Climate change — the facts
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What does it mean for the world?
Climate change will mean warmer temperatures which will change rainfall patterns, cause snow and ice to melt and affect the intensity of extreme weather such as storms and heatwaves. We have already begun to experience some of these impacts and many other knock-on effects:
- Water and food — around 1.5 billion people currently live in water-stressed regions. Climate change and population growth could increase this to seven billion by the 2050s, intensifying competition for this life-giving resource. Some areas could become more fertile; others more barren. This may lead to regional food shortages, mass migration and poverty. Malnutrition is expected to increase in developing countries. Source: IPCC 2007.
- Health — our well-being will be threatened by more frequent and intense heatwaves, floods, storms, wildfires and droughts. However, deaths from cold-related diseases will reduce. Patterns of disease will also change, with wide areas of the world at risk from major diseases, such as Dengue.
- Environment — coastal areas will experience more flooding from rising sea-levels, especially large river deltas which tend to be highly populated, e.g. the Nile Delta. Meanwhile, some areas will attract more tourism as their climates alter.
- Ecosystems — Amazonia is already damaged by deforestation. Climate change may magnify this impact by increasing the risk from fire. Other precious areas of high biodiversity, such as in South Africa, may see major losses of species as habitat conditions change. Around the world, some animals and plants may benefit and flourish in a changing climate, while others are likely to suffer.
What about the UK?
Even across relatively small areas like the UK, climate change is expected to cause marked regional differences in temperature and rainfall by the end of the 21st century.
How our climate has changed
- Central England temperatures have increased by 1 °C since 1970s.
- Total summer rainfall has decreased in most parts of the UK.
- Sea surface temperature around the UK has risen by about 0.7 °C, over the past three decades.
- The UK has experienced nine of the 10 warmest years on record since 1990.
- Sea-levels around the UK have risen 10 cm since 1900.
How our climate may change
- Under a medium emissions scenario, the annual average temperature rise by the end of the century is very likely to be more than 2 °C and less than 5 °C. The central estimate is 3.5 °C.
- Temperatures are expected to rise across the UK with more warming in summer than in winter. The summer average temperature rise in the south-east is very likely to be above 2 °C and below 6.4 °C. The central estimate is 4 °C.
- The urban heat island effect already warms central London by more than 10 °C on some nights. Increased urbanisation and release of waste heat would increase this still further — on top of the effects of global warming.
- As summers become warmer and drier droughts are more likely, particularly in the south-east. There may also be more intense downpours of summer rainfall, which could lead to flash flooding.
- The extreme heatwave of 2003, where average summer temperatures were 2 °C higher than normal, led to more than 2,000 additional deaths in the UK. Such hot summers could happen every other year by the 2040s.
- Heavier winter precipitation is expected to become more frequent, potentially causing more flooding.
- Sea-level across the UK is projected to rise between 11 and 76 cm by the end of the century. In the worst case, rises of up to 1.9 m are possible but highly unlikely.
How we’ll need to adapt
Many aspects of our lives and lifestyles will be affected by climate change. We can adapt to reduce the impact of many, but not all, of these changes.
| Energy | Water | Agriculture | Built environment | Transport | |
|---|---|---|---|---|---|
| Extreme weather | The UK’s energy infrastructure is at risk from extreme weather, such as flooding and heatwaves. | Wetter winters and sea-level rise will increase flood risk in the UK. | Extreme weather, such as storms or heatwaves, can cause major damage to crop yields. | Buildings in the UK will have to withstand more extreme weather — increased temperatures and rain. | Increased temperatures and rain will have a big effect on road and rail networks in the UK. |
| High temperatures | Hotter UK summers will increase the demand for air-conditioning; less heating will be needed in winter. Power cables under-perform when it is hot. | Higher temperatures could cause water demand to rise. | Higher year-round temperatures could allow new crops to flourish in the UK. Diseases and pests could survive milder UK winters. | People will be more vulnerable to heat stress caused by increased temperatures and humidity. | Road surfacing will melt unless replaced with different materials. |
| Drought | Many power stations use water from rivers to cool their turbines — less water will be available, increasing competition with other water users. | Droughts will increase current pressure on water demand, supply and quality — including in the UK. | Longer droughts could reduce UK crop yield or increase demand for irrigation, but will hit eastern parts of the UK the hardest. | Drier soils lead to subsidence — foundations may have to be very deep to reach more secure soil. | Subsidence caused by changes in soil-moisture content may lead to more frequent and expensive repair of infrastructure. |
| Floods | In the UK, many power stations are situated on the coast, so future planning will need to account for predicted sea-level rise. | Sewage flooding could increase due to more heavy rainfall. | More heavy rain will lead to increased risk of flooding. This will wash out nutrients and lead to waterlogging of fields. | The location of building projects, drainage and flood-resilient construction will be increasingly important in the UK. | Coastal roads and railways are threatened with wetter UK winters, intense rainfall, coastal erosion and sea-level rise. |
| Urban heat island | Cities tend to be much warmer than their surroundings. Peaks in electricity demand due to air-conditioning occur during summer heatwaves. | Higher urban temperatures will increase water consumption, including demand associated with cooling buildings and watering gardens and parks. | Higher winter temperatures in cities can support the life cycle of some non-native agricultural pests which can spread into rural areas. | Reflective roof coverings and light-coloured building materials can help combat over-heating in cities. | Summer temperatures, which can already reach uncomfortable levels on public transport systems in UK cities, are set to increase. |
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