4 - Climate change

• Extreme weather events


  Weather events that can cause significant damage and disruption to communities
• Extreme weather hazards in the UK

  • Storms
  • Flooding
  • Drought
  • Extreme cold weather
• Types of flooding associated with extreme weather in the UK

  • Coastal flooding
  • River flash flooding
  • Slow-onset river flooding
  • Surface water flooding
• Storm events can cause great storm damage, especially to the west coast of the UK
• A tornado caused 19 injuries and £40 million in damage in Birmingham in 2005
• Drought


  An extended period of low or absent rainfall relative to the expected average for a region
• The longest drought on record in the UK occurred over an 18-month period in 1975 and 1976
• The 2003 heatwave affected large parts of Europe and was linked with up to 70,000 deaths
• The 2019 heatwave brought the highest temperature ever recorded in the UK: 38.7°C in Faversham, Kent
• Weather risks associated with extreme cold

  • Frost
  • Freezing conditions
  • Blizzard conditions
• Over 17,000 trains were cancelled in January 2014 because of freezing conditions
• Scientists say the floods that hit northern England during Storm Desmond in December 2015 were the most extreme in 600 years
• At Honister Pass in Borrowdale, 341 millimetres of rain fell in just 24 hours, setting a new record for the UK
• More than 4,000 homes were affected by river flooding and surface water flooding in Cumbria
• Over 100 bridges were damaged, including 600-year-old Eamont Bridge
• Hundreds of businesses in Allerdale and Carlisle remained closed for over a year
• The recovery cost £500 million and the insurance bill reached £1.3 billion
• More than 700 families were unable to return to their homes for around two years
• The UK government has provided over £150 million to support recovery in Cumbria since 2016
• Flood defences have been strengthened throughout the Cumbria region
• £24 million has been spent on flood defences in Kendal
• Rainfall record and changes in storm frequency
• Temperature record and changes in drought frequency
• Future extreme weather predictions
• A range of data suggests that the Earth's climate is currently warming and changing. The rate of change is unprecedented in historical terms, which is why the majority scientific viewpoint is that humans are to blame
• The Intergovernmental Panel on Climate Change (IPCC) of the United Nations has warned that temperatures could increase by several degrees during this century
• A warmer world will be one where more evaporation takes place over the oceans – and what goes up, must ultimately come down. Climate change scientists therefore believe that rainfall patterns are likely to change in the UK as the world's oceans warm, and are in fact doing so already
• Increased warming of the Atlantic ocean

  Rain-bearing depressions gained more energy and moisture
• Recent storms and floods may already have 'human fingerprints' on them
• UK temperatures have increased by about 1 °C since 1980
• High temperatures alone do not cause drought; there must also be rainfall deficiency
• IPCC scientists admit that future rainfall trends for a warming world are hard to predict, as there are so many variables to consider
• Some scenarios suggest a global average temperature rise of up to 4°C in the twenty-first century
• Several agencies, including the Environment Agency and the Met Office, believe that if this happens, the UK could be faced with warmer and wetter winters
• There may be more rain-bearing depressions affecting all parts of the UK, not just northern regions. The risk of extreme flooding and high wind speeds will probably increase
• There are also long-term cyclical changes in the temperature of the Atlantic ocean and the position of the jet stream
• Taking the highest scenario shown in Figure 3.30, a global average temperature rise of 4°C would cause widespread melting of land and sea ice in the Arctic. Colder water would pour into the north Atlantic, with unknown effects for the movement of the air masses and ocean currents that regulate the UK's climate. In a warmer world, the UK could be left facing more extremes of cold weather!
• Precipitation will become even more seasonal
• The frequency and magnitude of winter river flooding has increased since the 1980s
• We are not sure if evaporation has increased or not. But we know temperature has risen by 1 °C