WMO Statement on the Status of the Global Climate in 2008

WMO statement on the status of the global climate in 2008

WMO-No. 1039 WMO-No. 1039

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ISBN 978-92-63-11039-8

Cover: Landscape. Illustration by Andrea Agius, 14 years old, Malta

This publication is issued in collaboration with the Hadley Centre of the UK Meteorological Office; the Climatic Research Unit, University of East Anglia, United Kingdom of Great Britain and Northern Ireland; the National Climatic Data Center, National Environmental Satellite, Data and Information Service, and National Weather Service of the National Oceanic and Atmospheric Administration (NOAA); 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, Finland, France, Germany, India, Japan, Morocco, Spain, Sweden, Turkey and Uruguay. 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 Global Precipitation Climatology Centre (GPCC, Offenbach, Germany), the IGAD Climate Prediction and Applications Centre (ICPAC, Nairobi), the Southern African Development Community Drought Monitoring Centre (SADC DMC, Gaborone) and the World Climate Research Programme also contributed.

NOTE

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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

In 1873 the First International Meteorological report “WMO Statement on the Status of the Congress assembled in Vienna to establish Global Climate”, which by now has become the International Meteorological Organization a well-established source of authoritative (IMO), which by 1929 had launched its information, eagerly sought after every year Commission for Climatology. During August by the scientific community and the media. 1947, the ten IMO technical commissions and its The WMO Statement on the Status of the six regional commissions held their respective Global Climate in 2008 is the latest in this sessions simultaneously in Toronto, Canada. successful series. These meetings immediately preceded the Washington (Eighth) Conference of Directors The year 2008 was notable, in particular, of Meteorological Services, which in October as it signalled positive global temperature 1947 unanimously approved the Convention of anomalies, which positioned it among the a new organization: the World Meteorological ten warmest on record since the beginning Organization (WMO). Following the neces- of modern measurements in 1850. Several sary ratifications, WMO took over the IMO extreme weather and climate events were responsibilities on 23 March 1950 and, one recorded in various parts of the world in 2008, year later, WMO became a specialized agency of which perhaps the most dramatic was of the United Nations system. tropical cyclone Nargis, which made landfall in Myanmar in May, causing catastrophic Fifty years after the founding of the IMO destruction and more than 70 000 fatalities. Commission for Climatology, in 1979 WMO Other parts of the world suffered severe flood- organized the First World Climate Conference, in ing, extreme heatwaves and droughts in 2008, collaboration with the International Council for while Arctic sea ice was once more observed to Science, the Intergovernmental Oceanographic decline markedly, reaching during September Commission of the United Nations Educational, its second-lowest historic extent. Scientific and Cultural Organization, the United Nations Environment Programme (UNEP) I would like to highlight that 2008 was the and the Food and Agriculture Organization second year of the International Polar Year of the United Nations. This historic confer- 2007–2008, a WMO co-sponsored scientific ence led to the establishment of the WMO venture that has already made decisive con- World Climate Programme and, in 1980, to the tributions to our scientific understanding of World Climate Research Programme, which climate in the polar regions. WMO first co-sponsored with the International Council for Science and subsequently also I wish to express the appreciation of WMO to with the Intergovernmental Oceanographic all the Centres and the National Meteorological Commission. Furthermore, the conference and Hydrological Services of WMO Members paved the way for the 1988 establishment of the that collaborated with WMO and contributed WMO/UNEP co-sponsored Intergovernmental to the present publication. As with previ- Panel on Climate Change, which received the ous editions, I would like to underscore the prestigious Nobel Peace Prize in 2007 for its importance of receiving your feedback. WMO efforts “to build up and disseminate greater looks forward to your comments on the WMO knowledge about man-made climate change, Statement on the Status of the Global Climate and to lay the foundations for the measures in 2008 and to your welcome suggestions for that are needed to counteract such change”. its further improvement.

The Second World Climate Conference, which WMO organized with partners in 1990, provided decisive momentum to the international efforts that resulted in the development of the United Nations Framework Convention on Climate Change and the Global Climate Observing System. In the wake of these historic (M. Jarraud) events, WMO began to issue in 1993 its annual Secretary-General

Global temperature during 2008 made by leading climate centres. The Met Office Hadley Centre analyses showed that The year 2008 ranked as one of the warmest the global combined sea surface and land years on record according to the analyses surface air temperature for 2008 was 0.31°C (0.56°F) above the 1961–1990 annual average of 14.0°C (57.2°F), ranking 2008 as the tenth Figure 1. Annual global (a) Globe 0.8 warmest year on record. According to the and hemispheric 0.6 National Climatic Data Center of the National combined land surface 0.4 0.2 Oceanic and Atmospheric Administration, the air temperature and sea 0.0 global mean surface temperature anomaly was surface temperature −0.2 −0.4 0.49ºC (0.88ºF) above the twentieth century (SST) anomalies (°C) for −0.6 −0.8 average (1901–2000), which ranks 2008 as the the period 1850–2008, −1.0

Difference (°C) from 1961−1990 eighth warmest year on record. relative to the average 1860 1880 1900 1920 1940 1960 1980 2000 for 1961–1990. The (b) Northern hemisphere 0.8 Based on the joint Met Office Hadley Centre source data are 0.6 0.4 and Climate Research Unit, University of blended land surface air 0.2 East Anglia analyses, in 2008 the northern temperature and SST 0.0 −0.2 and southern hemispheres, with a mean from the HadCRUT3 −0.4 −0.6 temperature anomaly of +0.51ºC (+0.92ºF) series (Brohan and −0.8 −1.0 and +0.11ºC (+0.20ºF), ranked ninth and others, 2006). Values are −1.2

Difference (°C) from 1961−1990 1860 1880 1900 1920 1940 1960 1980 2000 seventeenth, respectively. simple area-weighted averages. (c) Southern hemisphere 0.8 The global average temperature in 2008 was (Source: Met Office Hadley 0.6 0.4 slightly lower than for the previous years Centre, UK, and Climatic 0.2 of the twenty-first century, owing in part to Research Unit, University of 0.0 −0.2 the moderate-to-strong La Niña that devel- East Anglia, UK) −0.4 oped in the latter half of 2007. The global −0.6 −0.8 mean temperature anomaly in January 2008 −1.0

Difference (°C) from 1961−1990 1860 1880 1900 1920 1940 1960 1980 2000 (+0.05ºC/+0.09ºF) was the lowest recorded since February 1994 (–0.09ºC /–0.16ºF).

Figure 2. Global ranked surface 0.5 temperatures for the 1998 2005 2003 warmest 50 years. 0.6 2002 0.0 2004 2006 2007

Inset shows global 2001

ranked surface 1997 −0.5

temperatures 2008 1995 from 1850. The size 0.4 1999 0 50 100 150 of the bars indicates the 1990 2000 Rank 1991 1983

95 per cent confident 1994 1987 1988 1996 limits associated with 1981 1944 1993 1980 1989 1941 each year. The source 1878 1877 1992 1973 1977

0.2 1979 1939 data are blended land 1940 1986 1938 1982 1945 1969 1937 1984 surface air temperature 1943 1985 1958 1962 1942 1961 1963 1978 and SST from the 1990−2008 1972 HadCRUT3 series 1970−1989 0.0 (Brohan and others, 1950−1969 2006). Values are simple

Anomaly (°C) with respect to 1961−1990 1930−1949 area-weighted averages 1910−1929 for the whole year. 1890−1909 (Source: Met Office Hadley −0.2 1850−1889 Centre, UK, and Climatic Research Unit, University of 10 20 30 40 50 East Anglia, UK) Rank

90N Figure 3. Global field of land surface and sea surface temperature 60N anomalies (°C, relative to 1961–1990) for 2008 (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

All temperature values have uncertain- between +1ºC and +3ºC); conversely, part of ties, which arise mainly from gaps in data the United States and Canada experienced coverage. The size of the uncertainties is such slightly cooler than average temperatures. In that, for example, although 2008 is nominally the southern hemisphere, over the ocean and the tenth warmest year on record, it could lie south of 45° latitude, the temperatures were anywhere between the seventh and fourteenth mostly below average. warmest years. Europe and Asia Since the beginning of the twentieth century, A large geographical area, including north- the global average surface temperature has western Siberia and part of the Scandinavian risen by 0.74°C, although this increase has not region, recorded a remarkably mild winter. been continuous. The linear warming trend January and February were very mild in over the past 50 years (0.13°C per decade) is most of Europe. Monthly mean temperature nearly twice that for the past 100 years. anomalies for these months exceeded +7°C in some places in Scandinavia. In Note: Following established practice, WMO global temperature analyses are based on two different datasets. One is most parts of Finland, Norway and Sweden, the combined dataset maintained by the Met Office Hadley winter 2007/2008 was the warmest recorded Centre, UK, and the Climatic Research Unit, University of since the beginning of measurements. The East Anglia, UK. The other is maintained by the United previous mildest winter in Finland was the States Department of Commerce’s National Oceanic and Atmospheric Administration. Both centres use improved 1924/1925 winter, more than 80 years ago. temperature analyses, but different methodologies. These Large parts of Western Europe, including differing methodologies may result in small differences in the United Kingdom, France, Germany, the global ranking. Netherlands, Switzerland and Austria, had an exceptionally sunny February with some Regional temperature anomalies areas recording over double their monthly average sunshine duration. The United In 2008 most parts of the world experienced Kingdom experienced its sunniest winter yet again a year of above-average tempera- since 1929. tures. The northern hemisphere, particularly Europe, Asia and the North Atlantic, had the The boreal winter was remarkably cold for a largest anomalies (the anomalies reached large part of Asia, extending eastward from

Arctic sea ice Second lowest extent Alaska on record in September, Second highest winter (2007/2008) Northern hemisphere snow cover extent behind September 2007 Eurasian snow cover extent snowfall in the past 3 decades Severe winter weather across much of China and central Asia was Largest January snow cover extent on record. no-Scandinavia in Bethel; in Nome, Fen attributed to Eurasia’s largest January snow cover extent on record. March 2008 had the second least snow cover extent, United Kingdom Most parts of Norway, Sweden second snowiest 2008 boreal summer ranked However, unusually warm temperatures led to Eurasia’s smallest snow cover behind 1990. and Finland experienced their season, behind the as one of the top 10 wettest extent during March, April and boreal spring 2008. warmest winter ever recorded. 1994/1995 season United States Canada summers since records began Heavy rain and flooding Third snowiest winter in Toronto in 1914 for the country. across the Midwest in since snow measurement records Uzbekistan North-west Pacific typhoon season United States June; the worst floods began 70 years ago Spain and Portugal Northern Europe January coldwave, with lowest Near average activity 2008 was one of the top 10 years since 1993 Worst drought in more Powerful storms temperature in 40 years 22 storms, 11 cyclones for tornado-related fatalities since United States than a decade in Spain; with wind gusts up In May, four named tropical cyclones formed over the China reliable records began in 1953. Third worst fire season, worst winter drought in to 160 km/h (March) sea around or east of the Philippines. This was the Tropical Storm Fay (August) Worst severe winter weather behind 2006 and 2007; Portugal since 1917 highest number in May since 1980. Maximum winds 100 km/h Middle East region in 5 decades (January); over persistent drought across Hurricane Norbert (October) The first storm in recorded Hurricane Omar (October) Heaviest snowfall in January in the 78 million people affected by the the western and south- Maximum winds 220 km/h history to strike Florida (or Maximum winds 205 km/h Islamic Republic of Iran in more than a freezing temperatures and heavy snow. eastern United States Most powerful 2008 East Pacific hurricane; any state) four times First hurricane to strike the Leeward decade. Snow fell for the first time in Tibet was struck by the worst snowstorm Typhoon Hagupit (September) living memory in Baghdad, Iraq. About the first October hurricane to make Islands from the west since 1999 Northern Africa in living memory during October. Maximum winds 220 km/h landfall on the Baja Peninsula since 1968 50 people died and over 15 000 animals The worst typhoon to hit China’s Guangdong Hurricane Hurricane Ike (September) Heavy rain and flooding perished due to the cold weather. Parts India province in more than a decade Paloma (Nov.) Maximum winds 230 km/h (September-November). Maximum winds 230 km/h Third most destructive US of Turkey experienced their coldest Mumbai, Maharashtra Hawaii Extreme precipitation in January nights in nearly 5 decades. Heavy rain and flooding (February). Second strongest November landfalling hurricane after had its heaviest rainfall Typhoon Fengshen (June) Morocco affected tens of Maximum winds 205 km/h A new daily record was set in Hilo Atlantic hurricane on Katrina (2005) and Andrew (1992) in 7 years (June). thousands of people and The storm capsized a ferry near on 2 February when 279 mm (11 inches) record, behind Hurricane Gustav (August) caused severe infrastructure Sibuyan Island, causing Philippines’ of rain fell in 24 hours. Lenny in 1999 Maximum winds 240 km/h damage. These were the Tropical Cyclone Nargis (May) Viet Nam worst maritime disaster since 1987. Worst storm to hit Cuba in five Hurricane Bertha (July) worst floods in a century Maximum winds 215 km/h Heavy rain and East Pacific hurricane season Tropical Storm Alma (May) decades; 341 km/h wind gusts Maximum winds 205 km/h for Algeria. The most devastating cyclone to floods (October) Typhoon Neoguri (April) Near average activity Maximum winds 105 km/h registered in Paso Real San Diego, The longest-lived July strike Asia since 1991, causing the Maximum winds 175 km/h 17 storms, 7 hurricanes The farthest east tropical storm the highest in Cuba’s history Atlantic tropical storm worst natural disaster ever in Myanmar The earliest typhoon to strike to have formed in the eastern on record (17 days) China on record Pacific Ocean since 1970 ENSO North Indian Ocean cyclone season Moderate La Niña conditions transitioned Brazil Atlantic hurricane season Above average activity Above average activity into neutral phase in June. Heavy rain and flooding 7 storms, 1 cyclone Ecuador (November) affected 16 storms, 8 hurricanes Heavy rain and flooding 1.5 million people and 2008 was the first year in which there (February); worst floods resulted in 84 fatalities. was a major hurricane every month in country’s history This was the region’s from July through November. Tropical Cyclone Ivan (February) worst weather tragedy Bolivia Maximum winds 215 km/h Australia in history. One of the strongest cyclones Warmest January in the 1950–2008 Heavy rain and ever to strike Madagascar period of record. Driest May on flooding (January) record for the country. Parts of affected nearly Global tropical South Indian Ocean Australia have been experiencing 25 000 people. South-eastern Africa cyclone activity cyclone season drought conditions for over a decade. New Zealand Below average activity Flooding in Mozambique, Near average activity Chile Zimbabwe and Malawi in Major winter cyclone caused 90 storms 12 storms, 8 cyclones flash floods and widespread Worst drought Argentina, Paraguay January; worst floods ever 42 hurricanes/typhoons/cyclones wind damage across in 5 decades in and Uruguay recorded in Zimbabwe 20 “major” hurricanes/typhoons/ Australian cyclone season North Island in July. Central and Prolonged drought cyclones Near average activity significantly affected southern 9 storms, 4 cyclones Chile agriculture. Some areas experienced their worst drought in over 50 years. South Pacific tropical cyclone season Below average activity 7 storms, 3 cyclones Antarctic ozone hole: 27.2 million km² at its peak in mid-September; fifth largest on record since satellite records began in 1979; exceeded the 2007 hole

Turkey to China. Some places in Turkey expe- central and north-west Asia. In addition, several rienced their coldest January nights in nearly heatwaves occurred in south-eastern Europe 50 years. This extreme cold weather caused and the Middle East during April. In Crete, hundreds of casualties in Afghanistan and Greece, the temperature of 37.4°C recorded China. In January the mean temperatures on 22 April was the highest ever measured reached anomalies between –4ºC and –10ºC on the island for that month. Summer was around this region. Spring was very warm in also warmer than average in most parts of large parts of Europe and Asia, especially in Europe and Asia, as was autumn, particu- March when anomalies were above +5ºC in larly November, when significant temperature

anomalies ranging between +3°C and +5°C records were set in Toronto on 7 and 8 January Figure 4. Significant were recorded from eastern Europe to central when temperatures soared to 14°C. February climate anomalies and Asia. was much colder than average across Canada, events in 2008 Alaska and the northern United States, with (Source: National Climatic North America average daily temperatures ranging from Data Center, NOAA, United The year started warmer than normal across 4.0°C to 5.0°C below normal in some areas. States) Canada and the central-eastern United States, In spring, temperatures were cooler than but cooler than average in the western United average in most parts of the United States States. Two daily maximum temperatures and Canada, and warmer than average in

Mexico. During the summer season, tem- temperature records in part due to an unusual peratures were near normal except in eastern heatwave at the end of the month in central Canada. November was also particularly Argentina. mild over Canada and the western part of the United States. Australia In Australia, the year started with the hottest South America January since 1950. An exceptionally pro- Between January and April, above-normal longed heatwave affected much of southern temperatures predominated over southern Australia in March. For example, Adelaide had South America; conversely, below-normal its longest running heatwave on record, with temperatures were recorded in the central 15 consecutive days of maximum temperatures and north-western part of the region. During above 35°C, well in excess of the previous the same period, southern Argentina and record of 8 consecutive days. Despite this, the Chile were affected by persistent atmospheric rest of the austral autumn was characterized, in blocking situations that brought very hot much of the country, by above-average daytime weather to the area. February was particu- and below-average overnight temperatures. larly warm throughout this region. Many In Queensland, the first ever sub-zero March locations recorded the warmest February in minimum (–0.2°C) was recorded at Stanthorpe, 50 years, with daily maximum tempera- while Kalumburu (Western Australia) and tures reaching between 35°C and 40°C, well Kowanyama (Queensland) had 60 or more above the average, which ranges between consecutive below-normal nights, extending 20°C and 28°C. from early April to early June. September and October were very warm months ranking, May was colder than average especially with the two-month combined period, second because of an early Antarctic air mass out- behind 1988. break that affected southern South America, particularly central and northern Argentina, where the minimum temperature dropped Global precipitation below –6°C in some locations, breaking annual absolute minimum temperature records. In 2008, global precipitation over land Conversely, mean July temperatures were was slightly above the 1961–1990 average. more than +3°C above average in large parts Precipitation throughout the year was variable of Argentina, Uruguay, Paraguay, south-east in many areas. Less than average conditions Bolivia and southern Brazil, making it the were observed across the western and warmest July in the past 50 years for many south-central contiguous United States; south- locations. November also broke historical western Alaska and the Hawaiian Islands;

Figure 5. Monthly air surface temperature anomalies showing departures in degrees Celsius, 1961–1990 base for January 2008 over Europe (Source: Deutscher Less than –4 Wetterdienst, Germany) –4 to –3 –3 to –2 –2 to –1 –1 to 0 0 to 1 1 to 2 2 to 3 3 to 4 More than 4

90N Figure 6. Annual precipitation anomalies for global land areas for 60N 2008; gridded 1.0-degree raingauge-based analysis as normalized 30N departures in mm/month from normal focusing on 1951–2000 base period 0 (Source: Global Precipitation Climatology Centre, Deutscher Wetterdienst, 30S Germany).

60S

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

–70 –50 –30 –10 10 30 50 70

south-eastern Africa; southern Europe; half of 2007. The precipitation index used in northern India; and parts of Argentina, Uruguay, Argentina, as shown in Figure 7 for the north- eastern Asia and southern Australia. Most of east region, shows the severity and duration Europe, western Africa, the north-eastern and of this drought. This drought caused some central contiguous United States, parts of damage to agriculture, livestock and water northern South America, south-eastern Asia resources. During 2008, the total precipita- and northern Australia experienced wetter tion was between 40 and 60 per cent below than average conditions. normal and many locations recorded one of the driest years since 1900.

Drought In south-eastern Australia dry conditions reinforced long-term drought over much At the end of July, most parts of the south-east of that region. This was the third consecu- of North America were classified as having tive year in which the September–October moderate to exceptional drought conditions, based on the United States Drought Monitor. The continuous dry conditions across northern Figure 7. Standardized and central California resulted in numerous 24S SPI – 12 months Precipitation Index for large wildfires. Extremely wet 2.0 2008 (SPI 12) for the Very wet 1.5 centre-east and north- In Canada, southern British Columbia expe- Wet rienced its fifth driest period in 61 years. In 1.0 east regions of Argentina 30S Slightly wet Europe, Portugal and Spain experienced their 0.5 (Source: National Normal worst winter drought in decades. –0.5 Meteorological Service, Slightly dry –1.0 Argentina) Dry South America, including the centre-east –1.5 36S Very dry and north-east of Argentina, and a large –2.0 part of Uruguay, Paraguay and southern Extremely dry Brazil, was particularly hit by a severe and www.smn.gov.ar prolonged drought, which started in the latter 66W 60W 54W

period was exceptionally dry. These condi- flooding that affected Missouri and southern tions exacerbated severe water shortages in Indiana. During June, 78 stations reported the agriculturally important Murray–Darling their wettest day of any June and 15 of Basin, resulting in widespread crop failures these stations set a new all-time record for in the area. the wettest 24-hour period for any month. Also, 2008 was one of the top 10 years for tornado-related fatalities (123) since reliable Extreme storms and flooding records began in 1953. According to statistics, 2 192 tornadoes were recorded during the In January, 1.3 million square kilometres (km2) year, well above the 10-year average of 1 270. in 15 provinces in southern China were cov- ered by snow. Persistent low temperature and In Germany, between May and September, icing affected the daily lives of millions of a large number of strong thunderstorms people who suffered not only from dam- with heavy rain, tornadoes and hailstorms age to agriculture, but also from disruptions were observed, causing some casualties and in transport, energy supply and power significant damage. transmission. Sub-Saharan Africa, including West and In Canada, several all-time snowfall records East Africa, was affected by heavy rains, were set during winter, reaching more than which caused the worst-ever recorded 550 centimetres (cm) in many locations, flooding in Zimbabwe and affected more than including Quebec City. In Toronto, it was the 300 000 people in West Africa during the third snowiest winter on record for the past monsoon season. 70 years. At the end of January, Prince Edward Island was struck by one of the worst ice In northern Africa, heavy and extended storms in decades. rainfall during the September–November period affected Algeria and Morocco, caus- In the United States, heavy April rainfall, ing important infrastructure damage and combined with previously saturated ground several casualties. Extreme rainfall intensities and snowmelt, resulted in widespread major with up to 200 millimetres (mm) of rainfall

Figure 8. Australian rainfall deciles for the year 2008. Deciles are calculated relative to the period 1900–2008, Rainfall decile ranges with distribution based on gridded data from the Highest on record National Climate Centre. Very much (Source: Commonwealth of 10 above average

Australia, Australian Bureau 8–9 Above average of Meteorology, Australia) 4–7 Average

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

in less than six hours were recorded in the May, killing more than 70 000 people and northern provinces of Morocco. Within the destroying thousands of homes. Nargis was same climate anomaly context and period, the most devastating cyclone to hit Asia intense rainfall was also recorded in south- since 1991 and resulted in the worst natural western Europe. In Valencia, Spain, a total disaster on record for Myanmar. rainfall of 390 mm was recorded in 24 hours, of which 144 mm was recorded in less than A total of 16 named tropical storms formed 1 hour. In France, heavy and intense rains in the Atlantic, including 8 hurricanes, 5 of affected several locations from 31 October to which were major Category 3 or higher, 2 November. In those three days, total rainfall compared with the long-term average of reached 500 mm in some locations, which 11 tropical storms, 6 hurricanes, 2 which were caused severe flooding and flash floods, Category 3 or higher. The 2008 Atlantic hur- particularly in the central and east-central ricane season was devastating, with many parts of the country. casualties and widespread destruction in the Caribbean, Central America and the United Several major rain events affected eastern States. For the first time on record, six con- Australia in January and February, causing secutive tropical cyclones (Dolly, Edouard, significant flooding, particularly in Queensland. Fay, Gustav, Hanna and Ike) made landfall In November, widespread heavy rains occurred on the United States, and a record of three across most of the continent, ending an major hurricanes (Gustav, Ike and Paloma) extremely dry period in central Australia. hit Cuba. Hanna, Ike and Gustav were the Associated severe thunderstorms caused deadliest hurricanes of the season, causing damage from winds, hail and flash floods in several hundred casualties in the Caribbean, many places. including 500 deaths in Haiti.

In southern Asia, including India, Pakistan and In the East Pacific, 17 named tropical storms Viet Nam, heavy monsoon rains and torrential were recorded, of which 7 evolved into hur- downpours produced flash floods, killing more ricanes and 2 into major hurricanes, compared than 2 600 people, and displacing 10 million with averages of 16, 9 and 4, respectively. people in India. In the western North Pacific, 22 named tropi- In western Colombia, continuous above- cal storms were recorded; of these, 11 were normal rainfall resulted in severe flooding classified as typhoons compared with the and landslides that affected at least half a long-term averages of 27 and 14, respectively. million people and caused extensive damage The Philippines, Cambodia, the Lao People’s during the second half of the year. Democratic Republic, Thailand, Viet Nam and south-eastern China were severely affected In Southern Brazil, intense rainfall affected by these events. For the first time since 2001, Santa Catarina state from 21 to 24 November, no named tropical cyclones made landfall in causing severe flooding and deadly mudslides, Japan during the year. which affected 1.5 million people and resulted in more than 80 casualties. During this period, In the broader Australian region, tropical more than 500 mm of rainfall was recorded, cyclone numbers during the 2007/2008 sea- including more than 200 mm of rainfall in son were close to normal, with a total of 24 hours (breaking historical records for 10 systems. However, it was a quiet season 24-hour rainfall), for example, at Blumenau, for landfalls and intense systems. Balneário Camboriú, São Francisco do Sul, Itapoá and Biguaçú. Weakening of La Niña

Tropical cyclones The first quarter of 2008 was characterized by a La Niña event of moderate to strong The most deadly tropical cyclone recorded intensity, which began in the second half of in 2008 was Nargis, which developed in the 2007 and prevailed through May 2008. The North Indian Ocean and hit Myanmar in early large area of cool surface waters over the

Figure 9. Area-averaged upper-ocean heat 0.9 content anomalies (°C) 0.6 in the upper 300 m of the equatorial Pacific 0.3 (5°N–5°S, 180º–100ºW). 0 Heat content anomalies are computed as –0.3

departures from the (°C) 1982–2004 base period –0.6 pentad means. –0.9 (Source: Climate Prediction Center, National Centers for –1.2 Environmental Prediction, NOAA, United States) –1.5

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 2008

bulk of the central and eastern equatorial with the cooler than normal surface waters, Pacific, combined with warmer than normal generally indicating La Niña conditions, conditions in the equatorial western Pacific, across the tropical Pacific towards the end of represented typical La Niña forcing on the global the year. atmosphere. La Niña conditions gradually weakened from their peak strength in February, and near-neutral conditions prevailed during Antarctic ozone hole larger than in 2007 most of the latter half of 2008. However, cold sea surface temperatures developed in The ozone hole area reached a maximum of December in the central and eastern equatorial 27 million km2 on 12 September. This is less Pacific. Atmospheric wind patterns coupled than in the record years of 2000 and 2006

Figure 10. Ozone hole 35 area with respect to 1999 220 DU (Dobson Unit) in 2000 30 2001 the southern hemisphere 2002 from August to December 2003 for the years 1999–2008; 25 2004 2005 observations made by 2006 GOME and SCIAMACHY 20 2007 (Source: Royal Netherlands 2008 Meteorological Institute) 15

10 Million square km

0 Aug Sep Oct Nov Dec

10 (more than 29 million km2), but larger than in Average sea-ice extent over the month 2007 (25 million km2). The variation in the size of September, a standard measure in the of the ozone hole from one year to another scientific study of Arctic sea ice, was can be explained, to a large extent, by the 4.67 million km2. The record monthly low, set meteorological conditions in the stratosphere, in 2007, was 4.3 million km2. As the ice was as ozone depletion becomes more severe if the thinner in 2008, its overall volume was less stratosphere is cold. Temperature conditions than that in any other year. A remarkable occur- in the 2008 Antarctic stratospheric vortex were rence in 2008 was the dramatic disappearance colder than in 2007 but warmer than in 2006. of nearly one quarter of the massive ancient Over the next few years, the variation in the ice shelves on Ellesmere Island. The season severity of ozone hole will be governed by strongly reinforces the 30-year downward inter-annual changes in meteorology rather trend in Arctic sea-ice extent. than changes in ozone depleting substances, whose decline is quite slow. For the first time in recorded history, the navigable deep-water routes of the fabled Northwest Passage over the top of North Arctic sea ice down to second-lowest extent America, and the Northeast Passage over the top of the Russian Federation, were Arctic sea-ice extent during the 2008 melt simultaneously free of ice. The year 2008 season dropped to its second-lowest level marked the third consecutive summer that since satellite measurements began in 1979, ships could easily navigate the Northwest reaching the lowest point in its annual cycle Passage without hitting or being blocked by of melt and growth on 14 September 2008. sea ice.

Figure 11. Sea-ice extent for September 2008 and September 2007; the magenta line indicates the long- term median from the 1979–2000 base period. The sea-ice extent in September 2008 was 4.67 million square kilometres, reaching the second lowest value after the record of 4.28 million square kilometres observed in 2007. (Source: National Snow and Ice Data Center, United States)

11 Benefits for climate monitoring and assessment of data rescue activities by Phil Jones, Climatic Research Unit, School of Environmental Sciences, University of East Anglia, UK

In most regions of the world there are longer is that the longer records enable trends and instrumental records than apparent in a cur- other analyses to be more extensive, placing sory search of the website or archives of a recent records and extremes in the longer National Meteorological and Hydrological context. Longer climatic series also provide Service (NMHS). In most cases this results instrumental data for more extensive calibra- from the NMHS not yet having digitized all the tion of natural and documentary proxies, both meteorological data in its archives. In many of which have the potential for extending the cases the records pre-date the founding of climatic history further back in time. Longer the Service, whereas in others they pre-date observational data provide better coverage the founding of the country. It is important (in both space and time) for extended rea- that these early records, which were often nalysis projects, planned to begin from the taken with meticulous care by early scien- late nineteenth century. Lastly, longer records tists and medical doctors, be digitized and are useful for assessing impacts of climate made available for climatological use. These change over more extensive time frames early records are generally to be found in than just the recent past. The following two national or learned society archives, some- examples discuss the above for northern times located in the archives of an earlier and western Europe. They illustrate what has colonial power. Present-day scientists owe been achieved through more extensive digital their forebears much gratitude for taking these instrumental data. early measurements with meticulous care and diligence. Given this effort, it would be a Longer records for the assessment shame if they were left to collect more dust in of proxy evidence an archive. Longer climatic reconstructions require infor- Extending climatic series brings a number of mation from natural (for example, trees and scientific benefits, both to the NMHS and to ice cores) and documentary (written archives) the climatological research community in the proxy material. These proxy records must use country and in the region. The primary benefit instrumental records to calibrate the proxy

Comparison of instrumental and proxy 6 April–May temperatures: observations (red), ice break-up dates (blue) records developed for northern Fennoscandia 4 (using the instrumental temperature series for 2 Haparanda, developed by Klingbjer and Moberg 0 (2003), which extends –2 back to 1800); top panel: April–May instrumental –4 temperatures (red), estimated temperatures 16 based on ice break-up dates (blue); bottom 15 panel: June–August 14 instrumental 13 temperatures (red), 12 calibrated temperatures based on tree-ring 11 width and density data 10 (green, from near Lake 9 June–August temperatures: observations (red), tree-ring series (green) Torneträsk) 1700 1750 1800 1850 1900 1950 2000

12 source. In many regions, calibration is ham- potential length anywhere in the world are pered by the lack of long instrumental records. Paris and London. At both sites, near-continuous In Europe, however, it is generally possible to daily pressure records have been taken since assess the quality of possible reconstructions, the late seventeenth century. For Paris, a especially the longer decadal-timescale details, complete record has been developed back to for almost 200 years. The figure shows exam- 1677, missing only most of the years in the ples of such calibration exercises using a long 1720s and 1730s. For London, the record is instrumental record developed for northern complete from 1692, missing only the years Fennoscandia. Both proxy series show good between 1717 and 1722. Despite these short replication of instrumental temperatures at gaps, a very useful approximation to the winter the inter-annual and decadal timescales. NAO has been developed back to 1692.

Extensions of the North Atlantic Oscillation References

The longest record of the winter North Atlantic Jones, P.D., R. Jónsson, T and D. Wheeler, 1997: Oscillation (NAO), back to 1820, has been Extension to the North Atlantic Oscillation derived by Jones and others (1997) based on using early instrumental pressure observations pressure data from Gibraltar and Reykjavik. from Gibraltar and SW Iceland. International As the NAO is essentially a measure of the Journal of Climatology, 17:1433–1450. westerly wind strength over western Europe, two long well-located pressure records would Klingbjer, P. and A. Moberg, 2003: A composite provide a good surrogate for the more distant monthly temperature record from Tornedalen locations in Iceland and southern Iberia or the in northern Sweden, 1802–2002, International Azores. The two locations with the greatest Journal of Climatology, 23:1465–1494.

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