Living With The Extremes
First Southeast Asia Workshop Engineering for Climate Extremes Partnership 29 January 2018
Edwin S T Lai (黎守德) Connecting weather / climate events with potential risk
Wet or Dry Fog/Mist/Haze Thunderstorms (tornadoes and hail) Squall Lines Rainstorms Tropical Cyclones Winter Storms Heat Waves Cold Spells Climate Change 1.5°C vs 2°C world
Heat wave Longer
Water resources Drier
Increased Extreme rainfall intensity
Mean sea level Higher rise
Reduction Food insecurity in crop yield in tropics
3 Source: Schleussner et al (2016) The Consequence of Global Warming
Enhance greenhouse effect Rising temperature
Thermal expansion of sea water & melting of snow on Sea level rise land
Regional differences in Change in atmospheric precipitation and more circulation and enhanced frequent extreme weather water cycle and climate events The Consequence of Global Warming
Enhance greenhouse effect Rising temperature
Thermal expansion of sea water & melting of snow on Sea level rise land
Regional differences in Change in atmospheric precipitation and more circulation and enhanced frequent extreme weather water cycle and climate events A brief overview of extreme weather and climate events
Extreme event is : An integral part of the Earth’s climate system An infrequent and/or unseasonal event which is significantly different from "the norm" in terms of frequency, severity, duration and/or timing Can have large regional and local variations in definition May have significant impacts to various sectors of the society Usually caused by a combination of factors – ranging from large scale climate and weather systems to local weather interactions Climate change will likely increase the frequency of occurrence and severity of some extreme weather events (e.g. extreme temperatures, rainstorm, flooding, severe typhoons, drought, etc).
Taking temperature as an example, the probability of occurrence of a temperature usually follows a normal distribution with a very low probability of occurrence (usually less than 5%) for extremely high or low temperature.
Reported disasters in Asia (1970–2010)
Economic losses increase alongside with the increase in disaster number, economic development, population growth and urbanization.
(Source : WMO No. 1123 - Atlas of Mortality and Economic Losses from Weather, Climate and Water Extremes (1970–2012)) Extreme weather and climate events in Hong Kong
• Extremely hot and cold weather • Rainstorms and thunderstorms • Drought • Typhoons & storm surge Past trends and future projections of extreme weather and climate events in Hong Kong Observed climate change in Hong Kong Hong Kong climate projections in the 21st century
4°C world
2°C world
12 Record breaking temperature events in Hong Kong
Record breaking temperature events in Hong Kong 36.8 2017: 36.6℃
2015: 36.3℃ 36.3
1900: 36.1℃ 1990: 36.1℃ ℃)
) 35.8
攝氏度 ( 35.3
年最高氣溫 34.8 1892, 1895,
Annual maximum temperature ( temperature maximum Annual 1896: 34.4℃ 34.3 1890: 34.3℃
1884: 33.9℃ 33.8 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 年份 Year Record-breaking high temperature events in 2017
Record-breaking Events Date / Period New Record (since records began in 1884) Highest Monthly Mean Temperature for January 2017 18.5oC January Highest Monthly Mean Minimum January 2017 17.0oC Temperature for January Highest Daily Mean Temperature for July 30 July 2017 31.8oC*
Maximum Temperature 22 August 2017 36.6oC
Highest Monthly Mean Temperature for September 2017 29.0oC* September Highest Monthly Mean Minimum September 2017 27.2oC Temperature for September Highest Mean Temperature for Winter December 2016 to 18.4oC* February 2017 Highest Annual Number of Hot Nights** 2017 41 days
*tied highest record **'Hot Night' refers to the condition with the daily minimum temperature equal to or higher than 28.0 degrees Projected increase in very hot days and hot nights in Hong Kong in the 21st Century
RCP4.5 RCP8.5 Medium-low concentration scenario High concentration scenario
Hot nights - days with a minimum temperature of 28°C or above Very hot days - days with a maximum temperature of 33°C or above Icing due to freezing rain at Kadoorie Farm, Tai Po, on 24 January 2016
Icy and slippery roads at Tai Mo Shan on 24 January 2016, emergency services coming to the aid of trapped Ice pellets observed at Tai Mo Shan Radar Station on hikers at Tai Mo Shan 24 January 2016 More frequent record breaking rainfall Changes in the chance of rainfall extremes in the last century Examples of extreme weather – Rainstorm on 16-18 June 1972
The persistence of the heavy rain during 16 to 18 June 1972 caused serious landslides at Pos Shan Road of Hong Kong Island and Sau Mau Ping resettlement areas at Tsui Ping Road, Kwun Tong, resulting in 150 deaths. Po Shan Road Sau Mau Ping
(photo courtesy : GEO, CEDD)
(Photo source : https://mmis.hkpl.gov.hk/kt_03) Examples of extreme weather – Rainstorm on 7 June 2008 The heavy downpour on the morning of 7 June brought a record breaking hourly rainfall of 145.5 mm at HKOHq.
24 hour rainfall distribution ending at 11:00am Flooding of North Lantau Highway on 7 June 2008
(Photo courtesy of GEO) Landslides in Tai O, Lantau Examples of extreme weather – Localized heavy rain on 7 October 2015 in Sai Kung
(Photo courtesy : Sky Post and Ming Pao) Future changes in extremely wet and extremely dry years in Hong Kong under different greenhouse gas concentration scenarios
RCP4.5 RCP8.5 Medium-low concentration scenario High concentration scenario Examples of extreme weather – The extreme drought in 1962-1964
The total rainfall in Hong Kong in 1962 was only 1741 mm, well below the normal of about 2214 mm (1961-1990). The suitable became even worse in 1963 with a total rainfall of 901 mm, the lowest on record.
Water rationing with water supply once every 4 days Long queue at a public standpipe, 1963
(Photo source : GRS and WSD) A warming world that fuels the storms
Climate Change Possible effects Potential impacts
Warmer ocean Provide more energy for Increase the risk of wind storm development and damages breed intense typhoons
Warmer atmosphere Enhance the moisture- Increase the risk of holding capacity of the flooding and landslips lower atmosphere and typhoon-induced rainfall
Sea level rise Make storm surge more Increase the risk of frequent and bring more coastal flooding and extreme sea levels inundation damages Tropical Cyclone Metrics I All TC frequency II Cat 4-5 frequency III Lifetime Max Intensity IV Precipitation rate
IPCC-AR5 (2013) Examples of extreme weather – Super Typhoon Hato in 2017
• Storm force winds in the Harbour • Hurricane force winds over southern Hong Kong, e.g. Cheung Chau • Extreme sea level due to storm surge of Hato coincided with astronomical high tide
Over 5,300 fallen trees Damages of curtain walls Flooding by sea water Siu Sai Wan (Photo courtesy: Charmaine Mok)
(Photo courtesy : Ray Kong) (Photo courtesy : Kevin Campbell)
Vessels in distress Coastal damage
Cheung Chau (Photo courtesy : GFS) (Photo courtesy : Remington Yu)
(Photo courtesy : Steve Lee) Video showing sea water flowing into the underground car park Sea water flowing into Heng Fa Chuen
(Video courtesy : Godfrey Ho) (Video courtesy of Kitty Lam) Hato Major Impacts – Storm Surge Recorded maximum sea level (mCD) and flood reports on 23 Aug 2017
尖鼻咀 Tsim Bei Tsui 高流灣 4.56 Ko Lau Wan 大埔滘 3.58 Tai Po Kau Macao 4.09 馬灣 Ma Wan 5.26 mCD 3.43 葵涌 (could be Kwai Chung 3.52 ) 3.29# 5.6 mCD 3.87 赤鱲角 鰂魚涌 大澳 Chek Lap Kok Quarry Bay 大廟灣 Tai O Tai Miu Wan 3.57 3.14# 由各部門負責管理的潮汐站 Tide gauge managed by 香港天文台 Hong Kong Observatory 海事處 Marine Department # 橫瀾島 渠務署 Drainage Services Department 3.91 3.56 Waglan Island 機場管理局 Airport Authority 石壁 長洲 # Shek Pik Cheung Chau 2.97 # Maximum water level derived from incomplete data
(based on flood reports from government departments, news, and social media) Weather and climate services in Hong Kong - spatial and temporal coverage
Weather services time scale Climate services time scale
Sub-hour to Days Weeks Month Season Annual Decades Century Hours
Site
Nowcasting District & Site specific Weather forecasts forecasts Territory (1-9 days) Extended outlook*, Seasonal forecast & -wide Climate projections Annual outlook
* Extended outlook up to 14 days will be launched later in 2017
Various weather warnings and advisories Severe weather and corresponding warning services in Hong Kong
High winds Heavy rain Extreme temperatures
TC warning signals Color rainstorm Cold and Very Hot No. 1, 3, 8, 9 & 10 warning signals warning
Frost warnings
Landslide warning
Dry conditions Special Announcement on Flooding in the Northern NT Color fire danger warnings Strong Monsoon Signal
Thunderstorm warning Services, partnerships and stakeholder engagement in the development of RISK-BASED FORECASTS and IMPACT-BASED WARNINGS The Global Framework for Climate Services (GFCS)
Five priority areas : Liaison Meetings with Government Departments before Typhoon & Rain Season
• Geotechincal Engineering Office • Drainage Services Department • Transport Department • Home Affairs Department • Education Bureau • Hong Kong Examination & Assessment Authority • Security Bureau
• Review existing procedures • Propose new initiatives or requirements • Update contact list • Promote better working relationship • Arranging Communication Exercise / Drill • Outlook for the year: e.g. No. of TCs, annual rainfall, etc DRR and Contingency Planning Drill and exercise on 24 July 2017
(photo courtesy of the Information Services Department)
Live action during Hato on
(photo courtesy of Civil Aid Service). 23 August 2017 Summary
Learn from the past, different extreme weather events can happen in Hong Kong and result in significant impacts to our society, particularly for vulnerable groups and in vulnerable areas .
Against the background of climate change and local urbanization, Hong Kong will expect even warmer weather, more variable rainfall, and a sea level that keeps rising in the coming centuries. This may affect the frequency and severity of various extreme weather and increase the risk of related impacts.
To prepare for the future, what is adequate today may not be good enough in the foreseeable future. We should not be complacent but raise public awareness on natural disaster preparedness and make a concerted effort to take appropriate measures to ensure Hong Kong’s safe and sustainable development, not only now but for the generations to come. The Frog in the Pot
The change is too trivial to be of serious threat
The change is gradual enough to react
The change is not going to happen here
The change is far too distant in the future to be of my concern The Frog in the Pot
The change is too trivial to be of serious threat
The change is gradual enough to react
The change is not going to happen here
The change is far too distant in the future to be of my concern
未雨綢繆 Preparing for a rainy day - recognizing near and present danger is the key to good planning for a clear and pleasant future! THANK YOU