term average and about 6 million km2 was reached on 26 September with 94.0 DU. less than the record of almost 30 million km2 This is below the 1979–2000 long-term average in 2000. Compared with the average size over of 125.4 DU. This ranks 2009 (together with the 7 September–13 October time period, the 1991) as the seventh lowest daily minimum ozone hole in 2009 was the fifteenth largest ozone on record in the southern hemisphere. on record since satellite records began in The record low was observed in 1994 with 1979. Measured in Dobson Units (DU), the 73.0 DU.

Source and methodology for global surface temperature assessment

Global average temperature records are The development of climate datasets is based essential to help understand how the climate on the following: is changing. To understand changes and variations in the climate it is essential to know • Routinely disseminated daily and monthly how the surface temperature changes – from weather and climate observations by the month to month, up to decade to decade. Global National Meteorological and Hydrological average temperature records provide this vital Services of the 189 WMO Members follow- information. From these records it can be seen ing the WMO standards for data collection, how warm specific months, years or decades quality control and exchange; are, and trends can be discerned in the climate system over longer periods of time. • Historical climate records dating back to 1850, including those available from marine The global surface temperature assessment climate summaries; is based on the instrumental records of the air temperature measured at 1.25 to 2 metres • Recovered old climate records worldwide above the surface level on the land. Sea sur- as part of continuous data rescue efforts face temperature measurements are recorded promoted by WMO and its Members; by various observation platforms, including ships and buoys. The annual assessment is • Peer reviewed scientific methods for quality based on these measurements after they have control, homogenization and interpolation been quality controlled to filter data errors to constitute high-quality global climate and homogenized. datasets.

There are three centres that maintain global Temperature anomalies climate datasets and calculate global average temperature and related anomalies at monthly Absolute temperatures are not used directly and annual timescales: to calculate the global average temperature. They are first converted into anomalies, • Met Office, UK, in collaboration with the which are the difference in temperature Climatic Research Unit at the University of from the normal level. The normal level is East Anglia (United Kingdom); calculated for each observation location by taking the long-term average for that • National Climatic Data Center, which is part area over a base period. One of the main of NOAA (United States); reasons for using anomalies is that they remain fairly constant over large areas. The • Goddard Institute for Space Studies, which anomaly method also helps to avoid biases. is part of NASA (United States). For example, if actual temperatures were

12 used and information from an Arctic obser- and processed to ensure consistency. This vation station were missing for that month, includes recording information about the the global temperature record therefore local environment around the observation would seem warmer. Thus, when anomalies station and any changes to that environment. are used such missing data will not bias the This is important for ensuring the required temperature record. data accuracy and performing homogeneity tests and adjustments. There are additional uncertainties because temperatures over large Accuracy of the observations areas of the Earth are not observed as a mat- ter of routine. These elements are taken into Each observation station follows international account by factoring the uncertainty into global standards for taking observations set out by average temperature calculations, thereby WMO. Each National Meteorological Service producing a temperature range rather than provides reports on how its data are collected one uniquely definite figure.

13 For more information, please contact: World Meteorological Organization

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