2001 – 2010 A decade Of Climate extreMes WMO-No. 1103 THE GLOBAL CLIMATE 2001–2010 A DECADE OF CLIMATE EXTREMES Contents Page Foreword vi Introduction viii Chapter 1 Temperature assessment 2 1.1 Global temperature Feature article Assessment of global temperature based on reanalysis data 1.2 Regional temperature 1.3 Temperature assessment at country level 1.3.1 General result 1.3.2 Analysis by continent Chapter 2 Precipitation assessment 10 2.1 Global precipitation 2.2 Regional precipitation 2.2.1 Decadal assessment summary 2.2.2 Annual assessment summary Chapter 3 Large-scale climate variability modes and related oscillation indices 14 Overview 3.1 El Niño/Southern Oscillation 3.2 Arctic Oscillation/North Atlantic Oscillation 3.3 Indian Ocean Dipole 3.4 Southern Annular Mode Chapter 4 Extreme events 19 4.1 Impact assessment 4.1.1 Data and methodology 4.1.2 Comparison of 2001–2010 with 1991–2000 4.1.3 Regional analysis 4.1.4 Other aspects of impacts 4.2 Exposure, vulnerability and attribution of climate extremes 4.2.1 Increased exposure and vulnerability to hydrometeorological events 4.2.2 Attribution of climate extremes 4.3 Summary statistics from country data 4.3.1 Most reported extreme events 4.3.2 Country absolute records 4.4 Worldwide summary of extreme climate conditions 4.4.1 Heatwaves and abnormally high temperature conditions Case study A1 Extreme heatwaves in Europe in 2003 Case study A2 Extreme heatwave in the Russian Federation in 2010 Case study A3 Exceptional heatwaves in Australia in 2009 4.4.2 Cold waves, abnormally low temperature conditions and snowstorms Case Study B Extreme winter conditions over the northern hemisphere (2009/2010) 4.4.3 Flooding and heavy precipitation Case study C The severe Pakistan flooding of 2010 iv Page 4.4.4 Droughts Case study D1 Long-term drought in Australia Case study D2 Long-term drought in the Amazon Basin Case study D3 Long-term drought in East Africa 4.5 Severe storms 4.5.1 Tropical cyclones Case study E1 Hurricane Katrina Case study E2 Cyclone Nargis 4.5.2 Extra-tropical cyclones and storms Case study F Extra-tropical windstorms in Europe Case study G Sand- and duststorms in the Arabian Peninsula 4.5.3 Tornadoes Chapter 5 Climate and composition of the atmosphere 76 5.1 Greenhouse gases and climate 5.2 Stratospheric ozone depletion 5.3 Climate and air quality Chapter 6 Cryosphere and sea level 84 6.1 Cryosphere 6.1.1 Sea ice 6.1.2 Ice sheets 6.1.3 Glaciers 6.1.4 Snow cover 6.1.5 Permafrost and frozen ground Feature article Effects of unseasonably mild conditions on the ice-road network and traditional lifestyles in northern Canada 6.2 Sea level Conclusion 94 Acknowledgements 97 References and bibliography 98 Acronyms 102 Glossary 104 Annex 1. Source and methodology for global surface-temperature assessment 106 Annex 2. Country survey – general information 108 Annex 3. Country data submission to the WMO survey 109 v Foreword The goal of the WMO Climate System Monitoring is to deliver timely, authoritative information on the status of the atmosphere, ocean, cryosphere and biosphere at sub- monthly, monthly, annual and decadal to multi-decadal timescales. WMO Members have been collaborating on Climate System Monitoring over several decades to achieve improved monitoring and understanding of climate variability and climate change and related extreme weather and climate events. Nowadays, with modern communication technology, WMO Members issue timely and regular reports on their websites, thus marking a fundamental shift in the way monitoring products are disseminated. These products have become crucial inputs to the various decision- making processes of user communities, in addition to their traditional scientific purpose. Improved Climate System Monitoring today allows a quick analysis of monthly and seasonal climate drivers, such as El Niño/Southern Oscillation, the Arctic Oscillation and the North Atlantic Oscillation, among others. This information is increasingly being used to help foresee potential positive or negative impacts on sector activities such as agriculture, water resources, health, energy, tourism and fisheries. In addition to the WMO Annual Statements on the Status of the Global Climate, which have been produced regularly since 1993, WMO produced, in 2003, a six-year climate review covering the period 1996–2001 with more comprehensive data and information. The main content of the review was based on the annual State of the Climate reports which are published by the National Oceanic and Atmospheric Administration-National Climatic Data Center of the United States of America in the Bulletin of the American Meteorological Society. In 2005, the WMO Commission for Climatology recommended discontinuing the multi-year climate review and agreed instead to publish a five-year climate summary to complement the WMO annual statements. This publication covers the first decade of the 21st century and aims at providing a decadal perspective of climate variability and change and its observed impacts on different sectors. The decade 2001–2010 was characterized by a record global temperature increase since sufficiently comprehensive global surface temperature measurements began in 1850. For global land-surface air temperatures, as well as for ocean-surface temperatures, this decade was the warmest on record. Despite interannual variations in the global temperature, which are driven by large-scale variability in the ocean and the atmosphere, the underlying long-term trend is clearly an upward one. Except for the year 2008, the nine remaining years of the decade, together with 1998, constitute the top 10 warmest years on record since 1850. The decade was also the warmest on land, over the oceans and in the northern and southern hemispheres when taken separately in the assessment. Flooding was reported by the great majority of countries as the most significant extreme event they faced during the decade, followed by droughts, flash floods, heavy rainfall, heatwaves and severe storms. Twelve studies are provided in this report to illustrate a few of the most significant extreme weather and climate events which caused high human and economic losses. vi Carbon-dioxide concentration had reached an average global value of 389 parts per million by the end of the decade, the highest value recorded for at least the past 10 000 years. The dramatic and continuing sea-ice decline in the Arctic is one of the most prominent features of the changing state of the climate during the decade with the five lowest minimum sea-ice extents at the end of the melting season, all recorded in the second half of the decade, with the record being set in 2007. I am confident that this publication will provide added value to the great collective efforts by Members to deliver useful climate services to governments, user communities, research, academia and the public at large. I wish to thank all the Members that responded to the WMO survey with the aim of collecting climate data and information on the decade 2001–2010. I also extend WMO’s thanks to the international centres which continuously maintain climate datasets to the highest possible scientific standards, as well as their useful global climate monitoring, the results of which are continuously updated on their websites. Last but not least, I would like to thank the many experts from various nations and organizations and the UN partners that participated in the preparation of this publication. (Michel Jarraud) Secretary-General vii Introduction The international collaboration underpinning Climate System Monitoring (CSM) involves monitoring the present state of the global atmospheric, oceanic and terrestrial climate system. The monitoring covers many aspects of the atmospheric and ocean conditions, cryosphere, trace gases, etc. Data sources include in situ and space-based observations collected through various WMO and co-sponsored programmes and numerical objective analyses. These observations and analyses provide useful information for the interpretation of the present climate, including extreme events and long-term trends. WMO CSM uses essential climate variables (ECVs) as defined by the Global Climate Observing System (GCOS). Some 50 ECVs have been identified as feasible for global observation. The present report incorporates assessments of the status of the global climate and the observed extremes detected using ECV data and products, including air temperature, precipitation, wind speed, greenhouse-gas concentration (atmospheric ECVs); snow cover, fire disturbance and river discharge (terrestrial ECVs); as well as sea ice, ice sheet and sea level (oceanographic ECVs). Climate assessment on the decadal timescale offers the necessary data and information to enable robust understanding of the varying and changing climate and places climate monitoring in an extended historical time frame, such as is not possible with the annual climate monitoring. The Global Climate 2001–2010 is a new WMO publication summarizing the state of the climate for the decade 2001–2010 and its assessment in the historical context. It complements the annual WMO statements on the status of the global climate and the more comprehensive annual report State of the Climate, which is published regularly in the Bulletin of the American Meteorological Society (BAMS) by the National Oceanic and Atmospheric Administration-National Climate Date Center (NOAA-NCDC) of the United Sates of America (USA). The data and information used in this publication are based on international datasets that are maintained by advanced climate data, monitoring and research centres which collaborate with WMO and the data and climate information collected directly from Member countries through a special WMO survey. The methodologies used for analysing the data and describing the results in various chapters were reviewed during a special two-day expert review meeting which was hosted by the University of Rovira i Virgili, Tortosa, Spain, 22-23 November 2011. Subsequent reviews were undertaken with other individual experts.