The Global Climate 2001–2010 a Decade of Climate Extremes Summary Report

the global climate 2001 – 2010 A decade of climate extremes SUMMARY REPORT

WMO-No. 1119 WMO-No. 1119 © World Meteorological Organization, 2013

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The findings, interpretations and conclusions expressed in WMO publications with named authors are those of the authors alone and do not necessarily reflect those of WMO or its Members. THE GLOBAL CLIMATE 2001–2010 A DECADE OF CLIMATE EXTREMES SUMMARY REPORT

Foreword

The first decade of the 21st century was the gathering of data from the world’s leading warmest decade recorded since modern climate data, monitoring and research measurements began around 1850. It saw centres. These data, together with climate above-average precipitation, including one information collected through a unique survey year – 2010 – that broke all previous records. among the world’s National Meteorological It was also marked by dramatic climate and and Hydrological Services, were also used weather extremes such as the European to produce the decadal report The Global heatwave of 2003, the 2010 floods in Pakistan, Climate 2001–2010. hurricane Katrina in the United States of America (USA), cyclone Nargis in Myanmar A decadal perspective makes it possible to and long-term droughts in the Amazon Basin, assess trends and anticipate the future. It can Australia and East Africa. also inform efforts to develop operational climate services that provide information and Many of these events and trends can be forecasts for decision-making in agriculture, explained by the natural variability of the climate health, disaster risk, water resources and other system. Rising atmospheric concentrations of sectors. These efforts are being coordinated greenhouse gases, however, are also affecting through the WMO-led Global Framework for the climate. Detecting the respective roles Climate Services. being played by climate variability and human- induced climate change is one of the key To learn more about the 2001–2010 decade of challenges facing researchers today. extremes, including the detailed results of the WMO survey of countries, you are strongly The World Meteorological Organization encouraged to read the complete technical (WMO) is proud to be a major contributor to report (WMO-No. 1103), which is available international efforts to better understand our online on the WMO website. climate. We sponsor or co-sponsor leading research and observation programmes, notably the WMO Global Atmosphere Watch, the World Climate Research Programme, the Global Climate Observing System and the Intergovernmental Panel on Climate Change.

We also produce an annual statement – Status of the Global Climate – based on the WMO Climate System Monitoring network. This (M. Jarraud) international collaboration facilitates the Secretary-General 1. Climate variability and climate change conditions returned from late 2007, a brief El Niño appeared from June 2009 and then a The Earth’s climate fluctuates over seasons, strong La Niña episode started in mid-2010. decades and centuries in response to both This short-term natural variability may have natural and human variables. Natural climate masked some of the effects of long-term variability on different timescales is caused by climate change. cycles and trends in the Earth’s orbit, incoming solar radiation, the atmosphere’s chemical The closely related Arctic Oscillation and North composition, ocean circulation, the biosphere Atlantic Oscillation often affect the northern and much more. hemisphere winter. Since the 1990s, these two oscillations have remained mostly in a positive Climate change refers to long-term changes in phase, which is associated with warmer the average state of the climate and can also and wetter winters in northern and central be due to natural factors. The rapid changes Europe and the eastern USA, drier winters in that have occurred since the middle of the past the Mediterranean and cold, dry conditions century, however, have been caused largely over northern Canada and Greenland. The by humanity’s emissions of greenhouse gases winter of 2009/2010, however, saw extremely into the atmosphere. Other human activities negative phases with low winter temperatures also affect the climate system, including in northern and central Europe. emissions of pollutants and other aerosols, and changes to the land surface, such as Unlike these natural back-and-forth urbanization and deforestation. oscillations, human-caused climate change is trending in just one direction. This is because Short-term natural climate variability can often atmospheric concentrations of carbon dioxide, be linked to recurring patterns of atmospheric methane, nitrous oxide and other greenhouse pressure and ocean circulation. El Niño and gases are increasing steadily, due to human La Niña episodes, for example, result from activities. According to the WMO Greenhouse rapid changes in the sea-surface temperature Gas Bulletin, global-average atmospheric in the equatorial Pacific Ocean. They influence concentrations of carbon dioxide rose to weather patterns around the world through 389 ppm1 in 2010 (an increase of 39 per cent the subsequent large-scale interactions compared to pre-industrial times), methane to and transfers of heat in the coupled ocean- 1 808.0 ppb1 (158 per cent) and nitrous oxide atmosphere system. Other patterns affect to 323.2 ppb (20 per cent). This changing the climate by strengthening or weakening composition of the atmosphere is causing high-altitude air currents known as jet streams. the global average temperature to rise, which, in turn, exerts a significant influence on the The decade 2001–2010 did not experience hydrological cycle and leads to other changes a major El Niño event, which is normally in climate and weather patterns. associated with a warming of the global climate (as occurred for example in the Humanity’s emissions of chlorofluorocarbons then-record warm year of 1998). La Niña and and other chemicals have also changed the neutral conditions prevailed until mid-2006, ______followed by a brief El Niño. Cool La Niña 1 ppm = parts per million; ppb = parts per billion

Table 1. Mixing ratio of Increase since pre- 2010 1991–2000 2001–2010 carbon dioxide, methane industrial times and nitrous oxide in Carbon dioxide 389 ppm 39% 361.5 ppm 380 ppm 2010 and the decadal Methane 1 808 ppb 158% 1 758 ppb 1 790 ppb values for 1991–2000 and 2001–2010 Nitrous oxide 323.2 ppb 20% 312.2 ppb 319.7 ppb

2 atmosphere by damaging the stratospheric the 1961–1990 global average of +14.0°C and ozone layer that filters out harmful ultraviolet +0.21 ± 0.1°C above the 1991–2000 global radiation. Fortunately, the phase-out of ozone- average. It is 0.88°C higher than the average depleting substances under the Montreal temperature of the first decade of the 20th Protocol should allow the ozone layer to recover century (1901–1910). in a few decades. The Antarctic ozone hole is believed to influence the Southern Annular A pronounced increase in the global Mode oscillation and thus the regional climate. temperature occurred over the four decades Meanwhile, emissions of reactive gases (such 1971–2010. The global temperature increased as nitrogen oxides and sulphur dioxide) and at an average estimated rate of 0.17°C per aerosols (such as dust and black carbon) decade during that period, while the trend also interact with the climate, for example by over the whole period 1880–2010 was only increasing the health impacts of heatwaves. 0.062°C per decade. Furthermore, the increase of 0.21°C in the average decadal 2. The warmest decade temperature from 1991–2000 to 2001–2010 is larger than the increase from 1981–1990 The period 2001–2010 was the warmest to 1991–2000 (+0.14°C) and larger than for decade on record since modern any other two successive decades since the meteorological records began around the beginning of instrumental records. year 1850. The global average temperature of the air above the Earth’s surface over the Nine of the decade’s years were among 10-year period is estimated to have been the 10 warmest on record. The warmest 14.47°C ± 0.1°C. This is 0.47°C ± 0.1°C above year ever recorded was 2010, with a mean

Temperature anomaly (ºC)

Warmest/least Domain Warmest/coldest 2001–2010 (A) warm year during decade on record (C) 2001–2010 (B) 2007 (+0.95ºC) 2001–2010 (+0.79ºC) Land +0.79ºC 2001 and 2004 1881–1890 (–0.51ºC) (+0.68ºC) Global 2003 (+0.40ºC) 2001–2010 (+0.35ºC) Table 2. Surface Ocean +0.35ºC temperature anomalies 2008 (+0.26ºC) 1901–1910 (–0.45ºC) with respect to 1961– 2010 (+0.54ºC) 2001–2010 (+0.47ºC) Land-ocean +0.47ºC 1990: over the globe, 2008 (+0.35ºC) 1901–1910 (–0.45ºC) northern hemisphere and 2007 (+1.13ºC) 2001–2010 (+0.90ºC) southern hemisphere Land +0.90ºC 2004 (+0.76ºC) 1881–1890 (–0.52ºC) for 2001–2010 (A), Northern 2005 (+0.47ºC) 2001–2010 (+0.41ºC) annual extreme values Ocean +0.41ºC for 2001–2010 (B) and hemisphere 2008 (+0.33ºC) 1901–1910 (-0.39ºC) decadal extreme values 2010 (+0.69ºC) 2001–2010 (+0.60ºC) Land-ocean +0.60ºC for 1881-2010 (C) (source: 2008 (+0.53ºC) 1901–1910 (-0.38ºC) UK Met Office and US 2005 (+0.67ºC) 2001–2010 (+0.48ºC) National Oceanic and Land +0.48ºC 2001 (+0.34ºC) 1901–1910 (–0.53ºC) Atmospheric Administration Southern 2002 (+0.34ºC) 2001–2010 (+0.29ºC) (NOAA) for global analyses Ocean +0.29ºC combined; NOAA-National hemisphere 2008 (+0.20ºC) 1901–1910 (–0.51ºC) Climate Date Center 2009 (+0.38ºC) 2001–2010 (+0.33ºC) Land-ocean +0.33ºC (NCDC) for the northern and 2008 (+0.24ºC) 1901–1910 (–0.51ºC) southern hemispheres)

3 temperature anomaly estimated at 0.54°C particularly in 2010, when records were above the 14.0°C baseline, followed closely broken by over +1°C in some areas. At the by 2005. The least warm year was 2008, with national level, a large majority of countries an estimated anomaly of +0.38°C, but this responding to the WMO survey reported was enough to make 2008 the warmest La that they experienced their warmest Niña year on record. decade on record. Many geographically large countries and regions saw decadal The 2001–2010 decade was also the temperature anomalies over 2001–2010 that warmest on record for both land-only and exceeded +1°C relative to the long-term ocean-only surface temperatures. The average of 1961–1990. warmest worldwide land-only surface-air temperature was recorded in 2007, with Europe experienced above-normal a temperature anomaly of +0.95°C. The temperatures between 2001 and 2009, warmest worldwide ocean-only surface with 2007 the warmest year on record for temperature was measured in 2003, with large parts of the region. Europe, including an anomaly of +0.4°C above the 1961–1990 Greenland, saw a median temperature average. This is consistent with climate- anomaly of +1.0°C for the decade. Greenland change science, which projects that the recorded the world’s largest decadal mean ocean surface will warm more slowly than temperature anomaly of +1.71°C. the land because much of the additional heat will be transported down into the ocean Much of Asia also saw anomalies exceeding depths or lost through evaporation. +1°C over the course of the decade, including China, the Islamic Republic of Iran, Mongolia When considered region by region, most and the Russian Federation. For the whole areas of the world also experienced above- continent the median temperature anomaly average temperatures during the decade, of the decade was +0.84°C. Figure 1. Decadal global combined surface-air temperature over 14.500 14.47 land and sea-surface temperature (°C) obtained from the average over the three 14.26 independent datasets 14.225 maintained by the UK Met Office Hadley Centre and 14.12 the Climatic Research Unit, University of East 13.95 13.95 Anglia, in the United 13.950 13.92 13.93 Kingdom (HadCRU), 13.89 NOAA-National Climatic

Data Center (NCDC) Global temperature (°C) 13.76 and the US National 13.68 13.67 Aeronautics and Space 13.675 13.64 Administration-Goddard 13.59 Institute for Space Studies (NASA-GISS). The horizontal grey line indicates the long- 13.400 term average value for 1881 1891 1901 1911 1921 1931 1941 1951 1961 1971 1981 1991 2001 1961–1990 (14°C). 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

4 0.6 Figure 2. Annual global surface temperature anomaly for 1950–2010 0.5 with reference to the 1961–1990 base period, 0.4 indicating the years with La Niña events (blue) 0.3 and those with El Niño events (red) (source: HadCRU, NOAA-NCDC 0.2 and NASA-GISS)

0.1

–0.1

–0.2

–0.3 1950 1956 1962 1968 1974 1980 1986 1992 1998 2004 2010

Africa experienced warmer-than-normal highest anomaly of +1.3°C, making 2001–2010 conditions in every year of the decade. The the country’s warmest decade. highest temperature anomalies occurred in countries north of the Equator. South of the In Oceania, Australia, French Polynesia, New Equator, Angola, Botswana, Madagascar, Caledonia, New Zealand and Tonga reported Namibia, South Africa and Zimbabwe positive temperature anomalies in the last confirmed temperature anomalies in the two decades, with a median value of +0.34°C range of +0.5°C to +1°C. The median for the 2001–2010 decade. In Australia, the temperature anomaly of the decade in Africa largest country of the region, 2001–2010 was was +0.7°C the warmest decade ever, with an anomaly value of +0.48°C. The largest country in South America, Brazil, recorded the continent’s highest temperature As shown in Figures 1 and 2, the decade 2001– anomaly value of + 0.74 °C, making the decade 2010 continued the upward trend in global the warmest on record there. The median temperatures, despite the cooling effects of value of the decadal temperature anomalies multiple La Niña episodes and other natural started to turn positive in 1981–1990 and year-to-year variability. reached +0.60°C in 2001–2010. 3. Hot and cold extremes In North and Central America, Canada and the contiguous USA and Alaska, which While the average annual temperature is an together constitute by far the region’s largest important climate indicator, the temperatures land area, recorded a combined average that people experience can differ greatly temperature anomaly greater than +0.5°C. from day to day and over the course of a year On its own, Canada recorded the region’s because of natural climate variability. At the

5 Extreme events, vulnerability, exposure and were fewer deaths due to storms and floods disasters in 2001–2010 compared to 1991–2000, with decreases of 16 per cent and 43 per Monitoring and understanding extreme cent, respectively, thanks, in good part, to events is important because these events better early warning systems and increased often destroy lives and property. Extreme preparedness. events can, however, be prevented from becoming major disasters by reducing There were fewer deaths, even while people’s vulnerability and exposure. exposure to extreme events increased as populations grew and more people were liv- While databases on disasters are useful ing in disaster-prone areas. According to the for mapping the behaviour and impact of 2011 Global Assessment Report, the average extremes in various regions, the data do not population exposed to flooding every year demonstrate that the increase in observed increased by 114 per cent globally between losses is caused by an increase in the 1970 and 2010, a period in which the world’s frequency and intensity of extreme events. population increased by 87 per cent from Other factors come into play, notably the 3.7 billion to 6.9 billion. The number of increased exposure of people and property people exposed to severe storms almost to climate extremes and the improved and tripled in cyclone-prone areas, increasing increased reporting of disasters. by 192 per cent, in the same period.

Nevertheless, it is worth noting the very While the risk of death and injury from large increase (more than 2 000 per cent) in storms and floods declined, the vulnerability the loss of life from heatwaves, particularly of property increased. This is because during the unprecedented extreme heat the expansion of socio-economic and events that affected Europe in the summer infrastructural assets led to an increase in of 2003 and the Russian Federation in the the amount and value of property exposed summer of 2010. On the other hand, there to weather and climate extremes.

400 000 Casualties 1991–2000 +20% 350 000 Casualties 2001–2010 300 000 250 000 Figure 3. Impact of –16% extreme events during 200 000 2001–2010 compared 150 000 2 300% with 1991–2000: total number of lives lost. The 100 000 –43% change in per cent from 50 000 1991–2000 to 2001–2010 189% –66% is shown above the bars. 0 (data source: EM–DAT/CRED) Heat Cold Drought Storms (all) Floods Total

6 same time, human influence has probably cent (14 out of 127) of the countries reported increased the maximum temperatures of the their absolute daily minimum temperature most extreme hot nights and days and the record being observed in 2001–2010, compared minimum temperatures of cold nights and to 32 per cent in 1961–1970 and around 20 cold days. It is also more likely than not that per cent in each of the intermediate decades human-induced climate change has increased (Figure 4). the risk of heatwaves. Over the course of the 2001–2010 decade, many According to the WMO survey, a total of countries and regions suffered heatwaves at 56 countries (44 per cent) reported their highest one time or another (Figure 5). Some of the absolute daily maximum temperature record most dramatic included two severe heatwaves over the period 1961–2010 being observed in in India in 2002 and 2003, which each killed 2001–2010 compared to 24 per cent in 1991– over 1 000 people; the 2003 summer heatwave 2000, with the remaining 32 per cent spread over over much of Europe, which caused more the earlier three decades. Conversely, 11 per than 66 000 deaths; and the exceptionally

50% Highest maximum temperature 40%

30%

20%

10%

0% 1961–1970 1971–1980 1981–1990 1991–2000 2001–2010

50% Lowest minimum temperature 40%

30%

20%

10%

0% 1961–1970 1971–1980 1981–1990 1991–2000 2001–2010 50% Highest 24-h precipitation 40% Figure 4. Absolute 30% country records of the daily maximum and 20% minimum temperature and 24-hour total 10% precipitation in the last 0% five decades (source: 1961–1970 1971–1980 1981–1990 1991–2000 2001–2010 WMO survey)

7 Russian Federation As part of a blocking situation, extreme hot Europe weather conditions affected the European part of Much of Europe was affected by the Russian Federation during July and August several extreme heatwaves 2010. This led to disastrous bush fires in the Canada Moscow region. In Moscow, July mean during summer 2003. Central Canada experienced its temperatures were 7.6°C above normal, making warmest and most humid summer on it the city’s hottest month on record by more record in 2005. 2010 was the warmest Northern Africa than 2°C. A new record high temperature for the year on record for the nation as a whole During July and August 2003, within the same city of 38.2°C was set on 29 July, and it reached since records began in 1948. atmospheric pattern that affected Europe, northern 30°C or above on 33 consecutive days. Africa experienced record warmth. In Morocco new China and Japan monthly records were set in several areas. The months of August and September 2007 were extremely USA The heat was most severe in August when warm in Japan, setting a new national record of absolute several cities recorded the highest daily maximum temperature of 40.9°C. In 2010, Japan and China had A severe heatwave gripped the south-western maximum temperature ever measured. their hottest summer on record. USA during July 2005, setting numerous Some of these records were set in temperature records. Another severe heatwave Rabat (44.6°C), Kenitra (47.7°C) persisted throughout August 2007 across Southern Asia and Tangier (43.5°C). Extremely severe heatwaves hit India in 2002, 2003 the southern and central part of the USA, Pakistan and 2005. Pakistan and Bangladesh were affected with several new all-time high temperature In 2010, a pre-monsoon heatwave in May and June 2005 with maximum temperatures records established. brought a record temperature of 53.5°C Western Africa between 45ºC and 50°C and hundreds of related deaths. to Mohenjo Daro on 26 May making a Extreme heat was reported in western national record for Pakistan and the highest Africa during the boreal summer 2002. temperature in Asia since at least 1942. Abnormally high temperatures were Brazil observed in the Sahara, as high as 50.6°C, Heatwaves in Brazil from January to March 2006 were during June and July 2002. recorded and one of the highest temperatures ever measured (44.6°C) was registered in Bom Jesus on 31 January 2006. Argentina An extreme climate anomaly hit the region in late October/early South America November 2009 when an exceptional heatwave affected northern and As part of a persistent atmospheric blocking pattern, Australia an exceptionally hot February affected southern central Argentina. Unusually high temperatures of above Several heatwaves affected Australia during Argentina and Chile in 2008. Daily maximum 40°C were recorded in many places and for several consecutive this decade, with disastrous bush fires as well temperatures reached between 35°C and 40°C, days. Some annual absolute maximum temperature records were as record temperatures. During summer well above the average, which ranges broken during this period. 2009, Victoria reached its highest temperature between 20°C and 28°C. with 48.8˚C at Hopetown, the highest temperature ever recorded so far south anywhere in the world.

intense and long-lasting heatwave that struck conditions across Europe resulted in over the Russian Federation in July/ August 2010, 450 deaths. The winter of 2009/2010 was also causing over 55 000 deaths. The WMO extremely cold in the Russian Federation, North survey identifies many other abnormally America (particularly the USA) and parts of high-temperature conditions, heatwaves and Asia. Other cold waves were experienced in the temperature records around the world. Plurinational State of Bolivia in 2002, southern Africa in 2002 and 2007, Peru in 2003, Morocco Despite the record average warmth of the and Algeria in 2005, Australia in 2005, Asia in decade, cold waves continued to cause intense 2007/2008, and southern China in 2008. suffering in many countries. Coinciding with the extreme negative phase of the Arctic 4. Precipitation, floods and droughts Oscillation and North Atlantic Oscillation, the northern hemisphere endured extreme In all parts of the world, precipitation, floods winter conditions from December 2009 to and droughts vary naturally from year to February 2010. Prolonged cold and snow year and from decade to decade. In addition,

8 Russian Federation As part of a blocking situation, extreme hot Europe weather conditions affected the European part of Much of Europe was affected by the Russian Federation during July and August several extreme heatwaves 2010. This led to disastrous bush fires in the Canada Moscow region. In Moscow, July mean during summer 2003. Central Canada experienced its temperatures were 7.6°C above normal, making warmest and most humid summer on it the city’s hottest month on record by more record in 2005. 2010 was the warmest Northern Africa than 2°C. A new record high temperature for the year on record for the nation as a whole During July and August 2003, within the same city of 38.2°C was set on 29 July, and it reached since records began in 1948. atmospheric pattern that affected Europe, northern 30°C or above on 33 consecutive days. Africa experienced record warmth. In Morocco new China and Japan monthly records were set in several areas. The months of August and September 2007 were extremely USA The heat was most severe in August when warm in Japan, setting a new national record of absolute several cities recorded the highest daily maximum temperature of 40.9°C. In 2010, Japan and China had A severe heatwave gripped the south-western maximum temperature ever measured. their hottest summer on record. USA during July 2005, setting numerous Some of these records were set in temperature records. Another severe heatwave Rabat (44.6°C), Kenitra (47.7°C) persisted throughout August 2007 across Southern Asia and Tangier (43.5°C). Extremely severe heatwaves hit India in 2002, 2003 the southern and central part of the USA, Pakistan and 2005. Pakistan and Bangladesh were affected with several new all-time high temperature In 2010, a pre-monsoon heatwave in May and June 2005 with maximum temperatures records established. brought a record temperature of 53.5°C Western Africa between 45ºC and 50°C and hundreds of related deaths. to Mohenjo Daro on 26 May making a Extreme heat was reported in western national record for Pakistan and the highest Africa during the boreal summer 2002. temperature in Asia since at least 1942. Abnormally high temperatures were Brazil observed in the Sahara, as high as 50.6°C, Heatwaves in Brazil from January to March 2006 were during June and July 2002. recorded and one of the highest temperatures ever measured (44.6°C) was registered in Bom Jesus on 31 January 2006. Argentina An extreme climate anomaly hit the region in late October/early South America November 2009 when an exceptional heatwave affected northern and As part of a persistent atmospheric blocking pattern, Australia an exceptionally hot February affected southern central Argentina. Unusually high temperatures of above Several heatwaves affected Australia during Argentina and Chile in 2008. Daily maximum 40°C were recorded in many places and for several consecutive this decade, with disastrous bush fires as well temperatures reached between 35°C and 40°C, days. Some annual absolute maximum temperature records were as record temperatures. During summer well above the average, which ranges broken during this period. 2009, Victoria reached its highest temperature between 20°C and 28°C. with 48.8˚C at Hopetown, the highest temperature ever recorded so far south anywhere in the world.

because warm air can hold more moisture, it 1901, except for the 1950s (Figure 6). In Figure 5. Most is likely that climate change has influenced addition, 2010 was the wettest year ever significant heatwaves the occurrence and intensity of extreme recorded at global level. The previous and abnormally high temperature conditions precipitation events. Greater warmth also wettest years were 1956 and 2000, which, reported during speeds up the hydrological cycle, which like the second half of 2010, coincided with 2001–2010 (source: should contribute to both heavier rainfall strong La Niña events. NOAA-NCDC) and increased evaporation. The largest number of national records for 24-hour Most parts of the globe had above-normal extreme precipitation events, as reported precipitation (Figure 7). The eastern USA, in the WMO survey, occurred over the past northern and eastern Canada, and many parts two decades,1991–2010 (Figure 4). of Europe and central Asia were particularly wet. Other wetter-than-average regions were Global land-surface precipitation averaged northern and southern Brazil, Uruguay and over 2001–2010 was above the 1961–1990 northern and eastern Argentina, southern average. It was the wettest decade since Africa, Indonesia and northern Australia.

9 Figure 6. Decadal global 20 precipitation anomaly (in mm) relative to the 1961–1990 WMO 15 standard normal (source: NOAA-NCDC) 10

–5 Precipitation anomaly (mm) –10

–15

–20 1901 1911 1921 1931 1941 1951 1961 1971 1981 1991 2001 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

90N

60N

30N

Figure 7. Decadal precipitation anomalies 30S for global land areas for 2001–2010; gridded 1° raingauge-based 60S analysis as normalized departures in mm/year focusing on 1951–2000 base period (source: Global 90S 180 120W 60W 0 60E 120E 180 Precipitation Climatology Centre (GPCC), Deutscher Wetterdienst, Germany) –350 –250 –150 –50 50 150 250 350

10 Regions that experienced below-normal In other regions, cyclone activity was precipitation included the western USA generally at average or below-average and Alaska, south-western Canada, central levels. The eastern North Pacific basin saw South America, most parts of southern and 139 named storms during the decade, of western Europe, central Africa, most parts which 65 were classified as hurricanes, of southern Asia and eastern and south- slightly below the average. The majority of eastern Australia. these tropical cyclones did not make landfall and did not cause substantial damage. The According to the WMO survey, floods were 230 tropical cyclones in the North-West the most frequently experienced extreme Pacific were also slightly below average. event over the course of the decade. Eastern The most destructive of these storms was Europe was particularly affected in 2001 Durian, which struck the Philippines in 2006, and 2005, India in 2005, Africa in 2008, Asia killing more than 1 000 people and affecting (notably Pakistan, where 2 000 people died 1.5 million. and 20 million were affected) in 2010, and Australia, also in 2010. In addition, many The North Indian Ocean saw the deadliest flash floods with landslides were reported tropical cyclone recorded during the decade, by other countries. when Nargis struck Myanmar in early May 2008. More than 138 000 people were Droughts affect more people than any other reported killed or missing, eight million kind of natural disaster owing to their large people were affected and thousands of scale and long-lasting nature. The decade homes were destroyed. 2001–2010 saw droughts occur in all parts of the world. Some of the highest-impact and Extra-tropical storms can also turn into long-term droughts struck Australia (in 2002 devastating natural disasters, mainly in mid- but also in other years), East Africa (2004 latitude regions. Three major extra-tropical and 2005, resulting in widespread loss of windstorms severely affected Europe: Kyrill life and food shortages) and the Amazon struck several parts of central Europe in Basin (2010). 2007; Klaus affected southern Europe in 2009 and Xynthia struck north-western 5. Severe storms Europe in 2010. These storms caused several billions of US dollars in damage and took According to NOAA-NCDC, 2001–2010 was nearly 100 lives. According to analyses by the most active decade since 1855 for tropical the insurance company Munich Re, winter cyclones in the North Atlantic Basin. An storms in the USA and Canada in 2007 and average of 15 named storms per year was 2008 rank among the 10 costliest storms recorded, well above the 1981–2010 long-term since 1980 in terms of insured losses. average of 12 named storms per year. 6. Shrinking ice and rising seas The most active season ever recorded was 2005, with a total of 27 named storms, of which The record warmth of the decade 2001–2010 15 reached hurricane intensity and seven were was accompanied by the melting of ice classified as major hurricanes (Category 3 or caps, sea ice and glaciers and the thawing higher). Katrina, a Category-5 hurricane, was of permafrost. In addition to being a sign the most devastating hurricane of the decade, of a warming climate, melting ice and snow making landfall in the southern USA in August. also affected water supplies, transport

11 Typhoon Rananim (August 2004) Hurricane Bertha Cyclone Gonu Maximum winds - 165 km/h. Hurricane Katrina (July 2008) (June 2007) Strongest typhoon to affect Typhoon Kompasu (August 2005) Maximum winds - 205 km/h. Zhejiang Province in China (August/September 2010) Maximum winds - 270 km/h. since 1956. Tropical storm Maximum winds - 280 Longest-lived Atlantic July The worst tropical cyclone to Maximum winds - 195 km/h. Strongest typhoon km/h Deadliest hurricane tropical cyclone on record. hit Oman since 1945. to strike Seoul Republic of Korea in 15 years. Allison to strike the USA since (June 2001) 1928. Hurricane Juan Maximum winds - 95 km/h. Deadliest and costliest (September 2003) tropical storm on record in Maximum winds - 170 km/h. Hurricane/typhoon Loke Typhoon Lekima (August/September 2006) the USA. Worst hurricane to hit Halifax, (September/October 2007 Nova Scotia, in modern history. ) Maximum winds - 260 km/h. The strongest Maximum winds - 130 km/h. Produced heavy hurricane ever recorded in the Central rains across Viet Nam, resulting in its worst Pacific Ocean. Tropical storm Fay flooding in 45 years. Hurricane Rick (August 2008) Typhoon Tokage (October 2009) Maximum winds - 110 km/h. First Maximum winds - 270 km/h storm in recorded history to strike (October 2004) The second most intense Florida (or any state) four times. Maximum winds - 230 km/h hurricaneon record for the Deadliest typhoon to strike basin, behind Linda of 1997. Japan since 1979. Hurricane Kenna (October 2002) Maximum winds - 270 km/h. The strongest hurricane to strike Typhoon Durian Mexico from the Pacific since (November 2006) Typhoon Megi hurricane Madeline in 1976 and Hurricane Lili Cyclone Laila (October 2010) third strongest on record. Maximum sustained wind - 230 km/h. (September/October (May 2010) Maximum winds - 295 km/h. The Hurricane Wilma Near 1 200 deaths in the Philippines. 2002) Maximum winds - 120 km/h strongest tropical cyclone in the Hurricane Sergio (October 2005) First may storm to affect world since 2005 and the strongest Maximum winds - 295 km/h. Maximum winds - 230 km/h. Cyclone Nargis in the North-West Pacific since 1983. (November 2006) First hurricane to make south-eastern India in two The most intense Atlantic decades. (April/May 2008) Maximum winds - 175 km/h. hurricane ever recorded. landfall in the USA since hurricane Irene in 1999. Maximum winds - 215 km/h. The most The longest-lived November devastating cyclone to hit Asia since 1991 Cyclone Ului tropical cyclone on record for and the worst natural disaster on record (March 2010) the basin. for Myanmar. Hurricane Michelle Hurricane Ivan Maximum winds - 260 km/h. One (September 2004) of the fastest intensifying tropical (October/November 2001) Maximum winds - 270 km/h. cyclones on record. Maximum winds - 220 km/h. The most powerful storm to Cyclone Dina Tropical storm Alma Strongest hurricane to hit affect the Caribbean in 10 years. (January 2002) (May 2008) Cuba since hurricane Fox in October 1952. Maximum winds - 240 km/h Responsible more details on Australia Maximum winds - 100 km/h. The first Hurricane Catarina for setting a new 24-h precipitation Cyclone Larry eastern North Pacific basin tropical record in Mauritius (745 mm). (March 2006) storm or hurricane to make landfall (March 2004) along the Pacific Coast of Central Maximum winds - 155 km/h. The first Maximum winds - 215 km/h. The America since records began. documented South Atlantic Ocean most intense cyclone to strike the hurricane since geostationary satellite Cyclone Gamède Queensland coast since 1918. records began in 1966. (February/March 2007) Maximum winds - 195 km/h. A new worldwide Cyclone Ingrid Cyclones maximum rainfall record was set in La Réunion with 3929 mm measured in 3 days. (March 2005) wind legend Maximum winds - 250 km/h. The first cyclone recorded to reach category 5 63−118 km/h intensity off the coast of three different 119−153 km/h Australian states: Queensland, Northern Territory, and Western Australia. 154−177 km/h 178−209 km/h 210−249 km/h > 249 km/h

routes, infrastructure, marine ecosystems million km2 – 39 per cent below the long-term and much more. average – occurred in 2007 (Figure 9). This record was broken in 2012. The estimated The state of Arctic sea-ice cover in the volume of Arctic sea ice has also been declining 20th century is relatively well documented. Until markedly since 2005, with a new record set the 1960s, sea ice covered 14–16 million km2 in 2010. Meanwhile, Antarctic sea ice has of the Arctic in late winter and 7–9 million expanded slightly overall, for reasons that km2 at the end of the northern summer. Since continue to be investigated. then it has declined rapidly. The five years with the lowest ever recorded sea-ice extent The world’s two major ice sheets (long-lived in September were 2005, 2007, 2008, 2009 ice accumulated over landmass) are in the and 2010. The record minimum extent of 4.28 Antarctic and Greenland. The loss of net

12 Typhoon Rananim (August 2004) Hurricane Bertha Cyclone Gonu Maximum winds - 165 km/h. Hurricane Katrina (July 2008) (June 2007) Strongest typhoon to affect Typhoon Kompasu (August 2005) Maximum winds - 205 km/h. Zhejiang Province in China (August/September 2010) Maximum winds - 270 km/h. since 1956. Tropical storm Maximum winds - 280 Longest-lived Atlantic July The worst tropical cyclone to Maximum winds - 195 km/h. Strongest typhoon km/h Deadliest hurricane tropical cyclone on record. hit Oman since 1945. to strike Seoul Republic of Korea in 15 years. Allison to strike the USA since (June 2001) 1928. Hurricane Juan Maximum winds - 95 km/h. Deadliest and costliest (September 2003) tropical storm on record in Maximum winds - 170 km/h. Hurricane/typhoon Loke Typhoon Lekima (August/September 2006) the USA. Worst hurricane to hit Halifax, (September/October 2007 Nova Scotia, in modern history. ) Maximum winds - 260 km/h. The strongest Maximum winds - 130 km/h. Produced heavy hurricane ever recorded in the Central rains across Viet Nam, resulting in its worst Pacific Ocean. Tropical storm Fay flooding in 45 years. Hurricane Rick (August 2008) Typhoon Tokage (October 2009) Maximum winds - 110 km/h. First Maximum winds - 270 km/h storm in recorded history to strike (October 2004) The second most intense Florida (or any state) four times. Maximum winds - 230 km/h hurricaneon record for the Deadliest typhoon to strike basin, behind Linda of 1997. Japan since 1979. Hurricane Kenna (October 2002) Maximum winds - 270 km/h. The strongest hurricane to strike Typhoon Durian Mexico from the Pacific since (November 2006) Typhoon Megi hurricane Madeline in 1976 and Hurricane Lili Cyclone Laila (October 2010) third strongest on record. Maximum sustained wind - 230 km/h. (September/October (May 2010) Maximum winds - 295 km/h. The Hurricane Wilma Near 1 200 deaths in the Philippines. 2002) Maximum winds - 120 km/h strongest tropical cyclone in the Hurricane Sergio (October 2005) First may storm to affect world since 2005 and the strongest Maximum winds - 295 km/h. Maximum winds - 230 km/h. Cyclone Nargis in the North-West Pacific since 1983. (November 2006) First hurricane to make south-eastern India in two The most intense Atlantic decades. (April/May 2008) Maximum winds - 175 km/h. hurricane ever recorded. landfall in the USA since hurricane Irene in 1999. Maximum winds - 215 km/h. The most The longest-lived November devastating cyclone to hit Asia since 1991 Cyclone Ului tropical cyclone on record for and the worst natural disaster on record (March 2010) the basin. for Myanmar. Hurricane Michelle Hurricane Ivan Maximum winds - 260 km/h. One (September 2004) of the fastest intensifying tropical (October/November 2001) Maximum winds - 270 km/h. cyclones on record. Maximum winds - 220 km/h. The most powerful storm to Cyclone Dina Tropical storm Alma Strongest hurricane to hit affect the Caribbean in 10 years. (January 2002) (May 2008) Cuba since hurricane Fox in October 1952. Maximum winds - 240 km/h Responsible more details on Australia Maximum winds - 100 km/h. The first Hurricane Catarina for setting a new 24-h precipitation Cyclone Larry eastern North Pacific basin tropical record in Mauritius (745 mm). (March 2006) storm or hurricane to make landfall (March 2004) along the Pacific Coast of Central Maximum winds - 155 km/h. The first Maximum winds - 215 km/h. The America since records began. documented South Atlantic Ocean most intense cyclone to strike the hurricane since geostationary satellite Cyclone Gamède Queensland coast since 1918. records began in 1966. (February/March 2007) Maximum winds - 195 km/h. A new worldwide Cyclone Ingrid Cyclones maximum rainfall record was set in La Réunion with 3929 mm measured in 3 days. (March 2005) wind legend Maximum winds - 250 km/h. The first cyclone recorded to reach category 5 63−118 km/h intensity off the coast of three different 119−153 km/h Australian states: Queensland, Northern Territory, and Western Australia. 154−177 km/h 178−209 km/h 210−249 km/h > 249 km/h

mass from both of these sheets has been have been rising, with the 2001–2010 decade Figure 8. Most significant accelerating, with the largest losses of the marked by an increase in the thickness of the tropical cyclones decade seen in 2007 and 2008. If this trend seasonal thaw layer in many northern areas. recorded during 2001–2010 (source: continues, ice sheets will contribute more NOAA-NCDC) to sea-level rise in the 21st century than any As a result of this widespread melting (and the other factor. thermal expansion of sea water), global mean sea levels continued to rise over the decade The world’s glaciers lost more mass in 2001–2010. The observed rate of increase 2001–2010 than in any decade since records was some 3 mm per year, about double the began. Snow cover declined significantly in the observed 20th century trend of 1.6 mm/yr. northern hemisphere (Figures 10 and 11). The Global sea levels averaged over the decade temperatures of permafrost (frozen land) areas were about 20 cm higher than those of 1880.

13 Figure 9. Sea-ice extent for September 2007; the 12 magenta line indicates the long-term median from the 1979–2000 base 10 period (left) and Arctic sea-ice extent at the end of the summer melt 8 season from 2007 to 2010 (right) (source: National Snow and Ice Data Center, 6 USA) 2010 2009 2008 4 2007 Extent (millions of square kilometres) 1979-2000 Average ±2 Standard deviations 2 July August September October November

15 000

10 000

5 000 Figure 10. Mean cumulative specific glacier mass balance 0 since 1945/1946 (source: World Glacier Monitoring Service) –5 000 mean of 10 mountain ranges (mm water equivalent) mean of 37 glaciers mean of all glaciers –10 000 Mean cumulative specific mass balance –15 000

1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Figure 11. Northern hemisphere snow- 2 cover anomaly for June (1970–2010) (data source: 0 Rutgers University Global Snow Laboratory, USA). –2 Note: No similar data exist for the southern hemisphere –4 Snow-cover extent anomaly (millions square kilometres) as the land area subject to seasonal snow cover –6 (outside the Antarctic) is very small. 1970 1974 1978 1982 1986 1990 1994 1998 2002 2006 2010

14 7. Conclusion Assessing trends in extreme weather and climate events requires an even longer Understanding the Earth’s climate and trends timeframe because, by definition, these in temperature, precipitation and extreme events do not occur frequently. WMO’s events is of vital importance to human well- Commission for Climatology is currently being and sustainable development. As the addressing new approaches for the improved report The Global Climate 2001–2010 confirms, characterization, assessment and monitoring climate scientists can now link some natural of these events. In addition, promising new oscillations to seasonal climate trends. They research into the attribution of individual also understand the mechanisms by which extreme events based on observational and humanity’s greenhouse-gas emissions are model data is starting to emerge. raising global average temperatures. Long-term cryosphere monitoring has While climate scientists believe that it is not emerged as an urgent priority, both for yet possible to attribute individual extremes climate research and for understanding the to climate change, they increasingly conclude practical implications of the widespread that many recent events would have occurred melting. There are still uncertainties with in a different way – or would not have occurred respect to the future evolution of ice- at all – in the absence of climate change. For sheet melting. Understanding cryosphere example, the likelihood of the 2003 European variability will also help to improve sea- heatwave occurring was probably substantially level rise projections, which, in turn, will increased by rising global temperatures. contribute to more effective coastal planning and management. No clear trend has been found in tropical cyclones and extra-tropical storms at the As observation, modelling and scientific global level. More complete datasets will be understanding of the climate system advance, needed in order to perform robust analyses scientists will be able to provide increasingly of trends in the frequency and intensity of useful information for decision-making. This these hazards. will greatly benefit international cooperation through the United Nations Framework Distinguishing between natural climate Convention on Climate Change and the variability and human-induced climate Global Framework for Climate Services. change will also require datasets that are WMO remains committed to supporting these more complete and long-term. A decade efforts through its Members, its programmes is the minimum possible timeframe for and the regular reports made possible by the detecting temperature changes. WMO Climate System Monitoring network.

15 For more information, please contact:

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